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The Auto Prof joins MACS Training Event

September 23, 2022

The Auto Prof is an automotive technical training organization. Company principal, Mike Bailey is a licensed automotive technician and instructor since 1991.
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Mastercool returns to MACS Training Event

September 22, 2022

“Mastercool is celebrating our 40th year of supplying professional quality air conditioning service tools and equipment. As one of the fastest growing companies in this market, our primary goal is to drive new product innovation and technologies to make the everyday work of the automotive technician easier.”
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Trans/Air MFG Returns as a MACS exhibitor

September 21, 2022

Trans/Air Manufacturing, Corp. is setting new standards of comfort, reliability, and value for climate control in conventional, electric and hybrid buses and coaches.
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An RRR Machine Test

September 20, 2022

The purpose of the test was to compare the recovery capability of two different R-134a R/R/R machines. One was an older machine which met the old SAE standard J2210. The other was a newer machine which met the SAE standard J2788 which was adopted in 2007and is still the latest standard for R-134a machines.
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Ritchie Engineering Company, Inc. returns to exhibit at MACS Training Event and Trade Show

September 20, 2022

Ritchie Engineering Company, Inc. is a leading worldwide supplier of U.S. designed and manufactured tools and equipment for the HVAC/R and automotive industries.
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MACS welcomes Coyote International, LLC.

September 19, 2022

When you visit the Coyote International exhibit booth you can see their selection of louvers, hose adapters, switch plates, grilles, vents, hose protectors, control knobs, switch plates, water connectors, thermoplastic rubber parts, and nut covers.
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Pacific Best returns to MACS TraDE Show

September 16, 2022

Participating members of MACS since 1999, Pacific Best Inc. (PBI) is a manufacturer’s master distributor of automotive cooling products. PBI offers the greatest selection of radiators, condensers, fan assemblies, intercoolers, external oil coolers and more for all makes and models. The manufacturers we partner with use the most advanced equipment and are operated by an experienced and professional team.
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Robinair returns as an exhibitor and Silver sponsor

September 15, 2022

Robinair is a global leader in service tools and equipment based in Owatonna, Minnesota. Products serve the heating/ventilating/air conditioning/refrigeration (HVAC-R) and mobile markets, which includes the automotive aftermarket along with other industries such as agriculture and construction.
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CPI Fluid Engineering is a new MACS exhibitor

September 14, 2022

CPI, founded in 1971, is a global expert in engineering fluids for challenging applications in heat transfer and compression.  “Our mission is to advance the industries we serve by providing world-class engineered performance fluids, unmatched customer support and innovative collaboration.”
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Don’t overlook a diagnostic clue

September 13, 2022

When thinking about the topic of A/C diagnostic tools, a recovery, recycle, recharge machine (R/R/R machine) is not one of the first tools that comes to mind.  It may not come to mind at all in the world of inexperienced technicians. 
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UAC returns as a MACS Exhibitor

September 13, 2022

UAC is a family owned and operated company since 1988, from Mansfield, TX specializing in Temp Control and Engine Cooling products.
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MACS Welcomes Inficon to 2023 Trade Show

September 12, 2022

NFICON offers a full line of leak detectors for automotive applications. From standard refrigerants like R134a and R1234yf to CO2 and hydrogen forming gas applications, INFICON can help.
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IGas To Exhibit at MACS 2023 Trade Show

September 9, 2022

iGas USA, Inc. offers a full range of refrigerants. Originally joining MACS in 2017, iGas explains, “Our strength, and our mission, is to develop and bring to the market innovative solutions that will have a positive effect on a company's work and business. Each day we strive to design creative, safe and high-quality products that will: assist in lowering your cost of business, make daily work requirements easier, faster, and more economical and improve working conditions and the environment.”
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MACS Welcomes Burgaflex

September 8, 2022

Burgaflex returns as an exhibitor and golf hole sponsor to MACS Training Event and Trade Show . The MACS training event will take place February 2-4, 2023, at the Gaylord Opryland Resort and Convention Center in Nashville, TN.
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T/CCI MFG Awarded Illinois’ First Reimagining Electric Vehicle Tax Incentive Package to Support Major Investments in Transportation Manufacturing and Infrastructure

September 7, 2022

MACS member T/CCI Manufacturing, a global leader for compressor technology, has received Illinois’ first Reimagining Electric Vehicle (“REV Illinois”) Tax Incentive package established by Governor J.B. Pritzker and the Illinois Department of Commerce and Economic Opportunity (DCEO).
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You Knucklehead, you caused this compressor to lock up!

September 7, 2022

Last week's article ended with the following: "As I was completing the job, it hit me what had happened and my first thought was:  You Knucklehead, you caused this compressor to lock up!"  
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MACS Welcomes ATech as an exhibitor

September 7, 2022

ATech Training was founded in 1984 with a desire to develop products that aid instructors in presenting a hands-on approach to teaching and learning the skills of diagnosing and repairing vehicles.
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Airworks will exhibit at MACS 2023 Trade Show

September 6, 2022

MACS is happy to welcome Airworks as a return exhibitor to MACS Training Event and Trade Show . The big event will take place February 2-4, 2023, at the Gaylord Opryland Resort and Convention Center in Nashville, TN. The Trade Show will be on Friday, February 3 from 10:30am-4pm
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MACS Welcomes Globus Electronics

September 2, 2022

MACS warmly welcomes Globus Electronics back to the MACS Trade Show from their native Brazil. Globus Electronics has been an active MACS member since 2009.
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Charging buses and other large systems

September 1, 2022

I have been in the transportation climate control industry for 30 years now and have had the good fortune to have learned from some of the best people in the industry. Although I specialize in the school and transit bus sector, all large systems pose the same certain challenges that require the use of proper equipment and tools to perform the repairs correctly.
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MACS Welcomes FutureTech

August 31, 2022

FutureTech has been an active member and supporter of MACS since 2017 and we once again welcome them to the MACS Trade Show as an exhibitor.
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Unlocking the compressor Lock up, PT. 2

August 30, 2022

I was driving the van home in the afternoon. It was about 45° F outside and the heater was on. It had been an uneventful 15 to 20 minutes’ drive at about 55 to 60 mph. Slowing down to make a 90 degree turn on to a different road, a faint grinding noise was heard. I rolled the window down and drove along at about 5 MPH and could hear the noise more distinctly. The next step was to pull over into a parking lot and leave the engine running and raise the hood.
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Unlocking the compressor lock up

August 23, 2022

I noticed the temperature inside of the van had increased a bit. Placing my hand near a vent, I also noticed that the airflow had decreased and increasing the blower speed did not increase the airflow much.
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Why did the compressor lock up, part 2

August 16, 2022

The relay was sticking in the on position and the compressor would not cycle off when the clutch cycling switch turned the power off to it.
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Why did the compressor lock up?

August 10, 2022

All too often when a compressor lock-up occurs, the compressor itself is blamed for the lock-up. While it is possible for a manufacturing defect to cause a lock-up, there is usually a problem related to the service work or a problem with the system that is the culprit.
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Acura Blower Motor Issue

August 4, 2022

MACS member Rob Bollinger discusses a 2015 Acura TLX blower motor issue and installation
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Do you know about the B1479 trouble code?

August 3, 2022

If you work on Toyota, Lexus and Scion A/C systems, chances are that you have encountered a B1479 diagnostic trouble code on a system that will not operate. 
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An expansion valve myth explored

July 26, 2022

I have encountered many tech calls where a technician had replaced an expansion valve because of a problem with an evaporator freezing up and was frustrated because that did not fix the problem.
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MACS 2023 Training Event and Trade Show

July 21, 2022

Mark your calendar for MACS 2023 Training Event to take place February 2-4, 2023 in Nashville, TN.
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Improving A/C cool down time

July 19, 2022

If there is an issue with an A/C system, then obviously that needs to be fixed and that will aid in cool down time.  However, if a system is working properly and a customer is complaining, then the focus needs to shift toward educating the customer on steps they can take to improve cool down time.
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A/C not cooling fast enough

July 13, 2022

When a vehicle sits outside in direct sunlight, a tremendous amount of heat can build up inside.  Even with relatively  mild summer ambient temperatures  (75° F to 80°F) vehicle interiors can easily reach temperatures of 125° F or more. Consider that this heat is not just in the air inside, but also in the seats, dashboard, floor board, roof, door panels, etc, (essentially the entire inside of the vehicle).
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Diagnosing Faults on Modern Motor Vehicles

July 8, 2022

Motor vehicles have become increasingly more complex over the last two decades to meet the ever-tightening emissions regulations and increased fuel economy requirements, as well as passenger comfort and safety. This added complexity means technicians are flooded with additional data when diagnosing faults on vehicles. Below is a table outlining the difference between a modern vehicle and a vehicle from 20 years ago. This is only a high-level example to illustrate the differences
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It’s still not blowing cold enough

July 6, 2022

This customer came in with this car (he provided the vehicle information) and said it isn't blowing cold enough and wants me to make it blow colder.  He just recently bought it and this is the first “hot spell” we’ve had since he’s had it.
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Electric truck service opportunities

July 1, 2022

For many of these eTrucks, there are going to be one, two, or possibly more, systems using refrigerant on the vehicle. I am not going to discuss any specific systems, because many of them are proprietary, but we can still talk about the generic packages, how to identify them, what can be serviced in a regular shop, and what to avoid at all costs!
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It isn’t blowing cold enough

June 29, 2022

"It isn't blowing cold enough.” Most any auto repair shop that does A/C work will often hear customers say this phrase. It can be the result of any number of things that can be wrong with an A/C system.  Often it is a case of common things such as, a low refrigerant charge, a refrigerant overcharge, contaminated refrigerant,  a blend door issue, a cooling fan problem, or maybe a weak compressor.
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The importance of A/C system oil balancing

June 21, 2022

Sometimes we encounter information where directions instruct us to drain the compressor being removed from a system and measure the amount of oil that drains out. Then the next step is to subtract this number from the number of ounces that are supposed to be in the shipped replacement compressor.
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Refrigerant Oil capacity

June 15, 2022

When an air conditioning system is first assembled, all components (except the compressor) are refrigerant oil free. After the system has been charged with (R-134a) refrigerant and operated, the oil in the compressor is dispersed through the lines and components. The evaporator, condenser, and receiver/ drier will retain a significant amount of oil. Refer to the A/C Component Refrigerant Oil Capacities table.
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OEM oil capacity information

June 7, 2022

If you are installing an OEM replacement compressor in this example then it "should" contain 4.5 ounces of oil but if the compressor is not drained and the oil measured, the amount will not be known for sure.  Also, if an aftermarket compressor is being installed, there is no standard that exists in the industry regarding the amount of oil that might be shipped in a replacement compressor.  It might have no oil in it, a partial charge, or a full charge or even more than a full charge. To make matters worse, the OEM does not provide the total system capacity for this vehicle.
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A look at the new standard in mobile air-conditioning chemistry

June 6, 2022

Since Packard offered the first automobiles with factory air-conditioning in 1939, mobile cooling has been driven by R-12 and R-134a (both refrigerants in the Freon™ product family), followed by what is quickly becoming today’s standard, R-1234yf.
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Designing a Climate Control System for Electric Vehicles

June 3, 2022

How do engineers design climate control systems for electric vehicles
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Compressor lubrication tips

May 26, 2022

We will focus on lubrication information that is often encountered and how it can be interpreted incorrectly and result in the incorrect amount of oil being installed in a system.
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Robinair and MACS to certify 500 technicians

May 19, 2022

MACS member Robinair is partnering with the Mobile Air Climate Systems Association (MACS) to provide free Section 609 test prep webinars for training and certification for technicians this summer on June 16, July 13, August 17, and September 14.
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Compressor oil and the drain plug

May 17, 2022

When draining oil from compressors which have drain plugs, proper draining procedures call for the removal of the drain plugs and the unit drained from both the drain plug hole and the suction and discharge ports.
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The most important Tool

May 10, 2022

There is one essential tool we do not discuss enough that is the most important tool of all. TRAINING! No tool in your toolbox is going to work until you know the why, what, and when of how to use it.
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A new refrigerant for Trucks?

May 4, 2022

EPA has listed HFO-1234yf under the Significant New Alternatives Policy Program for Motor Vehicle Air Conditioning in Non-road Vehicles and Servicing Fittings for Small Refrigerant Cans
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Compressors 101

May 2, 2022

You are invited to attend a compressors 101 class I will be conducting next week at the MACS training facility in Lansdale, PA.  The title of the class is Behavioral Characteristics of Various Compressor Types.  It is happening live on Wednesday May 11 from 5:30 to 9:00pm
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Tools and Diagnostic Equipment for Mobile A/C Service

April 29, 2022

Remember it is up to the individual service company or technician to ensure they are following the requirements established in the location where they are working.
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Vacuum pump maintenance

April 26, 2022

As mentioned in last week's blog post, vacuum pumps require regular maintenance and frequent oil changes and  We wanted to provide information on the intervals, so we polled several vacuum suppliers.
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Earth Day 2022

April 22, 2022

MACS celebrates Earth Day 2022
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Your A/C season supply list

April 20, 2022

Unfortunately, something that is often absent from these A/C shopping lists is vacuum pump oil, and multiple containers of it should be included.
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The desiccant myth

April 12, 2022

There is a myth that exists involving A/C service work and driers that seems to come up from time to time.  I have encountered it when handling tech calls and have seen it come up in A/C forums. Read more to find out what it is.
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The value of a MACS membership

April 8, 2022

Someone asked me recently, “What’s the value of a MACS membership?” The question was an honest one. Why should anyone pay their hard-earned dollars to be a Mobile Air Climate Systems Association member?
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AirSept Announces the Passing of Founder and Automotive Entrepreneur Myron Stein

April 7, 2022

AirSept, a recognized leader in the automotive aftermarket for developing cost-effective, award-winning solutions for automotive repair, regretfully announces the passing of the company’s co-founder, Myron Stein.
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MACS 2023 Annual Training Event and Trade Show

April 7, 2022

MACS 2023 Annual Training Event is back on schedule for 2023! We will meet at the Gaylord Opryland Resort in Nashville, TN. February 2-4, 2023.
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No drier replacement, no compressor warranty!

April 6, 2022

Compressor manufacturers and parts distributors are adamant about driers being replaced when one of their compressors are installed. No drier replacement, no compressor warranty! 
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What is a receiver drier?

March 29, 2022

With A/C season just around the corner, this seems like a good time to provide some updated information on these units.  NOTE:  Receiver driers are sometimes called filter driers and accumulators are sometimes called accumulator driers.
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Replacement refrigerant confusion

March 22, 2022

There was a group of several refrigerants which were blends with a high percentage of R-134a and a smaller percentage of R-142 that seemed to be the most popular.
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Section 609 certification reminders

March 21, 2022

Currently, all technicians must show their certification card to purchase R-134a refrigerant in quantities of 2-pounds or more.
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MACS Compressor Class

March 17, 2022

Have you ever had questions about why certain types of mobile A/C compressors perform the way they do? Did you wonder who you could ask? Well MACS trainer, Richard Hawkins will be teaching his class Behavioral Characteristics of Various Compressor Types live at the MACS training facility on Wednesday, May 11 from 5:30-9pm.
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Talking refrigerant safety

March 15, 2022

Let's say I brought my car in to your shop with an A/C problem and described what was going on with it. You might ask me if myself or someone else had worked on it.  Right?
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What does a MACS Section 609 card look like?

March 10, 2022

MACS occasionally receives reports from the field of a technician being refused purchase of refrigerant for not having a proper Section 609 card. Usually this is due to the technician not producing the right card or the counterperson not understanding what a MACS Section 609 card looks like. What does a MACS Section 609 card look like?
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Refrigerant supply, pricing and safety

March 8, 2022

What I'm hearing about refrigerant supply and pricing this year reminds me of a similar period in the mid-2000s. It was springtime, just before the start of A/C season.  Supplies of R-134a were tight and the price had come close to tripling from the prior year.
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Heat pump basics

March 2, 2022

An internal combustion engine (ICE) is relatively inefficient, using only about a third of the fuel's heat energy (BTUs). The rest of the heat energy is “wasted” in friction, cooling and exhaust heat losses. Yet, the ICE’s wastefulness benefits the vehicle's interior heating.
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Refrigerant reminders

March 1, 2022

It could be a challenging year keeping adequate supplies of R-134a on hand and it will be more expensive.
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Meet MACS new president

February 28, 2022

Meet MACS new president, Peter Coll
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Checking for refrigerant contamination

February 24, 2022

A large percentage of MACS members have refrigerant identifiers and use of them on vehicles that come into their shop for A/C service prior to beginning any service work is standard procedure. However, there are a lot of non-MACS member shops who do not have identifiers and unfortunately are not aware of the potential issues which can be caused by refrigerant contamination.
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Correcting user error

February 15, 2022

As mentioned in last week's article, the first thing I did with the machine was check the pressure of the refrigerant in the tank.  It was extremely high (well over 400 PSI) indicating there was a refrigerant contamination problem. 
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The benefits of MAP-controlled thermostats

February 9, 2022

A customer driving a 2014 BMW 328i arrived at the college's 2nd-year electrical lab reporting his illuminated check engine light. The customer had no complaints other than the light. The vehicle had just over 82K miles showing on the odometer. A student (Phil) assigned to the BMW performed a review with a scan tool, and a single code (P0597 – Thermostat Heater Control Circuit Open) was present.
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Sometimes it is user error

February 8, 2022

I encountered a situation in the early days of recovery/recycling machines when they had just been introduced.  I had set up a machine about four months earlier when the customer purchased it.  I went to great lengths to cover proper operation of the unit and the shop owner even attended a certification clinic I conducted. 
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Air contamination in an A/C system can ruin your day

February 2, 2022

I had a memorable encounter with air contamination in the mid 1990s.  I was conducting a lot of retrofit clinics at the time and had recently acquired a demo refrigerant identifier which I took to those clinics. At one clinic, there was a technician who was extremely interested in the refrigerant identifier.  
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Read all about it!

February 1, 2022

Read all about it! MACS February 2022 digital issue of ACTION magazine is ready to view.
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MACS changes leadership

January 31, 2022

MACS is changing leadership. Elvis L. Hoffpauir, is stepping down at the end of January 2022 from his duties as MACS president and chief operating officer to enjoy retirement. Following a 42-year distinguished career at the Mobile Air Climate Systems Association (MACS), Elvis will transition to past president and association advisor.
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Heater Insight

January 25, 2022

Recently, a customer brought in a 2006 Honda Insight with a heater that was blowing cold but had no other vehicle concerns. A local garage had informed the customer the head gasket had failed; however, the owner felt a second opinion was necessary.
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Air contamination in mobile A/C systems

January 18, 2022

We covered a base line test conducted with 0% air contamination and provided pressure and temperature information.  This week we will provide pressure and temperature information experienced with 7.7% air contamination and 18.9% air contamination. 
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The effects of air contamination in an A/C system

January 11, 2022

If you perform an Internet search for effects of air contaminated refrigerant on automotive A/C system pressures, you’ll find many results.  This information leaves no doubt that air contamination of refrigerant in an automotive A/C system can affect system pressures and temperatures
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Variable output scroll compressors

January 5, 2022

This compressor has been around for quite some time and the vehicles it is used on are getting some age on them.  However, they still show up in shops with regularity and there still seem to be a lot of technicians that are not aware of the problem, diagnostic procedure and cure. 
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2022 is a great year for MACS training

January 4, 2022

Attend the best mobile air conditioning training classes available!
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When you don’t know about clutch wires

December 27, 2021

The conversation involved a clutchless compressor unit. A CSR who had sold one to a shop contacted me and said his customer (who was both the shop owner and technician working on the car) had just called him. There was a concern that the compressor didn't have a clutch wire.
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An overview of electronic variable displacement compressors

December 21, 2021

we have focused on electronically controlled variable displacement compressor operation and behavior.  It is important to have a good understanding of how these compressors operate and behave. This is because the percentage of vehicles coming into shops using these units is growing and will continue to grow.
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Helping your customer understand their A/C repair

December 16, 2021

To help service shop owners, MACS has created a 30-page consumer guide for your customers that explains how their car’s engine cooling system and air conditioning system works. “Getting to know your car’s air conditioning and engine cooling system,” details how these vital climate systems work and why they may require an extensive repair.
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Testing an electronically controlled variable displacement compressor

December 14, 2021

The A/C system was run with the vehicle's computer controlling the compressor.  When the heat loads were changed, there were noticeable changes in the duty cycle signal being supplied to the compressor.
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The pulse width modulated duty cycle signal

December 7, 2021

Several years ago, when vehicles using these compressors were just starting to show up at shops for service with some regularity, we were searching to find some detailed information about their behavior to use in clinics.  There was not a lot of it available, so we borrowed several vehicles and did some videos.  The following are some clinic slides produced from one of those videos.
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Bipartisan infrastructure package authorized $7.5 Billion for EV charging.

December 2, 2021

This week, the U.S. Department of Transportation (DOT) took the first steps in establishing programs for a national network of electric vehicle charging stations, as mandated in the bipartisan infrastructure bill passed earlier this year. 
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Virtual automotive software & electronics fundamentals boot camp

December 1, 2021

The boot camp will teach learners how to quickly create circuits and code software to build their own diagnostic tools or training aids. They will also learn how to control advanced vehicle systems for the purpose of diagnosing real (or simulated) problems. Automotive service professionals will develop skills to create simulators, demonstrators, and will also learn how simple electronic and software circuits can be used with the Scan Tool to develop circuits that can make complex diagnostics easier.
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Diagnosing electronically controlled compressors

November 30, 2021

When preparing to conduct diagnostics on a system using an electronically controlled variable displacement compressor, the diagnostic process needs to focus on four areas.
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Exploring electronically controlled variable displacement compressors

November 23, 2021

Electronically controlled variable displacement compressors (ECVDs) have been in use now for over 15 years.  However, there are a lot of technicians in the field who have very little knowledge about them and their operation.
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EPA releases Automotive Trends Report

November 19, 2021

Vehicle enthusiasts may want to check out the U.S. EPA's newly released Automotive Trends Report.
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Electronically controlled variable displacement compressors

November 16, 2021

what if" this system used an electronically controlled variable displacement compressor instead of the pressure controlled variable displacement compressor?   What would the results be?
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Disassembly and inspection of a seized compressor

November 15, 2021

MACS Tim Iezzi takes apart a problem compressor in this step-by-step video.
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You can get Tesla repair information

November 10, 2021

Find out how to use Tesla software for aftermarket repair
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Troubleshooting the “what ifs” in a mobile A/C repair

November 9, 2021

High side:  Likely somewhere around 130 psi (at an idle) & 140 psi at 1500 rpm.  Why? With only a 35% charge in the system, the compressor isn't going to be producing a lot of pressure.
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Meet MACS member, Tom Lech

November 8, 2021

Stationed in San Francisco, California, Thomas Lech has maintained a bustling business for almost three decades. Lech Auto Air Conditioning has been busy for 365 days a year from opening at 7 a.m. to closing at 7 p.m. for the last 27 years, with summertime only increasing the demand for the shop’s services.
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What do you know about the fixed displacement piston compressor?

November 2, 2021

What do you know about the fixed displacement piston compressor? 
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Bring the heat!

November 1, 2021

At this time of year, I often end up with an earworm in my head from a Canadian rock band … Summer’s going fast, the nights are growing colder. Then it’s the line everyone knows from something more mainstream … Winter is coming. It’s early September, and the leaves on some trees are already starting to change. Winter is coming.
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Tesla aftermarket repair information

October 29, 2021

NASTF has released new information on industry changing news! After 4 years of working together with Tesla, NASTF is pleased to announce that Tesla scan tool and service information is now available to the aftermarket. For the American and Canadian markets (Canadian version is in the final testing stages) things are changing rapidly that's why the National Automotive Service Task Force (NASTF) has brought their best experts to explain how to find, set-up, and implement this new information so you can add this new service opportunity to your shop.
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J1587/J1708 and J1939 data line diagnostics

October 27, 2021

Modern heavy-duty equipment is basically comprised of computers with operating units attached. In short, it is a multiplexing system that replaces traditional power distribution devices with ECUs that communicate electronically over the vehicle datalink.
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Compressor diagnosis

October 26, 2021

It is important to know the correct answer, but it is more important to know why it is the correct answer.  Please picture #4 for more information on that.
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The concept of superheat

October 19, 2021

We illustrated the concept of superheat in last week's article by boiling water and superheating steam in a moonshine still. This week we will apply this concept to refrigerant in an air conditioning system.  The still has been replaced with an evaporator. 
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Over 500 automotive scholarships available

October 14, 2021

The University of the Aftermarket Foundation (UAF) is now accepting scholarship applications for the 2022-2023 school year on its Automotive Aftermarket Scholarship Central website. Scholarships from UAF and more than 40 donor organizations are consolidated and easily accessible at AutomotiveScholarships.com.
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More on the behavioral characteristics of various compressors

October 12, 2021

Last week's article ended with a slide from my class at the MACS Training Event & Trade Show.  If you haven't already read that article, you may want to do so.  That slide had the following question in it: Finally, with a 30 to 32 PSI low side, why is the suction line temperature 65° F
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A beautiful day for golf

October 8, 2021

Here’s a Friday Flashback to Wednesday, September 29th, a beautiful day for golf. The MACS 41st annual golf tournament was played at Shingle Creek golf course in Orlando, FL.
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Airsept, Burgaflex and Sanz Kenway honored for MACS Trade Show best new products

October 7, 2021

Three MACS member companies received honors for their new products introduced at MACS 2021 Trade Show, October 1st at the Rosen Centre Hotel and Convention Center in Orlando, FL.
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Don’t try this at home

October 6, 2021

Don't try this at home! We do not recommend adding a machete to your mobile A/C tool kit. However, in Belize they do things differently. Sometimes necessity is the mother of invention.
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Behavioral characteristics of various compressor types pt. 2

October 5, 2021

So now it is time to provide the correct answer along with information on why it is correct and also information on why the others are incorrect.
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Thank you 2021 MACS Training Event Attendees

October 4, 2021

Thank you to all the attendees who travelled to Orlando, FL for MACS 2021 Training Event and Trade Show.
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Transit bus cooling system overhaul

September 28, 2021

Upon inspecting the 300,000-mile bus, we found several concerns likely contributing to the engine’s overheating situation
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Understanding and troubleshooting data lines on heavy-duty trucks

September 23, 2021

Understanding and Troubleshooting data lines on heavy-duty trucks will be presented byLarry Turay of LETCO Enterprises. In Larry’s Saturday morning class, attendees will learn how components and subsystem inputs and outputs can influence HVAC operations. 
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AEM Update: Snap application for off-highway R-1234yf

September 22, 2021

MACS will have a variety of heavy-duty and off-road presenters beginning at 8 am on Thursday, September 30.  One will be AEM Update: Snap application for Off-highway R-1234yf
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Behavioral characteristics of various compressor types

September 21, 2021

When faced with a challenging A/C system problem, knowing what type of compressor you are dealing with can help streamline the diagnosis process. 
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The cool kids ride air conditioned school buses

September 17, 2021

More and more school districts are requiring their school transport buses to be air conditioned.  On blazing hot days, high in humidity, it is a matter of comfort for riders.  In the era of COVID-19, filtration of the air is an important matter of safety.
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Cooling fan circuit analytics

September 16, 2021

What is Peter Orlando’s class Cooling Fan Circuit Analytics about? It all began decades ago as a mechanical fan attached to the water pump with and without a fan clutch.  And now it has evolved into an efficient complex electrical motor control of cooling the modern internal combustion engine.
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Understanding and diagnosing air conditioning

September 15, 2021

Most of today’s vehicles come equipped with electronically controlled A/C systems. Auto A/C systems have become more difficult to diagnose using the repair strategies learned from years of servicing R-12 and R-134a systems.
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A burned clutch is a symptom of another problem

September 14, 2021

Not much thought is given to compressor clutches until they fail, but they are extremely durable.  I have personally owned three vehicles that had between 200, 000 and 240,000 miles on them.  They all still had the original compressors and clutches, and they were still functioning perfectly.
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Facts to know about the compressor clutch coil

September 7, 2021

Checking the clutch air gap before installing a compressor is an important step in compressor installation. This is because of the possibility of a clutch air gap getting knocked out of adjustment due to rough handling or it being gapped incorrectly at the factory.  These issues of course can cause problems with clutch operation.  If detected and corrected before compressor installation, a lot of time can be saved.
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Back to school bus A/C

September 1, 2021

Since it’s September (and another school year is upon us), we’re going to look at what’s so different about school bus A/C as compared to the more common automotive-type systems.
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Mind the compressor clutch gap

August 31, 2021

One of the first things I was taught in my A/C training was to always check the clutch air gap prior to installing a compressor. 
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Who are MACS future leaders?

August 27, 2021

Nominations are now open for the 2022 MACS board of directors’ election. Are you ready to get involved and help shape MACS for the future?
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MACS Tesla project

August 26, 2021

MACS is working on a project, to collect A/C charge information for Tesla vehicles, and we need your help!
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Two clues to a condenser’s identity

August 24, 2021

There are two steps to determining what type of condenser is in a vehicle.
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What type of condenser is in that vehicle?

August 17, 2021

What type of condenser is in that vehicle? It's a frequent question in the mobile A/C industry.
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Mysterious servicing issue in R-1234yf systems

August 11, 2021

Recently a 2017 R-1234yf Honda system, with 72,099 miles, encountering a loss of cooling (slow leak) over time would not pass the equipment charge procedure and the production amount could not be charged. 
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Field study: Incorrectly installed condensers

August 10, 2021

I have handled numerous tech calls involving older GM trucks with incorrectly installed condensers.  In preparation for this series of MACS blogs, I discovered a salvage truck with one of these condenser repairs.  This gave me the opportunity to duplicate the incorrect installation and look for pitfalls and solutions.
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Finding right side up

August 3, 2021

Most condensers have different fittings on the inlet and outlet.  The locations of the inlet and outlet on most condensers will not allow lines to be connected incorrectly, even if the fittings do happen to be the same size.  Lastly, the designs of the mounts on most condensers prevent a unit from being installed upside down.  However, none of these characteristics apply to the condenser the technician had installed. 
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MACS Modern HVAC textbooks in stock for back to school

July 28, 2021

MACS Modern HVAC textbooks are in stock for back-to-school purchase.
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Did you install the condenser upside down and backwards?

July 27, 2021

The vehicle was a 1998 Chevrolet C 1500 truck with a 5.7 engine. The issue was excessive high side pressure. Almost as soon as the compressor clutch engaged, the high side pressure was over 400 PSI, and the high-pressure cut-off was turning the compressor on and off.
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Top three tips on orifice tube behavior

July 20, 2021

In the last four MACS blog articles we covered a lot of detailed information about orifice tube system behavior. We examined a system with a full refrigerant charge verses a 25% undercharge. Now it is time to condense it all down into three important takeaways.
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Truck A/C is a hot commodity

July 14, 2021

Look out on your local highway, and what do you see? Truckers getting the job done. They want their cabs to be cool in summer and warm in winter. They want the climate system to work right. There is no time for downtime. That is where we come in.
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Low refrigerant charge and the search for real data part 4

July 13, 2021

When we examined the pressure readings and vent temperature readings last week, there was nothing showing up that indicated any charge issues (even operating with the 25% undercharge).
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MACS Service Reports: a valuable member benefit

July 9, 2021

The MACS Service Report is a valuable MACS member benefit. Published nine times annually for dues-paying MACS members, MACS Service Report is an in-depth technical newsletter.
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We can’t wait to see you in person!

July 8, 2021

We are just a little over two months away from the rescheduled 2021 MACS Training Event and Trade Show! We can’t wait to see you in person September 30 through October 2 at the Rosen Centre Hotel in Orlando, FL. The golf tournament will be played on September 29 at the Rosen Shingle Creek Golf Course.
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Low refrigerant charge and the search for real data part 3

July 6, 2021

To place as much heat load on the system as possible, we turned the heat in the shop up on high and got it as hot as possible before beginning the test. When the temperature peaked at 89°, we began the test. We tried to keep it constant, but all the heat being generated by the engine in the test vehicle caused it to inch upward by 2.5° before the second test was concluded.
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A/C for E-trucks

July 1, 2021

Are you ready for E-trucks? Find out in the July/August 2021 issue of MACS ACTION magazine.
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Low refrigerant charge and the search for real data: part 2

June 29, 2021

The purpose of the test was to run an orifice tube system with a full refrigerant charge and then with a 25% undercharge and compare pressure readings and temperatures at strategic points in the system.
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What’s the word on R-134a price & supply?

June 24, 2021

The email questions are already coming in, and they go kind of how you’d expect: What’s going on with the price of R-134a? Is there going to be a shortage of R-134a supply?
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Low refrigerant charge and the search for real data

June 22, 2021

I had read about how low refrigerant charges could increase compressor operating temperatures and decrease the amount of oil flowing to compressors, but I had never been able to find results from any tests. After discussing this with MACS, we decided to do some testing to get some real data.
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Refrigerant capacity and mobile A/C service: part 2

June 15, 2021

One of the most frequently asked questions on tech help-line calls concerns refrigerant capacity: How much refrigerant is in that mobile A/C system, and have you checked to be sure the refrigerant is pure?
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Mobile A/C training when you want it!

June 14, 2021

If you’ve been too busy or the COVID-19 situation has made it difficult for you to attend mobile A/C training MACS has the solution.
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In this heat, check the back seat

June 9, 2021

in this heat, check the back seat
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Refrigerant capacity and mobile A/C service

June 8, 2021

One of the most frequently asked questions on tech help-line calls is: How much refrigerant is in that mobile A/C system, and have you checked to be sure the refrigerant is pure?
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Robinair sponsors free Section 609 test prep webinar and test for 500 technicians this summer

June 7, 2021

Robinair sponsors free Section 609 test prep webinar and test for 500 technicians this summer
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Electrification and climate control technologies: Are we prepared?

June 3, 2021

A recent survey from CarGurus suggests consumer interest in purchasing an electric vehicle (EV) has doubled in the past three years.
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Focus on the condenser!

May 31, 2021

In last week's article, we focused on applying temperature testing to an evaporator in an orifice tube system. In it we illustrated how and why a low liquid level in the evaporator can cause a large temperature differential between the inlet and outlet. We also indicated how and why raising the liquid level will cause the temperature differential to decrease. Now it is time to focus on the condenser.
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Show me your MACS 609 card

May 26, 2021

When you purchase refrigerant in quantities of two pounds or more you must show your Section 609 card.If you are Section 609 certified through MACS between 1991 and May 2021...
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Temperature testing detective work: The search for a diagnosis

May 25, 2021

Last week we closed our blog post with a discussion about an orifice tube system which had an evaporator outlet temperature that was about 20° warmer than the inlet. We mentioned that this could be an indication of a restricted orifice tube or a refrigerant undercharge. In applying this to diagnostics, it is important not only to understand what this represents, but also why.
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What is your temperature testing data telling you?

May 18, 2021

If air conditioning systems were transparent where we could see inside them, then diagnostics would be faster and easier. We could look at the systems and see things right away that affect system operation, like restrictions and liquid levels in evaporators and condensers.
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Do you have the essential tools for success?

May 17, 2021

Using the correct tools to service and repair vehicles is so important that the Society of Automotive Engineers (SAE) creates standards for some service tools to meet. Requirements for their use by service professionals is included, as well. Some examples include refrigerant recovery and recycling machines, refrigerant identifiers and leak detectors.
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AIM: EPA’s HFC Authority Is On!

May 14, 2021

On December 27, 2020, President Trump signed into law the Consolidated Appropriations Act, which at $2.3 trillion is one of the largest spending bills in US history. It combines $600 billion in COVID relief with $1.4 trillion in twelve different appropriations bills. One of them is the AIM Act.
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Temperature Matters

May 11, 2021

In addition to having good contact with connectors and getting accurate readings, there are some other important things to remember when doing temperature testing.
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Pass the temperature probe

May 4, 2021

The first step is to run the A/C system for a few minutes to let it stabilize. Then both probes should be connected side by side at both points that will be temperature tested in the system. For example, if you were testing the temperature drop across the condenser, this would need to be done on both the discharge line and the liquid line.
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Are you using the right tools for mobile A/C repair?

April 30, 2021

Your shop’s R-134a recovery/recycling/recharge (R/R/R) machine is in well-maintained condition. You have an R-1234yf gauge manifold set and an R-1234yf machine is on order; should arrive shortly.
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Contact counts in temperature testing

April 27, 2021

Proper contact is vital when connecting to A/C lines using the contact type temperature thermometers. To determine if I am getting good contact, I always like to place both connectors side by side on the same line and observe the temperature readings.
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MACS Mobile A/C Update Webinar Now Available On Demand

April 22, 2021

Every year the Mobile Air Climate Systems Association creates a special mobile A/C update clinic to help working technicians keep up with the rapidly changing mobile A/C service and repair...
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Tips for taking your mobile A/C system’s temperature

April 20, 2021

The contact type units do indeed have a high degree of accuracy, but precautions must be taken when using them (especially connecting to lines) to ensure the accuracy. Otherwise, it is possible to get readings that are easily 5° to 10° off and that can lead to an incorrect diagnosis.
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The pressure is on

April 19, 2021

By appearance, radiator caps seem to be a simple device. Yet, many technicians do not understand the cap’s real function
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Temperature testing accuracy

April 13, 2021

Temperature readings can be easily used to determine if an orifice tube system might be undercharged, and they can also be used to charge an orifice tube system. But if the readings are not accurate, all they are going to do is cause you problems.
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Then things got complicated!

April 9, 2021

It was a 2013 Camaro. The complaint was poor cooling and the temp really would not change when you switched it from heat to cool. In diagnosing the job, the technician found the blend door was stuck to where it was blending heat. Until it was pulled out, the tech was not sure if it was a bad actuator or door.
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Avoiding an oily situation

April 6, 2021

If you own a mobile A/C repair shop this is when you start to gear up for it, by replenishing your parts inventories and an important segment of those inventories is compressor oil.
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Preseason Training: A Service Manager’s Guide to Preparation

April 1, 2021

Proper training can limit the time period that any given mechanic spends in the novice stages of their career, and it may help them advance to expert performance levels in an expedited time period.
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How to deal with a compressor oil viscosity change

March 30, 2021

dealing with a catastrophic compressor failure where system flushing and component replacement removes all the oil from the system, then it is a matter of just installing the correct quantity of the oil that is specified for the replacement compressor.
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Texas Truck A/C thrives for 25 years

March 29, 2021

As Texas Truck A/C owners, employees, and customers celebrate the company’s 25th anniversary of being in operation, this business demonstrates what it means to not only survive for 25 years but to thrive.
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Help wanted!

March 26, 2021

MACS member repair shops are hiring
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ParkSmart Bunk A/C System Freightliner P3 Cascadia

March 24, 2021

The ParkSmart auxiliary HVAC system has been offered to replace the standard auxiliary HVAC unit.
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Why does the replacement compressor use different oil (than the original unit)

March 23, 2021

That is viscosity and specifically why a replacement compressor might use a different viscosity oil than its OEM counterpart.
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Does the compressor contain oil?

March 17, 2021

A question that comes up frequently on A/C tech lines is: Does the compressor contain oil and if so, how much?
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Marks Air celebrates 50 years of mobile air success

March 16, 2021

MACS member Marks Air Inc. celebrates 50 years of being in business.
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Tank full of air!

March 15, 2021

The problem is usually caused by excessive air in a system, and since too few shops use a refrigerant identifier, they don’t know when these problems come up, nor how often they are solving problems by doing this.
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What is MACS Membership?

March 12, 2021

How do I become a MACS member?
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Time to plug into EV training

March 10, 2021

Read any automotive publication or website, and you will see numerous stories from all the big automotive manufacturers and quite a few shiny new start-ups about vehicle electrification.
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How much oil “goes” in the compressor?

March 9, 2021

There is also an additional step which is required in the oil draining process with this unit. That step is that the suction damper needs to be depressed to allow proper ventilation when draining one of these compressors.
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Helpful tips to register for MACS online training clinics

March 5, 2021

Helpful tips on how to register for a class on the MACS website
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“Balancing” oil balancing

February 23, 2021

What should we do if performing an oil balance and only 1/4 oz of oil drains from the original compressor
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Let everyone know you are Section 609 certified

February 22, 2021

Section 609 work t-shirts in black featuring the new MACS logo.
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Caveman to Mr. Cool

February 18, 2021

Over 300,000 years ago, modern man began walking the earth relying heavily on his five senses-- especially sight – to hunt, find joy, and avoid danger. In 1914, Garrett Morgan, who decided it was important to protect man’s eyes during hazardous situations, developed what we know today as ‘safety’ glasses.
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Fix it correctly the first time

February 15, 2021

A cooling system classroom lesson By Christopher J. Holley, MACS Contributing Editor A 2017 Accord with an overheating 2.4L engine arrived at our college lab. The customer had a limited...
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A Change in Temperature

February 10, 2021

Using a contact thermometer, they quickly discovered 50° on the suction line at the expansion valve, and down at the compressor it read 96°. Along any length of hose or tube, there should be very little change in temperature.
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Compressor Oil: When is it enough?

February 9, 2021

But how do we know that a system has the correct amount in it to start with?
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MACS Board of Directors Elects 2021 Officers

February 8, 2021

The board of directors of the Mobile Air Climate Systems Association (MACS) met virtually Friday, February 5, 2021, and elected officers for the year. Andy Fiffick of Rad Air Complete...
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Stop by macsmobileairclimate.org for a visit

February 5, 2021

Visit MACS at macsmobileairclimate.org
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Doing the repair right

February 4, 2021

By Richard Hawkins, MACS Contributor The focus in the two previous weeks articles on the Chevy Tahoe was on what went wrong and what should have been done to correct...
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The beginning of a New year, new MACS!

February 1, 2021

The Mobile Air Conditioning Society has rebranded to become the Mobile Air Climate Systems Association (MACS). During a year-long project, the MACS board and staff worked with the Blue Door...
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Tales from the helpline: When they don’t know, what they don’t know!

January 26, 2021

By Richard Hawkins, MACS Technical Contributor Last week, my topic of discussion for the MACS blog was a tech call about an A/C system which was plagued by a huge...
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How much compressor oil is too much?

January 19, 2021

By Richard Hawkins, MACS Technical Contributor A lot of interesting calls are encountered when working on an A/C tech help line and a large percentage of them involve lubrication issues...
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Let me tell you a story…

January 12, 2021

I conducted my first A/C clinic in 1991 which of course was 30 years ago. That was right along the time when things were getting geared up for the transition from R-12 to R-134a and was a very interesting period.
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OSHA and HazCom citations

December 14, 2020

By Charles Ayers, CCAR By the time you read this, the Occupation Safety and Health Administration (OSHA) will have released its “Top 10 Most Frequently Cited” list for fiscal year...
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Disinfecting of vehicles during COVID-19

November 10, 2020

By Ward Atkinson, MACS Technical Advisor, & Bill Hill, GM Retired Recent comments from government agencies on the COVID-19 virus issue indicate that even when a vaccine is available, our...
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Hazmats: Why should I care?

September 21, 2020

Trivia question: what do R-134a, Lithium Ion batteries, air bag modules, and used fuel system components all have in common? Aside from the fact that these are all in-use in today’s vehicles, they are all also classified as Hazardous Materials (i.e. hazmats) by the U.S. Department of Transportation (DOT). The same holds true for these products in Canada, where the governing body (Transport Canada) has similar designations for what they call ‘Dangerous Goods’ (i.e. hazmats).
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Back to basics

September 9, 2020

There is no doubt that when it starts getting hot outside, your shop gets slammed with customers asking for help with their A/C systems. Same thing happens here at MACS, except we get slammed with A/C tech support calls.
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Understanding data lines (Part I)

September 8, 2020

By Larry Turay Data lines and multiplexing have been with us in the heavy-duty world since 1990. The increased use of ABS, electronic ICUs, and automated transmissions to name a...
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Are you a diagnostic detective?

September 3, 2020

By Pam Oakes, SME automotive professional If you consider yourself a diagnostic detective see if you can solve this cooling system mystery before the end of the article! Cooling Corner:...
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Spend some time with MACS president and coo Elvis Hoffpauir

July 24, 2020

Hello, and Welcome to MACS Worldwide’s YouTube Channel. We’re glad you’re here! Elvis Hoffpauir Pioneer Experience MACS History! Elvis Hoffpauir, MACS president and chief operating officer, was presented with a...
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MACS Live Chat (John Duerr & Steve Schaeber discuss A/C Leak Detection Tracer dye & COVID-19 in NYC)

May 28, 2020

Hi everyone, and welcome to another MACS Live Chat, hosted by Steve Schaeber, manager of service training and technical editor for MACS publications like ACtion Magazine and the MSR (MACS...
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Stop complaining about the technician shortage…

April 8, 2020

…and DO SOMETHING ABOUT IT! By Elvis Hoffpauir C.O.O. MACS Worldwide That was the principal message from Peter Meier, Director of Training at Motor Age. Peter, along with MACS Technical...
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Helpful tactics to minimize the spread of Covid-19 in your service and repair shop

April 7, 2020

By Bill Snow, Radair Complete Car Care, Cleveland, OH With today’s concern about being exposed to COVID-19 shop owners need to take additional steps to protect their team members and...
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