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 >
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.Read Article >
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.Read Article >
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?Read Article >
Two clues to a condenser’s identity
August 24, 2021
There are two steps to determining what type of condenser is in a vehicle.Read Article >
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.Read Article >
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.Read Article >
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.Read Article >
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.Read Article >
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.Read Article >
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.Read Article >
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.Read Article >