Home Improvement → [HVAC] Goodman 2 Stage HP Defrost

Too low or too high subcooling affects both cooling and heating efficiency. Keep in mind, many manufacturers will allow ± 2-3°F when taking readings. Most importantly, when taking temperature and pressure readings, having accurate instruments is critical. Otherwise, the readings are useless. Using today's advanced digital manifold gauges (Testo, MasterCool, Fieldpiece, Yellow Jacket, etc.) are the most reliable and accurate method for measuring superheat and subcooling.

I would not get too caught up with the line set length, unless the line set is unusually long (80' or longer). In your case, charging the system using subcooling is perfectly acceptable.

Thanks, Tex.

So from your experience, how much of an impact would having 7* subcooling on High speed, where the manufacturer's spec calls for 8-10*?

This is assuming the readings were 100% accurate: he read the gauges correctly, they were calibrated and the digital clamp on thermometer was recording the true gas temperature, etc? As you point out there will be some inaccuracies in the measurements, but lets call it an ideal world for discussion.

I am just trying to get a feel for how sensitive performance is VS subcooling and I appreciate there is probably not a big performance hit. Just curious .