In heat mode. The outdoor coil is the evap. So the VS blower inside isn't causing the high low side pressure.
Outdoor Temp Indoor Temp Rise
65 degrees 33 degrees
60 degrees 31
55 degrees 29
50 degrees 27
45 degrees 25
40 degrees 23
35 degrees 21
30 degrees 19
25 degrees 17
20 degrees 15
15 degrees 13
This is a generic chart. If you have an oversized indoor unit, the temperature rise will typically be a couple of degrees cooler. Different brands vary some as well. But it is a good starting point for a heat pump with the strip heat help off.
Note: There does not seem to be a way to make the columns line up right.
Remember, Air Conditioning begins with AIR.
Yeah the concept of heat pump is neat, in heat mode outside unit is Evap. Yesssir !
Thanks for the chart Kevin. This absolutely will help me diagnose heat pumps better (with elements off). I just got to learn so much its unbelievalbe ! Infact there is so much to learn in this industry, I love it!
Next is to master boilers...we don't have many here, well I say maybe 25-30 percent, but everytime I get a call to do a pm on a boiler it makes my day
The problem with relying on temp rise alone is that the airflow greatly varies - you can't assume that the installer set the blower speed correctly.
Superheat/subcooling, compression ratio, indoor airflow, and amp draw theoretically can tell you exactly what's happening in the system.
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if you take ampdraws, pressures with panels off of condensing unit,ive gotten some crazy pressures and draws.air flow across coil is important right?pros i am asking your opinion
hvacmac7, you are right. once the panel is off, the pressures do generally go high. I never take pressures with panels off. I think its the air volume that goes through the coils is not enough and hence impacting the pressures in the coils and amping of the compressor.
*air flow and air volume are two different measurements*
Think about it. Where does the airflow go when you take the panel off? Why do you want the airflow to draw across the coils? Remember what is required for the vapor-compression cycle to work.
Originally Posted by hvacmac7