Dometic thermostat won’t cycle furnace off

Dan54

Well-known member
We just pulled our 2011 Landmark out of storage for a trip south. During the winter we had to have our Dometic heat pump replaced. When we were prepping the trailer for the trip we discovered the thermostat didn’t offer Furnace as an option, only
Off, Auto, Cool & Heat Pump. The installing mechanic called Dometic & they said the #8 dip switch had to moved to the on position. That did solve the problem but now as we sit here this morning in Gulf Shores, Alabama we are definitely suffering from too much “Furnace”. The thermostat didn’t shut the furnace off all night long despite having the temperature set at 67 degrees. The temperature is way over 67 but reads only 63 (outside temp is 41). Could the calibration have been thrown off when the heat pump was replaced? If so can it be recalibrated? Thanks.


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Hollandt

Well-known member
We just pulled our 2011 Landmark out of storage for a trip south. During the winter we had to have our Dometic heat pump replaced. When we were prepping the trailer for the trip we discovered the thermostat didn’t offer Furnace as an option, only
Off, Auto, Cool & Heat Pump. The installing mechanic called Dometic & they said the #8 dip switch had to moved to the on position. That did solve the problem but now as we sit here this morning in Gulf Shores, Alabama we are definitely suffering from too much “Furnace”. The thermostat didn’t shut the furnace off all night long despite having the temperature set at 67 degrees. The temperature is way over 67 but reads only 63 (outside temp is 41). Could the calibration have been thrown off when the heat pump was replaced? If so can it be recalibrated? Thanks.


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Is the thermostat installed on an outside wall or on a wall that is somehow seeing cooler temps then the actual air temp inside? If the actual temp on the stat is showing 63 then that is what it is controlling around.
 

Dan54

Well-known member
Inside wall almost directly in the middle of the trailer. Accuracy hasn’t been an issue since we bought it in 2017 until now. The only thing that’s changed is we had the heat pump replaced in January. The fact that the installer didn’t know to check the dipswitch settings makes me wonder what else they screwed up.


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Dahillbilly

Well-known member
We just pulled our 2011 Landmark out of storage for a trip south. During the winter we had to have our Dometic heat pump replaced. When we were prepping the trailer for the trip we discovered the thermostat didn’t offer Furnace as an option, only
Off, Auto, Cool & Heat Pump. The installing mechanic called Dometic & they said the #8 dip switch had to moved to the on position. That did solve the problem but now as we sit here this morning in Gulf Shores, Alabama we are definitely suffering from too much “Furnace”. The thermostat didn’t shut the furnace off all night long despite having the temperature set at 67 degrees. The temperature is way over 67 but reads only 63 (outside temp is 41). Could the calibration have been thrown off when the heat pump was replaced? If so can it be recalibrated? Thanks.


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I'd call Dometic & ask them about those DIP settings
 

Dan54

Well-known member
Update since traveling to New Orleans with 85 degrees & high humidity. Just like with furnace operation the thermostat is not calibrated properly when in cooling mode. Because it was so far off I bought a wireless in/out digital thermometer to compare readings. At about 4pm outside temp was reading 83 on the Dometic thermostat & 84 on the thermometer. The target temp was set to 63 because when set for 72-74 the actual temp didn’t get close & I had noticed during furnace operation the target & actual were 6-8 degrees off. I decided to measure the time it took to cycle off/on/off because it seemed to be happening too frequently. The time from off to on averaged two minutes as did the time on to off. The temp when cycled off was 69 & the temp when turned on was 73. Doesn’t seem right in 2 minutes but that’s what it said thru 8 on/off cycles. The thermometer by comparison showed 79-81, 81-81, 80-80, 80-80 in 4 cycles. Makes me think it also is not accurate. Any thoughts, suggestions are welcome. Thanks!


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