Heat Pump

[Loony79]

Could someone help with the temp the heat pump will operate down to? Will the system automatically switch to the propane furnace if temp goes too low? Thanks in advance.

[Dtwallace]

Originally Posted by Loony79

Could someone help with the temp the heat pump will operate down to? Will the system automatically switch to the propane furnace if temp goes too low? Thanks in advance.

No it will not, unless there is a new type out there I'm not familiar with.

In my experience with using mine in low temperature weather conditions, it won't work if the outside temperature drops too far below 45F.

Mine will ice up once it detects any ice build up.

RV heat pumps don't deice like home units, and once it stops producing heat inside, you have to manually change over the LPG.

As an example, my coach bed room is heat pump only, the other two zones are LPG.

When it gets too cold outside for the heat pump to work, I'm rudely awaken by a frigid cold breeze from it until I can turn it off. Then it's a matter of adding a portable heater to bring the room back up to a comfortable temperature.

Nature of the beast

DTW

[Loony79]

Thank you! Day #1 with the new MH. Lot to learn............

[Mr_D]

Originally Posted by Loony79

Could someone help with the temp the heat pump will operate down to? Will the system automatically switch to the propane furnace if temp goes too low? Thanks in advance.

Yes, some will, our '00 and '02 DSDP's would automatically switch over. They also had heating coils to unthaw the coils when they iced up, they weren't for providing heat though, just to unthaw the coils.
They worked pretty well till down to about 35°, then the furnace would kick in and the heat pumps would shut off.

[Old Crows]

They work to about 40 - 35F... Depends on the unit and it's age. Can't say for sure because we don't know your model heat pump. Our Coleman Mach 8 will auto switch to LP furnace when it can't maintain the set point.

It uses a complicated algorithm to "test" it's ability to maintain the set point. If it can't, it will continue to try until it can while using the LP furnace for heat.

And, a Mach 8 automatically will go to defrost cycle when needed, just like the one in your house. It will use the LP furnace for heat in the mean time.

What a lot of folks do because the HP & furnace are noisy is to use a small ceramic cube electric heater if you have shore power. They are quiet and give a uniform heat in the coach.

[mrfix]

Mine will be effective to 45 degrees, once the temp in the coach goes 3 degrees below the thermostat set point it will start the propane furnace and lock out the heat pump for 3 hours the try again. The way I run the coach is if the forecast is to go below 45 during the night I just switch to propane before I go to bed for efficiency purposes.

[Dtwallace]

Originally Posted by Mr_D

Yes, some will, our '00 and '02 DSDP's would automatically switch over. They also had heating coils to unthaw the coils when they iced up, they weren't for providing heat though, just to unthaw the coils.
They worked pretty well till down to about 35°, then the furnace would kick in and the heat pumps would shut off.

Hey MR D,

Can you provide the model of that heat pump you mentioned? Like to see if there is a modification that can be added to deice the coils.

Thanks

DTW

[Isaac-1]

Operating temperature depends on the brand, model and exact conditions. With the dometic / dual therm (at least the models I am aware of) the 13,500 btu heat pumps work down to about 37 degrees (sensed at the coil) which then trips a thermal cut off switch, the 15,000 btu units have a special defrost reverse cycle mode where they cycle the reversing valve without running the fan to defrost the coil, then go back to heating mode every few minutes when temperatures are low, which allows operation down to 29 degrees, but at much reduced efficiency.