Need Heat Pump advice

[Joe Funderburk, CMI]

Did 3 small "carriage homes" today (warranty inspections). All about 1000 SF downstairs units with 36 BTU heat pumps.

Measured heat output at vents in normal mode at about 86 F. Switched to Emerg. Heat mode and the temp dropped to about 83 F.

I'm used to seeing the temperature outputs closer to 100 F. and the emerg. heat mode being higher than the normal mode.

The outdoor temperature was about 35. Anyone see an issue here? All 3 units (Lennox) were same make and model and age and all behaved about the same. Same builder for each unit.

[Charley L. Bottger]

Originally Posted by jfunderburk

Did 3 small "carriage homes" today (warranty inspections). All about 1000 SF downstairs units with 36 BTU heat pumps.

Measured heat output at vents in normal mode at about 86 F. Switched to Emerg. Heat mode and the temp dropped to about 83 F.

I'm used to seeing the temperature outputs closer to 100 F. and the emerg. heat mode being higher than the normal mode.

The outdoor temperature was about 35. Anyone see an issue here? All 3 units (Lennox) were same make and model and age and all behaved about the same. Same builder for each unit.

I told you so take the cover OFF use the amp meter see if the strips are working. Yes 86 is to cold for in the normal heat mode

[Joe Funderburk, CMI]

The strips are working (it was blowing in the 80s).

I'm just used to seeing the temperature rise with the unit in EH mode. Also used to seeing both temps (normal and EH) higher than mid 80s.

Everyone agree? I'm thinking of referring it to an HVAC tech so he can take the cover off and check the heat strips.

[Charley L. Bottger]

Originally Posted by jfunderburk

The strips are working (it was blowing in the 80s).

I'm just used to seeing the temperature rise with the unit in EH mode. Also used to seeing both temps (normal and EH) higher than mid 80s.

Everyone agree? I'm thinking of referring it to an HVAC tech so he can take the cover off and check the heat strips.

Whoose

[Joe Funderburk, CMI]

Called an installer friend this a.m. He said it sounded normal. EH mode would be less than normal mode. But when you bump up the temp by several degrees in normal mode, the heat strips and condenser run at the same time (aux. mode) and that temp would be closer to 100 F. he said.

[David A. Andersen]

What size heat banks were they using, and how many?
It's printed right on the heater's just inside the access panel cover.

What was the amperage draw on the electric heat circuit?
V * A = Watts / 3.412 = BTU/hr

The heat pump should be set up so that it can operate in the electric heat mode only (especially in extremely cold/humid weather). Just like the weather we're having right now.

You simply have undersized electric heaters in this application.

There are numerous top end equipment modifications available to stage the banks to operate only when needed.

With an outdoor air temperature of 35°, a heat pump should not be producing more heat than the electric heat banks.

What happens when the heat pump goes into defrost? It has to fight the air conditioner on top of cold weather! I don't like the sounds of that design. It's all about a matter of options, and system design for the application.

I'm sure that you cannot answer the above questions because you stated previously (in another post) that you did not open the panels because they were screwed shut.

If you took a look inside, you could answer these questions and we could give you an answer to use in your inspection report. There is a high probability that when you call this out in your report, you will be met with extreme resistance from the HVAC contractor because you have insufficient data to refute their design calculation.

If you do not collect information by opening up a panel. If you do not obtain the values to determine the heater's output (which is a simple mathematical equation), I suggest that you do not report anything about this because this is beyond your home inspection standard of practice in accordance with your state law. Evaluation and performance of the HVAC equipment is not the responsibility of the home inspector.

[Joe Funderburk, CMI]

Thanks David. Very informative.