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Old 08-31-2018, 10:52 AM
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Diseasel300 Diseasel300 is offline
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Quote:
Originally Posted by Maxbumpo View Post
Here's a nice video explaining how to do some basic system diagnosis using temperature readings.

https://youtu.be/wF37ihNBXq8
That's a very good video explaining how the temperatures relate to efficiency of the system. MVAC is very similar to HVAC, but often operates at much lower superheat settings and much larger ∆T.

It's important to note when testing MVAC systems that the doors/windows need to be open so that the system is cooling ambient air, not recirculating the cabin air.

As a comparison to that video using my own car earlier this summer:

With an ambient temp of 102˚F, I had a difference of 41˚ across the condenser (139˚ discharge temp), 40˚ across the evaporator (62˚ discharge temp), and a superheat of around 4˚ at the return line to the compressor (65-66˚ line temp). I took all those measurements for a friend trying to get the charge right on their own car with an unknown quantity of refrigerant already in the system, but suspected to be low. I don't have a fancy CPS tester like the video creator did, I used a pair of Type K thermocouples attached to BK meters at work.
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