Addning heat strips to heat pump AC units
I have two ac/heat pumps, both same models on my 07 Discovery. The units are running w/o issue BUT I'd like to save my propane & install some heat strips. Has anybody done this before? I have locat...
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Everything I write here assumes your RVP/Coleman heat pump is the same as my 15 kbtu RVP/Coleman heat pump. Mine came from the factory with the aux heat strip installed. If the creators had executed the controls differently it would be a good option. As they did it, it's IMO not worth dealing with.
The aux heat strip provides 5,600 btuh, equivalent of a 1,640 watt heater. By comparison, the specs say the heat pump produces 12,700 btuh in standard test conditions with the outside temp 47 degrees.
The control of the aux heat strip is done completely in the roof unit. The thermostat doesn't know it exists. The roof unit has an outside temp sensor that cuts the heat pump off at about 40 degrees. If the heat strip is installed, the power that is cut off from the compressor is routed to the heat strip. With that background, here are the unintended consequences:
1) The roof unit forces the fan to run on high whenever heat is selected. High fan is IMO unnecessarily fast for use with the heat strip and they should be running it on low so the outlet air feels warmer and the noise level is lower.
2) Since there's no way to force the heat strip on, you can't "de-stink" it at the beginning of the season or before a trip. The result is that when you finally hit a cold day and the strip activates, it stinks like heck from not getting used for a long time, and you want to open the windows to get the smell out. Catch-22!
Having too much time on my hands I modified my upper unit, adding a switch to force the heat strip on (for pre-season de-stinking), and at the same time force the fan to low speed. Without this change, I'd never want to use the darn thing.
The aux heat strip provides 5,600 btuh, equivalent of a 1,640 watt heater. By comparison, the specs say the heat pump produces 12,700 btuh in standard test conditions with the outside temp 47 degrees.
The control of the aux heat strip is done completely in the roof unit. The thermostat doesn't know it exists. The roof unit has an outside temp sensor that cuts the heat pump off at about 40 degrees. If the heat strip is installed, the power that is cut off from the compressor is routed to the heat strip. With that background, here are the unintended consequences:
1) The roof unit forces the fan to run on high whenever heat is selected. High fan is IMO unnecessarily fast for use with the heat strip and they should be running it on low so the outlet air feels warmer and the noise level is lower.
2) Since there's no way to force the heat strip on, you can't "de-stink" it at the beginning of the season or before a trip. The result is that when you finally hit a cold day and the strip activates, it stinks like heck from not getting used for a long time, and you want to open the windows to get the smell out. Catch-22!
Having too much time on my hands I modified my upper unit, adding a switch to force the heat strip on (for pre-season de-stinking), and at the same time force the fan to low speed. Without this change, I'd never want to use the darn thing.
