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Off Road

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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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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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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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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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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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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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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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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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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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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