Heat pump switches from electric to LP?

[FixerCQI]

Try operating the unit on manual low speed fan. If the thermostat sensor is in the ducting and not on the wall, the amount of heat being produced may be better able to heat the lower volume of air passing by it. Then it won't switch to emergency heat as often.
Another point is that the front unit has a much larger area to heat with more windows (as mentioned) . The bedroom also has two (I assume) warm bodies helping to keep it warm.

[wildtoad]

Mine ( Dometic ) will auto switch to furnace if the outside temp is too cold for the hp to work properly. It is a “feature” of the system so make sure to have propane available.

[Betr2Trvl]

If the temp is going to go below 40 overnight, I just set my thermostat to gas heat when we go to bed. No reason trying to make the heat pump run when it's not going to work efficiently and it's going to cut over to the propane furnace anyway, and I really don't want to loose 5 degrees either! Our heat pump also starts making a racket at the point it's really not putting out warm air as well........

In the case, where it is cold overnight, but not below 40, I close the forward HVAC vents when we go to bed, which forces more air back to the bedroom, as well as not putting as much warm air on the temp sensor in the front so the heat pump will run a bit longer putting warm air to the bedroom.

Regards

[Hikerdogs]

Originally Posted by happyretired

Mine kept doing the same thing, and after having it checked out, it was to have a frozen reversing valve. Since the roof units are NOT servicable, the whole heat pump/ac had to be replaced. Big Bucks!

A "frozen" switching valve is very suspicious. About the only things that can keep it from operating are physical damage, no signal to the solenoid coil, or a burnt out coil. While a damaged valve isn't serviceable the other 2 causes are.

A damaged valve is the least likely of the scenarios. It would have to have happened prior or at the installation, or as the result of an accident. In the case of damage at or prior to installation it shouldn't have worked from day one. If it was the result of an accident there should physical evidence of something hitting the unit hard. Something striking the unit hard enough to damage the valve would also show catastrophic damage to other components.

We had a similar problem with one of the units on our 2013 Adventurer. We took it to 2 dealers and the Winnebago factory. All made the same conclusion that we needed a new $1,600.00 AC unit. I wasn't satisfied with their answer due primarily to the fact that the unit still worked fine in the cooling mode, it just wouldn't switch to the heat mode.

I finally went up on the roof with my trusty muiltmeter and did a little diagnosis. It turned out there was no signal to the operating solenoid regardless of the settings at the thermostat. At that point I suspected the control module under the AC shroud.

I called the Airxcel technical hotline and explained the situation to one of their technicians. He agreed with my diagnosis and sent me a new control module at no charge. I installed the module and everything has worked fine since.

The control modules are available directly from Airxcel or from a dealer at a cost of about $250.00. In our case it was provided free of charge since it had been an intermittent problem while the coach was still under warranty.

[shiggs68]

Originally Posted by Hikerdogs

A "frozen" switching valve is very suspicious. About the only things that can keep it from operating are physical damage, no signal to the solenoid coil, or a burnt out coil. While a damaged valve isn't serviceable the other 2 causes are.



A damaged valve is the least likely of the scenarios. It would have to have happened prior or at the installation, or as the result of an accident. In the case of damage at or prior to installation it shouldn't have worked from day one. If it was the result of an accident there should physical evidence of something hitting the unit hard. Something striking the unit hard enough to damage the valve would also show catastrophic damage to other components.



We had a similar problem with one of the units on our 2013 Adventurer. We took it to 2 dealers and the Winnebago factory. All made the same conclusion that we needed a new $1,600.00 AC unit. I wasn't satisfied with their answer due primarily to the fact that the unit still worked fine in the cooling mode, it just wouldn't switch to the heat mode.



I finally went up on the roof with my trusty muiltmeter and did a little diagnosis. It turned out there was no signal to the operating solenoid regardless of the settings at the thermostat. At that point I suspected the control module under the AC shroud.



I called the Airxcel technical hotline and explained the situation to one of their technicians. He agreed with my diagnosis and sent me a new control module at no charge. I installed the module and everything has worked fine since.



The control modules are available directly from Airxcel or from a dealer at a cost of about $250.00. In our case it was provided free of charge since it had been an intermittent problem while the coach was still under warranty.

Interesting and I agree. The $1,600 price was a rip. They are $800 to $900 at several online vendors and only an hour of installation time.

[chuckinthebus]

Go further south?

[oatmeal]

Originally Posted by wildtoad

Mine ( Dometic ) will auto switch to furnace if the outside temp is too cold for the hp to work properly. It is a “feature” of the system so make sure to have propane available.

How does that explain why one unit was switching to propane but the other wasn't?

[FixerCQI]

I think if you have 2 furnaces each controls one of them, the one in the same room of course.

[FixerCQI]

Each heat pump has it's own thermostat in the above scenario.

[cimplexsound]

Heat pumps don't run on LP. They are electric. They are usually 110 V AC

[shiggs68]

Originally Posted by cimplexsound

Heat pumps don't run on LP. They are electric. They are usually 110 V AC

The Coleman thermostat I posted a picture of above switches to the LP RV furnace when the setpoint and current room temperature difference are greater than 4 degrees or the outside temperature is below the heat pump’s efficiency. You missed the point of the posting.

[Hikerdogs]

Originally Posted by oatmeal

How does that explain why one unit was switching to propane but the other wasn't?

I all depends on how low the system can transfer heat without freezing over. Some units will continue to function down to 35* while others will freeze over at 38* - 40*. As long as the coil mounted sensor doesn't detect the coils freezing over the unit will still provide some heat.

[FixerCQI]

Originally Posted by cimplexsound

Heat pumps don't run on LP. They are electric. They are usually 110 V AC

The "heat pump" is part of the hvac system as is the furnace. The furnace runs on LPG.
I think we are having trouble explaining the problem because we all have different systems. Apples and Colemans so to speak.

[Yellowboat]

One reason why RV's switch to propane when cold is because, as stated above, heat pumps are not very efficient below 40 Degrees F. By switching to propane the heating system will keep the pipes from freezing when in minus 32 degrees F. conditions. Without this feature more RV's would have broken water pipes.

My propane heater wasn't working correctly. My dealer replaced a circuit board and limit switch. Prior to the repair the heater would cycle once and then it would allow the temperature to drop. I was worried that my wet bay could freeze without heat.

All is fine now with the heater plus I'm winterized.

Safe travels. JD