Is there a problem with heat pump? - RV-Dreams Community Forum

cherylbrv · RV-Dreams Family Member

Is there a problem with heat pump?

PIEERE · RV-Dreams Family Member

First make sure you have the tank valve open and if dual tanks that the right one is open. Neexr, There is a switch called a 'sail switch', it is in the furnace. It sometimes gets debris, dust, etc. In it and won't make a contact to allow the propane to flow.

TRAILERKING · RV-Dreams Family Member

I don't think a heat pump runs on propane.....

BiggarView · RV-Dreams Family Member

Heat pumps become less efficient as the temperature drops. You might want to switch to your furnace or other heat source.

travlingman · RV-Dreams Family Member

Most heat pumps I have saw on 5th wheels usually only work to upper 30's and then you have to use furnace. Are you sure you have heat pumps and not heat strips?

bjoyce · RV-Dreams Family Member

Different model heat pumps do behave differently. I know with Dometic the 13.5K BTU units work down to around 38 to 40 degrees and then either turn on the furnace (if on the same thermostat) or blow cold air. The 15K BTU Dometic units go into de-ice mode around 38 degrees, where they close up and warm up their coils (internals) for 4 minutes every 20 to 30 minutes. This allows them to run down to around 30 degrees and even into the mid-20s in dry air (Arizona). We have two 15K Dometic heat pumps and when the front one can no longer heat, it turns on the furnace since the furnace is on the same thermostat. On 30AMP we can only run one of the heat pumps, so we have to manually switch to furnace in the low 40s.

PIEERE · RV-Dreams Family Member

TRAILERKING wrote:
I don't think a heat pump runs on propane.....

disbelief This is what happen s when one like me has Drain Bramages!!! biggrin biggrin

cherylbrv · RV-Dreams Family Member

Ed - it is the electric, not propane.

Brian - I never realized that heat pumps weren't efficient! The solution for me is to GET OUT OF THIS COLD AREA!!! (which we're doing right after Thanksgiving).

Bill - I'm not sure if we have the 13.5K or 15K BTU but I know that the a/c, heat pump and furnace are all on the same thermostat. I think it might be doing what you mentioned above (de-ice mode) or else it's just not cycling on when it's below freezing (it's been as low as 25).

How do I know if it automatically switches to furnace? I guess the obvious answer is that the room would be warm!

Right now, I'm finding that using the fireplace keeps it nice and toasty.

Dave Buck · RV-Dreams Family Member

Cheryl, we have basically the same unit as you do. As was mentioned above the heat pump doesn't work much below 40 and if so is very inefficient. We typically only use the heat pump when the temps are in the upper 40's and 50's. We use an electric heater in combination with the fireplace most of the time. Only use the furnace when the temperature is going to be down in the mid 20's for a length of time.

bjoyce · RV-Dreams Family Member

Above about 40 degrees a heat pump will put out around 11,000 BTUs of heat and a normal space heater only puts out about 5,000 BTUs using the same electricity. But as it gets colder outside, the heat pump can't extract the heat as well and the efficiency goes down. Just like an air conditioner has more trouble over 95 degrees, for the same reason, since a heat pump is a reversing air conditioner.

A fireplace or space heater heats from the ground up, which is better than blowing down from the ceiling. Hot air rises. In cold weather we run a propane heater in the living room and an electric space heater in the bedroom, on hookups. In milder weather we run the heat pumps.

Sorry, I only know what the 5-button Dometic thermostats do. Our thermostat tells us when the heat pump is in de-ice, there is a small message on the display. It also tells us "aux heat" when it runs the propane furnace.

Florida is mostly above freezing, so you will be happier here. St. Augustine is supposed to have a low of 36 tonight, since you were talking about going there. Here in Fort Pierce, which is further south, the low is supposed to be 50. We just left Big Pine Key, where the low tonight is supposed to be 63. We will miss the warmer weather, but two weeks in the Keys was plenty for us. The Keys are great, but we get island fever, miss the variety of stores outside the Keys, everything costs a bit more and the camping is much more expensive.

The Junkman · RV-Dreams Family Member

I guess we will put mine to the test...

I have 2 heat pumps going .. and the electric fireplace set to about 70..

Heatpumps and the fireplace are coming on and off..

43 degrees outside right now.. and 73 degrees inside..

Are you sure you have a heat pump on the living area ac? I ordered mine with only 2 .. and I have 3 ac's... the spare room one, does not have a heat pump..( rear )

cherylbrv · RV-Dreams Family Member

Dave Buck wrote:
We typically only use the heat pump when the temps are in the upper 40's and 50's. We use an electric heater in combination with the fireplace most of the time.

That's air conditioning weather!!! biggrin

PIEERE · RV-Dreams Family Member

cherylbrv wrote:
Ed - it is the electric, not propane. What I was insinuating!!! Dain bramage! Mine!!!!!

Brian - I never realized that heat pumps weren't efficient! The solution for me is to GET OUT OF THIS COLD AREA!!! (which we're doing right after Thanksgiving).

Bill - I'm not sure if we have the 13.5K or 15K BTU but I know that the a/c, heat pump and furnace are all on the same thermostat. I think it might be doing what you mentioned above (de-ice mode) or else it's just not cycling on when it's below freezing (it's been as low as 25).

How do I know if it automatically switches to furnace? I guess the obvious answer is that the room would be warm!

Right now, I'm finding that using the fireplace keeps it nice and toasty.

-- Edited by PIEERE on Tuesday 18th of November 2014 07:30:32 PM

Terry and Jo · RV-Dreams Family Member

I guess I need to dig out the manual on our AC/Heat pump units. In our case, I tend to watch the weather with regards to temperatures and switch to the furnaces (we have the Canadian Package, thus two 30,000 btu furnaces) when the forecast indicates pretty cold weather. I've not had ours automatically switch to furnace from heat pumps.

Terry

The Junkman · RV-Dreams Family Member

Went to 33 last night.. I shut off the heat pumps before going to bed.. noisey.. just ran the fireplace and the ceiling fan.. woke 63 in the camper.. and I slept with a fan on me...always..

Was nice..

Any colder and the heat pumps will need to come on or the furnace. I think

did you figure out the heat pump issue?

-- Edited by The Junkman on Wednesday 19th of November 2014 06:49:21 AM

-- Edited by The Junkman on Wednesday 19th of November 2014 06:50:21 AM

cherylbrv · RV-Dreams Family Member

It did appear that the heat pump switched over to furnace during the night, as the sound was much different. Unfortunately, it used up the remainder of the propane, so no heat until we got up and switched to the other tank. Also awoke to a frozen water hose so no water until that melts. It should get as high as 40 later today :(

Bill and Linda · RV-Dreams Family Member

Bill J’s comments are correct as usual. To add a bit, different thermostats do this differently – but in general:

Heat pumps are not very efficient / will work below about 40 degrees.

Most systems (thermostats) will turn on the furnaces – LP/Gas – in addition to running the heat pump when:

The requested temperature on the thermostat (set point) is above 3 to 5 degrees above the room’s temperature (as determined by the manufacturer – not user set-able) the furnace will run
Sometimes the first time heat is requested i.e. when you first turn on the heat pump and want it go into the heating mode, some systems also turn on the furnace for the first warm up. After than it will not run again unless the heat pump can’t keep up with the temperature set point (next point 3)
When the temperature requested (set point) is not reached within a given time frame (as determined by the manufacturer – not user set-able) the furnace will turn on and run the furnace fan LP Gas or not - I.e. even with empty tanks.

Read the manual for your particular system. If you don’t have one they are usually available on-line with just a little hunting.

The following is a personal preference, but I keep both LP tanks open so if one runs out the other one will take over. Yes, the auto regulator will do the switch over and almost all RV’s have this. It will also show you when a tank is empty; little red / flag thing on the regulator – turns from green to red or blank to red on the older ones when a tank runs out.

Some feel if you do this you could empty both tanks without knowing it. Well, IMO, keeping tabs on your LP is like emptying the holding tanks. It’s just something you do and if so you won’t end up cold in the middle of the night.

All of the above is very common and has been for a long time. We just have to learn how these things work in our particular rig.

Keep in mind all of this is dependent on the brand, type and age of the thermostat installed to run the system. Not what brand of rig or AC / heat pump you have. Different years of trailers, even in the same year, can have different types of thermostats and they will have slightly different set points which trigger furnace operation when the heat pump is enabled.

Finally, the defrost cycle on the heat pump is not controlled by the thermostat - that is totally controlled by ice sensors in the heat pump itself. Ice on the coils heat exchanger coils - not ice outside of the rig.

FWW should this be helpful in general

The Junkman · RV-Dreams Family Member

Ours has HP .. assuming HP only..
and AUTO.. I assume for furnace
And COOL for ac
and FAN .. for fan..

I hope the HP - heat pump does NOT auto switch over to auto - furnace.. as I have covers on the vents, and maybe start a fire.. I better check that.

Bill and Linda · RV-Dreams Family Member

The Junkman wrote:
Ours has HP .. assuming HP only..
and AUTO.. I assume for furnace
And COOL for ac
and FAN .. for fan..

I hope the HP - heat pump does NOT auto switch over to auto - furnace.. as I have covers on the vents, and maybe start a fire.. I better check that.

Steve, I would assume it does - That is the furnace WILL come on if certain temperature / time conditions occur and you have it in any "heat on" mode. Been there - seen it work that way - for a long time and I've read the manuals. I know with some systems you can "lockout" heat pump operation. But I've not had a system where, if you select a heating mode "on" condition that it will NOT turn on the furnace IF it needs more hot air to make the set temperature and the thermostat is integrated and controls both the AC/heat pump AND the furnace with one thermostat control.

Actually your question was one of the reasons for my post. RV heating systems, many of them, are actually controlled, 12 volt power wise, by way of the furnace. These systems are similar, but different from the operation of home HVAC systems. Best we all learn how they work as they do work differently. "Assume nothing" is not a bad idea.

(More data: If a trailer has more than one AC/heat pump unit but only ONE furnace - then usually only the living area heat pump will be integrated with the furnace for supplemental heating control. If there are two finances than each furnace will be controlled individually by each heat pump. "It depends." )

On edit: The "Auto" part is for fan operation. Auto means the fan (most of the time) will only run when the AC / heat pump is "on." In the FAN-ON position the fan will always run. This is normally just a fan "Auto" thing. (This does work like a home "Auto Fan" switch.)

Steve: Looking at the pictures you sent you do have one of the new systems where there is a second "Auto" mode which allows the system to decide to run heat or air conditioning as needed "automatically."

-- Edited by Bill and Linda on Wednesday 19th of November 2014 03:17:25 PM

-- Edited by Bill and Linda on Thursday 20th of November 2014 08:18:15 AM

SnowGypsy · RV-Dreams Family Member

For those that received the manuals with their RVs, there should be separate booklets for all the systems that will tell you what you have and what you might do with it.

Cheryl: We were in the same area as you are 15 years ago through 2 winters. I do suggest getting a 2nd fresh water hose because once it freezes, it takes more than getting above freezing to thaw it out, think ice cubes in a container. It is also nice to have a 2nd one when one springs a leak. The fresh water can be frozen right at the inlet, ice chunk. The action that my hair dryer got those 2 years more than justified the space it took up!

The Junkman · RV-Dreams Family Member

Bill and Linda wrote:
The Junkman wrote:
Ours has HP .. assuming HP only..
and AUTO.. I assume for furnace
And COOL for ac
and FAN .. for fan..

I hope the HP - heat pump does NOT auto switch over to auto - furnace.. as I have covers on the vents, and maybe start a fire.. I better check that.
Steve, I would assume it does - That is the furnace WILL come on if certain temperature / time conditions occur and you have it in any "heat on" mode. Been there - seen it work that way - for a long time and I've read the manuals. I know with some systems you can "lockout" heat pump operation. But I've not had a system where, if you select a heating mode "on" condition that it will NOT turn on the furnace IF it needs more hot air to make the set temperature and the thermostat is integrated and controls both the AC/heat pump AND the furnace with one thermostat control.
Actually your question was one of the reasons for my post. RV heating systems, many of them, are actually controlled, 12 volt power wise, by way of the furnace. These systems are similar, but different from the operation of home HVAC systems. Best we all learn how they work as they do work differently. "Assume nothing" is not a bad idea.
(More data: If a trailer has more than one AC/heat pump unit but only ONE furnace - then usually only the living area heat pump will be integrated with the furnace for supplemental heating control. If there are two finances than each furnace will be controlled individually by each heat pump. "It depends." )
On edit: The "Auto" part is for fan operation. Auto means the fan (most of the time) will only run when the AC / heat pump is "on." In the FAN-ON position the fan will always run. This is normally just a fan "Auto" thing. Nothing to do with anything else in most cases. (This does work like a home "Auto Fan" switch.)

-- Edited by Bill and Linda on Wednesday 19th of November 2014 03:17:25 PM

I'm not sure .. will read the book tommarrow..

I don't have "heat mode"

I think auto is the furnace .. not fan.. I have a fan mode w/ auto..

Here's what it looks like.. I assume all are the same, maybe they changed ?

No worries..I'll get to it.. so far , we shut down the hp's at night.. too noisy.. and just have the fireplace running.. was like 33 outside this am.. 65 or so inside.. it's amazing the heat you get out of these things..

Barbaraok · RV-Dreams Family Member

One of the things to watch when the temp dips towards the freezing point is that you are getting heat to your tanks or in some way keeping your tanks warm. Often this is accomplished with a duct from the furnace into the area with the tanks. While the space heaters will keep you warm, they won't warm the tanks.

Barb

The Junkman · RV-Dreams Family Member

Yea.. time to start using the furnace I think.. Down to 30 this morning outside. Fireplace has seen it's limit.. 58 in the trailer this morning..

Turned the heat pumps on .. and it swapped over flashing FURN then HP.. Furnace came on.. I ran and took the covers off.. I think I got them all..lol

Bill and Linda · RV-Dreams Family Member

The Junkman wrote:
Yea.. time to start using the furnace I think.. Down to 30 this morning outside. Fireplace has seen it's limit.. 58 in the trailer this morning..

Turned the heat pumps on .. and it swapped over flashing FURN then HP.. Furnace came on.. I ran and took the covers off.. I think I got them all..lol

Steve: Looking at the pictures you sent you do have one of the new systems where there is a second "Auto" mode which allows the system to decide to run heat or air conditioning as needed "automatically."

Glenn West · RV-Dreams Family Member

Steve, on ours, if it is 68 in unit and we turn on fireplace it will maintain 68ish down to upper 20s we know. haven't seen anything lower with this unit. Now if it is 50 in unit fireplace will not heat it up to 68 by itself. Just doesn't have the btu to bring up temps but enough to maintain. Our DRV and our Teton heatpumps will change over automatically to furnace when needed. And that seems to vary with use of fireplace also.

The Junkman · RV-Dreams Family Member

cool.. thanks folks.. gonna run in a"auto" tonight.. just got home..

Will run the fireplace til we go to bed..