Heat pump/Furnace co-working issue.

[FIRE UP]

Gents,
It states in the owners manual of our '04 Itasca Horizon 36GD with the 330 CAT that, when the ambient temp, inside the coach is at least FOUR degrees lower than the SET temp of the thermostat, that BOTH the furnace and the heat pump system will come on simultaneously to bring the temp up in the coach at a faster rate until the desired temp is reached. From that point on, the heat pump will operate only, keeping the desired temp up to snuff.

I know and realize that the heat pump is a less effecient way of heating the coach and, we use it on occasion. The furnace does a real good job of bringing up the temp when used. But, to my recollection, I've only experienced the both of them coming on ONE time. So, without any investigation into this issue, I'm assuming the fix would most likely be a new thermostat since, that's what controls all of the heating and A/C and, which unit is supplying that heat. Thanks in advance.
Scott

[smlranger]

Scott, the RVP T stat can 'lose it's mind' on occasion. I've had to remove it, unplug the phone-type connector and reconnect it and, presto, it will behave. So, you might try that.

Also, suggest you set the desired temp 5 or more degrees higher than the actual temp and see if that makes the furnace come on with the heat pump.

I'm on my second T Stat and whenever I set the temp 5 degrees above ambient, both heat pump and LP furnace kick on.

We've been surprised and pleased at how well the heat pump provides heat. Our's does a good job down to about 34 F outside temp, depending on humidity. I don't believe our heat pumps have a defrost cycle so they can freeze up if it is both cold outside and humid.

[mikf]

Scott, I would not change t-stat until you investigate it more. I am not sure right now what the perameters are, but on ours if the the heat pump cannot keep up the propane kicks on and locks the heat pump for an hour and then then every hour the heat pump will try again. I am pretty sure the hour time is right. it has to get pretty cold for that to happen.

[FIRE UP]

Gents,
I certainly thankyou for taking the time to respond here. I'm always up for trying an "easy" fix first. And, if that means disconnecting the t-stat and phone wire(s), I'm on it. Now, to figure out how the t-stat comes off the panel. I'll take a good look at it tomorrow. It's late, my eyes are straining to stay open, so, I attack at dawn, well, maybe a bit later. Thanks again.
Scott

[Mr_D]

Originally Posted by FIRE UP

I know and realize that the heat pump is a less effecient way of heating the coach and, we use it on occasion.

A heat pump is a VERY efficient way to heat. They are much more efficient than just an electric furnace or heater. The heat doesn't feel as warm due to the air temp exiting them is lower than a furnace.
Here in the NW with our moderate winters the heat pump is almost as cheap to run as a natural gas furnace, although natural gas has gone down some lately.

[FIRE UP]

Originally Posted by Mr_D

A heat pump is a VERY efficient way to heat. They are much more efficient than just an electric furnace or heater. The heat doesn't feel as warm due to the air temp exiting them is lower than a furnace.
Here in the NW with our moderate winters the heat pump is almost as cheap to run as a natural gas furnace, although natural gas has gone down some lately.

Mr_D,
My statement about them being "inefficient" is due to my limited knowledge of how they actually work. I've read that they "extract" heat from the outside air and, through a sort of "transfer" of that heat,move it to the inside of the coach (or house). But, the colder it is outside, the less effecient that system is. That's what I've read anyway. I, by far am certainly no expert in this matter. Thanks for correcting me here.
Scott

[smlranger]

Scott, if your T-Stat is the standard black plastic model that I've seen in most Winnebago's, the front snaps off revealing two screws that hold the base (with all the brains) to the wall. Remove the screws and you are good to go.

[FIRE UP]

Originally Posted by smlranger

Scott, if your T-Stat is the standard black plastic model that I've seen in most Winnebago's, the front snaps off revealing two screws that hold the base (with all the brains) to the wall. Remove the screws and you are good to go.

smlranger,
Thanks for the instructions. Mine however is white, not black. I suspect (due to seeing every other one in multiple Itasca and Winne coaches) that it's been changed at one time or another. The previous owner mentioned nothing about and change. It looks just like the black ones, same shape, dimentions, readings, dials, buttons, slide switches, etc but, it's white. I'll look closer this morning. Thanks again.
Scott

[Sammie]

Originally Posted by FIRE UP

Gents,
It states in the owners manual of our '04 Itasca Horizon 36GD with the 330 CAT that, when the ambient temp, inside the coach is at least FOUR degrees lower than the SET temp of the thermostat, that BOTH the furnace and the heat pump system will come on simultaneously to bring the temp up in the coach at a faster rate until the desired temp is reached. From that point on, the heat pump will operate only, keeping the desired temp up to snuff.

I know and realize that the heat pump is a less effecient way of heating the coach and, we use it on occasion. The furnace does a real good job of bringing up the temp when used. But, to my recollection, I've only experienced the both of them coming on ONE time. So, without any investigation into this issue, I'm assuming the fix would most likely be a new thermostat since, that's what controls all of the heating and A/C and, which unit is supplying that heat. Thanks in advance.
Scott

Scott, It's been my experience that the switch you move to go from Off to Gas and then to Electric has contacts on the inside that may become dirty. If you move the switch back and forth several times, you can clean up the contacts enough so that the thermostat will start to function as it should. I found this out after I bought a new thermostat ( which I now carry for a spare ) along with other spare parts.

Sammie

[FIRE UP]

Ok Gang,
Here's the latest on the issue. I removed that thermostat. Then, I moved all the switches back and forth, about a zillion times to try and clean off the contacts. I then replaced it back onto the One Place Panel. The ambient temp was 70 inside the coach, according to the T-stat. So, I set the required temp to about 80. I figured it would satisfy the requirements of the "5 degree" over the ambient temp. Then, I moved the switch to "Electric" heat.

Well, the gas furnace came on but, no heat pump. I waited for a bit. No heat pump. I turned the whole thing off. I tried it again. No heat pump. So, I came into the house and did some more reading on it. Well, just for grins, I went back out and this time, I put the required temp at only "2" degrees above the ambient temp. Whamo, the heat pump came on without the furnace. Hmmmmmm. To my knowledge, that's how it's supposed to work unless the set temp asks a 5 degree or more rise.

So, at this time, while the heat pump works, it's not working the "Co-operation" with the furnace that it's supposed to, based on how you set the desired temp. Not sure what to do now. I have no idea what thermostat costs but, it might be an expensive experiment, any ideas?
Scott

[ScottLee]

I had the same exact situation and have learned the same things as you have Scott. I replaced my tstat for $120.00. It didn't solve the problem of the "co-operation" either. When the outside temps drop below 32, the tstat calls for gas furnace but it will come on (low fan) and then about 15 seconds later, it shuts off.

I'm being told that I either have moisture in the LP tank and it is causing the regulator to freeze up or I have a bad "sail switch".

I'm stuck as well.

[Duner]

I've repaired my black Coleman Mach a few times before I replaced it with a digital set-back t-stat.

The Coleman t-stat has a basic design defect in the way they use two 4-position slide switches ganged together. The top switch gets torqued sideways and loosens up the metal bracket. So then the top switch is left in between normal position and doesn't give the correct connection. My best guess is that one switch controls the elec heat pump while the other controls the gas furnace. Then they get out of sync so the gas doesn't come on when you expect it. Or you can get other symptoms too....like mine would not kick on the heat pump unless we wiggled the switch back and forth.

I was able to get mine working again by tightening up the metal switch brackets by bending little tabs at the bottom corners of each switch. In time it would fail again.

I think you can prove my point by setting your switch to the Elec Heat position, then pop off the t-stat cover, then push both switches to the far right so that they are firmly in the last position. Both heat sources should then be operational.

Good luck with yours,
Bill

[FIRE UP]

Originally Posted by Duner

I've repaired my black Coleman Mach a few times before I replaced it with a digital set-back t-stat.

The Coleman t-stat has a basic design defect in the way they use two 4-position slide switches ganged together. The top switch gets torqued sideways and loosens up the metal bracket. So then the top switch is left in between normal position and doesn't give the correct connection. My best guess is that one switch controls the elec heat pump while the other controls the gas furnace. Then they get out of sync so the gas doesn't come on when you expect it. Or you can get other symptoms too....like mine would not kick on the heat pump unless we wiggled the switch back and forth.

I was able to get mine working again by tightening up the metal switch brackets by bending little tabs at the bottom corners of each switch. In time it would fail again.

I think you can prove my point by setting your switch to the Elec Heat position, then pop off the t-stat cover, then push both switches to the far right so that they are firmly in the last position. Both heat sources should then be operational.

Good luck with yours,
Bill

Bill,
I surely want to thank you and others for trying to assist me in this issue. As stated, both systems work, just not at the same time, as they're supposed to during certain circumstances. I also removed the T-stat and moved the switches back and forth several times to try and make good, clean contacts. They felt solid as they slid back and forth. Now, for a technical question.

We're presently hooked up to shore power at our home. It's a 15 amp circuit. And, Iv'e got a 50', 12GA extension cord plugged into the wall outlet in the patio which, is coupled to a 25', 12GA extension cord which, is coupled to the 50A-30A adapter via a 15A adapter. How about that for a plug in?

So, my question is, if the "Powerline" energy management system detects that there's not enough available power to supply the heat pump's demand in juice, maybe it's not going to let the heat pump even try and start, hmmmmmm. But, I've also tried this operation on the generator only. And, it still didn't work. So, I'll go out and try your method Bill and see how it works. Thanks again.
Scott

[Sammie]

Scott, I went out and tried my Heat Pump / Furnace this morning for fun. The ambient temp was 60 and I set the thermostat to 68. Both the heat pump and gas furnace came on and stayed on until it reached 68 degrees. I do have a 30 amp power supply that the coach is directly plugged into.
The price for a new thermostat from Lichtsinn Motors is $185.00 including shipping. That includes a new style pigtail that you will need to go from the old wiring to the newer thermostat.

Sammie

[luckydog1949]

The thermostat in our '05 Horizon 36RD has separate switch positions for "cool", "off", "gas heat", and "elec heat." The manual says that if the selector is set on "elec heat", the heat pump will run; but, if the outside temp is too low the heat pump will shut down and the gas heat will kick in. It's not working that way, at all! When set on "elec heat", the heat pump comes on, no matter what the exterior temp is; and, it will not change over to gas when the heat pump fails to keep up. The heat pump "radiator" ices up, too. It also takes a while, sometimes, to get the A/C to come on when "cool" is selected. Wondering if I have a thermostat problem, or if there is a problem with some control board.

[moejean]

We are having the same problem on our 2011 Sightseer. When I exercised the generator last December and used the HP as a load on the generator all was well. Then in January and February while doing the same exercise the HP would very briefly start then switch to furnace. The outside temp was about 40 degree F and the inside temp was about 3 degree separation. The rear HP, which is just Air and HP, worked fine so it wasn't too cold outside. I am going to wait until our first trip this May before I take it to the dealer for repair. This will allow me to document the exact symptoms since we will be in the MH for a six week period.
Moe

[DancinCampers]

Luckydog, I would suspect tstat. The following is from my previous coach, 03 Adventurer:

6535-3351 Heat Pump Thermostat Example To Bring On Gas Furnace as 2nd Stage Heat
Setpoint = 70 deg
Indoor Temp. Operation
70+ No functions occur
69 Heat Pump turns on (Primary heat source)
71 Heat Pump turns off (Thermostat satisfied)
69 Heat Pump turns on
65 Gas Furnace turns on (Heat Pump not able to satisfy Thermostat)
(First strike for 2nd stage heat counter)
71 Heat Pump and Gas Furnace turn off (Thermostat satisfied)
69 Heat Pump turns on
65 Gas Furnace turns on (Heat Pump is again unable to satisfy
Thermostat), (2nd stage heat counter reaches 3rd strike and Heat Pump is
locked out for 2 hours), 2nd stage heat counter is reset if Heat Pump is
running for more than 20 minutes and does not call for 2nd stage heat
71 Gas Furnace turn off (Thermostat satisfied)
69 Gas Furnace turns on (Becomes Primary heat source)
71 Gas Furnace turns off (Thermostat Satisfied)
\\\ After 2 hour lockout
69 Heat Pump turns on (Resumes as Primary heat source)
65 Gas Furnace turns on (Becomes primary heat source)
(Heat Pump is locked out for another 2 hours)
71 Gas Furnace turns off (Thermostat Satisfied)
\\\ After 2 hour lockout
69 Heat Pump turns on (Resumes as primary heat source)
71 Heat Pump turns off (Thermostat satisfied)
(2nd stage heat counter is reset any time Heat Pump satisfies
thermostat setpoint and does not need Gas Furnace)

You might try resetting the tstat by disconnecting house batteries for a few minutes or pulling internal tsat fuse.

Outside icing is normal during operation in colder temps/higher humidity. The outdoor coil thermister measures coil temp, and should shut off basement unit before too much ice accumulates. If this happens, the tstat goes into a default mode, and the gas furnace will operate between 45 and 60 deg. Gas heat should be selected at this point.

[luckydog1949]

Originally Posted by DancinCampers

Luckydog, I would suspect tstat. The following is from my previous coach, 03 Adventurer:

6535-3351 Heat Pump Thermostat Example To Bring On Gas Furnace as 2nd Stage Heat
Setpoint = 70 deg
Indoor Temp. Operation
70+ No functions occur
69 Heat Pump turns on (Primary heat source)
71 Heat Pump turns off (Thermostat satisfied)
69 Heat Pump turns on
65 Gas Furnace turns on (Heat Pump not able to satisfy Thermostat)
(First strike for 2nd stage heat counter)
71 Heat Pump and Gas Furnace turn off (Thermostat satisfied)
69 Heat Pump turns on
65 Gas Furnace turns on (Heat Pump is again unable to satisfy
Thermostat), (2nd stage heat counter reaches 3rd strike and Heat Pump is
locked out for 2 hours), 2nd stage heat counter is reset if Heat Pump is
running for more than 20 minutes and does not call for 2nd stage heat
71 Gas Furnace turn off (Thermostat satisfied)
69 Gas Furnace turns on (Becomes Primary heat source)
71 Gas Furnace turns off (Thermostat Satisfied)
\\\ After 2 hour lockout
69 Heat Pump turns on (Resumes as Primary heat source)
65 Gas Furnace turns on (Becomes primary heat source)
(Heat Pump is locked out for another 2 hours)
71 Gas Furnace turns off (Thermostat Satisfied)
\\\ After 2 hour lockout
69 Heat Pump turns on (Resumes as primary heat source)
71 Heat Pump turns off (Thermostat satisfied)
(2nd stage heat counter is reset any time Heat Pump satisfies
thermostat setpoint and does not need Gas Furnace)

You might try resetting the tstat by disconnecting house batteries for a few minutes or pulling internal tsat fuse.

Outside icing is normal during operation in colder temps/higher humidity. The outdoor coil thermister measures coil temp, and should shut off basement unit before too much ice accumulates. If this happens, the tstat goes into a default mode, and the gas furnace will operate between 45 and 60 deg. Gas heat should be selected at this point.

DancinCampers, thank you for the detailed information! The outside icing on ours was pretty heavy. I'll check to see where the thermister is mounted, to be sure it's taking a valid reading. And, I'll reset the thermostat and retry the process using the temp differences you mentioned. I was leaning toward the thermostat, too; but, had no way to confirm it. I believe I do, now.

Tom