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.Read Article >
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.Read Article >
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?Read Article >
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.Read Article >
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.Read Article >
What do you know about the fixed displacement piston compressor?
November 2, 2021
What do you know about the fixed displacement piston compressor?Read Article >
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.Read Article >
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.Read Article >
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.Read Article >
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.Read Article >
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.Read Article >
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.Read Article >