Optimizing operation of heat pump for efficiency

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Yes it could but I don’t think that’s it. The system needs to be able to run at 100% output at 60 degrees outside temp. Do the math at the projected flow rate and known delta T and calculate btu output.

I don’t know if I trust the heating performance chart. Why would the system efficiency increase as the return temp increase???

Really you need to be able to measure face velocity and static pressure.

I did some quick math. This morning it was about 20 deg F outside.

I'm keeping an indoor temp of 67. I saw temperatures when the unit was running full-out of about 104 deg. That's a delta of 37 degrees.

At 20 deg F outdoors, and 70 deg F return temperature (close enough to my 67), it should be delivering about 51000 btu/hr.

Using q = CFM x 1.08 x DT, this calculates a flow rate of 1276 cfm. I can't be entirely sure, but I think only one zone was open at that time, so this is consistent with the 1300 cfm I measured with static pressure yesterday.

Optimizing operation of heat pump for efficiency
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Data is consistent. And saying your SP is high but not off the charts. I’m taking the position that at or under max spec they system should not shut it self down.