Originally Posted By: kluce
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[quote=“jfarsetta”]I also go by 15 to 20 degrees. this came from a reputable HVAC contracting firm who have been around for a while. I look for 20 degrees or damn close to it… I also let the unit run for about 30 minutes before taking the readings[/quote
30 min is a long time to run the A.C. I normally put my guages on to check pressures which needs to be done first before any temp drop can be done and then check for temp drop which is 5 minutes later.
I don't do temp drop unless I find something that directs me to that. When I was a HVAC service tech, I would do temp drop to check for efficiency. If the coil is plugged, then a pressure drop is needed not a temp drop reading.
If you think I am wrong on this, let me know. I've had some inspector disagree with me on this but they couldn't tell me why.
The inspectors I ran into don't have freon gauges or no EPA card to check freon. I wonder what percentage of inspectors don't have this. What do you think? ![icon_biggrin.gif](upload://iKNGSw3qcRIEmXySa8gItY6Gczg.gif)