Heat Pump(s) or control unit

[medjoolguy]

I have two 15,000 btu 48000 mach 15 heat pump / AC made by Coleman Mach. Both units put out cold air with no issues. My control panel allows the following choices a) heat / ac (gives you a range for turning on the AC or the heat and does so automatically) b) heat only, c) AC only.

In the heat mode the control panel allows you to choose heat pump or LP.

When I choose heat pump (on both units) I get NO (ZERO) heat no matter how long the unit runs. Fan runs the whole time circulating the air.

I can tell when I cycle back to AC that the compressor turns on when in AC mode and then is not on when in heat pump mode. I don't think that is the way it should work... i.e. in order to generate heat in heat pump mode I believe the compressor has to run.

I'm suspecting that it is something to do with the LCI control panel and/or the way it was all installed? I never tried the heat until now (I live in Houston).

Anyway...aside from taking it into the dealer when I get back home...figured I'd see if anyone had a similar issue.

I've read many posts where folks discuss the reversing valve....and I suppose that could be what is wrong with both units...but I suspect that the fact that the compressor is not coming on with either unit combined with the rare chance that both would have a reversing valve issue...leads me away from the valve not working.

Any thoughts are appreciated.


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[fischer]

What year is your coach
Col mach has 2 year warranty

[dougrainer]

From RVP

What is the temperature range for my Heat Pump?
The Coleman-Mach heat pump is an effective heat source, as long as outdoor temperatures are above 45°F. Below 45°F, there is not enough heat outside for the system to absorb, and efficiency drops. With a lack of heat, you will run into a freeze up situation that will shut down your compressor, but leave the indoor blower running. We recommend that, if you know your outdoor temperatures are going to be below 45°F, simply heat the application with the LP furnace until the conditions are more ideal for the heat pump.

[dougrainer]

from RVP

When your thermostat is in the “Electric Heat” mode, if the set temperature is five or more degrees above what it shows as the room temperature; the thermostat will consider this too much of a load for an electric heat source and bring in the furnace to assist. The furnace will continue to run in this case, until the thermostat is satisfied. When the room temperature starts to drop again, the thermostat will try to proceed as normal, with just the electric heat (unless the difference between set point and room temperature reaches five degrees again).
PLEASE NOTE: Some of our thermostats will not run your electric heat and gas heat simultaneously. They will shut down the electric heat in order to bring in the gas heat.
Multiple consecutive calls for the furnace in the “Electric Heat” mode, can cause the thermostat to lock out the electric heat function for approximately two hours, triggering the furnace only when it needs heat. For more information on the Lockout function of the thermostat,

[dougrainer]

You don't state temps and what you set the HP mode at. That said, RVP HP's IF YOU SET MORE THAN 5 DEGREES ABOVE THE INTERIOR TEMP, the HP's will NOT heat. So if the RV is 60 degrees and you set at 66 or above the HP's will not come on but your LP furnace will come on. Once the interior temp is within the 5 degree range the roof HP's will come ON. If you want the HP's yo heat up the unit, you must set the temp in 5 degree increments-----unit is 60 degrees, you set at 65, once 65 is met, you set at 70 and so on until your RV is at the temp you want. Doug

[MrWizard]

i'm not a heat pump expert
but
did you try heat & LP on either unit ?

did you try LP heat from furnace warm up the RV then switch to heat pump

what is the outside temp, 40* used to be the heatpump limit
but users on here say new models work to around 30* now

below their capacity limit you get not heat, since the unit is the roof or in the basement and sense ambient temperature , could be some will refuse to run in heat pump only mode

[1492]

Moved from Forum Posting Help and Support

[Sea_Six]

If the reversing valve is shot (like mine) I hope you have better luck finding a replacement.

Mine is stuck and it's now just an AC unit (no heat).

[sch911]

What was the temperature outside when you tried this?