Control for Heat pump + backup elements

[KesTheHammer]

If I have a heat pump with backup elements, what would be the best (easiest/most reliable) way to control it, so that automatic changeover happens if the heat pump fails?

I thought of just doing it with different setpoints, but the elements will probably then work more than is energy efficient.



Kestell Laurie
South Africa

 

[Ziggypump]

Isn't this a control issue? I would think there would be some sort of contact showing the heating portion of the heat pump is functioning properly. Assume water-to-air heat pump, if the condenser is not working, then the heating isn't working, then default to backup heat.

If you're looking for something after market, maybe some duct temp stats; one in the return and one in the supply. When the unit calls for heat and the supply air temperature is less than 1 degree more than the return, this could activate the backup.

Now my understanding of the question isn't so much that the heat pump isn't working, as the compressor and refrigerant cycle isn't working. I view the entire unit (fan, coil, condenser) as the heat pump, so if the heat pump isn't working, then the fan isn't working, and a supplemental heating element isn't going to do squat. I would think of this in the controlling of the primary/secondary heating of your system.