Community Forums

dirt40 · 02-29-2020, 04:55 PM

Hey guys, my thermostat for some reason brings on my gas furnace when I have it switched to electric heat. I'm plugged in at home so the heat pump should run. Is it possibly a bad thermostat and are there better thermostats out there to replace it with?

gcamper · 02-29-2020, 06:51 PM

When we use our heat pumps and they can’t keep up and the temp drops more than 6 degrees from the set point the gas furnace will come on to raise the temp to the set point. It will cycle like this 3 times before the heat pumps shut off. The gas furnace will run for I think 2 hours then the heat pumps will start to cycle again.

dirt40 · 02-29-2020, 07:22 PM

I brought it home from storage so we can use it for a few days and I understand about a heat pumps auxiliary heat but the set point on the thermostat is the same as the temp in the rv but when the heat cycles on its the gas furnace not the heat pump. The HP has come on but only occasionally... weird.

Ray,IN · 02-29-2020, 08:31 PM

Clean the contacts on the back-side of the 'stat and on the heat pump control board. They are low voltage and corrosion can easily break contact.

imnprsd · 03-01-2020, 02:01 AM

I think if your inside air temperature is lower than 38-40F then your heat pump will not run... and the system will default to the gas heater.

Once your inside air temp is above 40F then the heat pump will work.

Why?

RV heat pumps are not very efficient under 38F. So the manufacture builds these things to work best between 40F - 60F.

AFChap · 03-01-2020, 06:56 AM

Quote:

Originally Posted by imnprsd

I think if your inside air temperature is lower than 38-40F then your heat pump will not run... and the system will default to the gas heater.

It is the OUTSIDE air that matters, and varies with temp & humidity. In lower humidity the heat pump will work in the high 30's, but in higher humidity it locks out in ther low 40's

dirt40 · 03-01-2020, 07:23 AM

Thanks guys for the replies. Unfortunately it was prime heat pump weather here yesterday. Sunny and high 40's and it was 69 in the rv. Are there better thermostats available to replace this one? I don't get why I can't run the fan continuously. I like to do that at night for a little noise.

AFChap · 03-01-2020, 07:38 AM

You can run the fan 24/7 on any setting except heat. I have read of some replacing the t- stat with a Honeywell. Some searching of old posts will likely turn up some info on that.

indiana journey · 03-01-2020, 08:27 AM

When I start our furnace/heat pump I make sure that the thermostat is set at only about 4 degrees above the actual temperature in the MH. When I turn it on and the setting is more than 4/5 degrees the furnace will start before the heat pump. Start with the thermostat set at about 3/4 degrees above the actual temperature inside the MH, then adjust it upward as the temperature inside the MH rises until you get it to the desired temperature. The heat pump should be able to warm your MH without the furnace coming on.
Good Luck,
Indiana Journey

dirt40 · 03-01-2020, 08:51 AM

Quote:

Originally Posted by indiana journey

When I start our furnace/heat pump I make sure that the thermostat is set at only about 4 degrees above the actual temperature in the MH. When I turn it on and the setting is more than 4/5 degrees the furnace will start before the heat pump. Start with the thermostat set at about 3/4 degrees above the actual temperature inside the MH, then adjust it upward as the temperature inside the MH rises until you get it to the desired temperature. The heat pump should be able to warm your MH without the furnace coming on.
Good Luck,
Indiana Journey

I can't say that when we turned on the thermostat yesterday it was only 3 to 4 degrees above the temp in the rv. But when I noticed the gas furnace was running was when it was 69 in there and it was set at 69. I turned off the gas at the tank when I went in for dinner and when I came back out it was 63 in there and nothing was running. I understand furnaces and heat pumps and work on a few of them in my profession, so know the temperature differential to keep the second stage heat from coming on.

imnprsd · 03-01-2020, 10:14 PM

Screw it! Get a floor heater and save your "system" for days when you need an air conditioner.

I would also recommend you get a 12x12 cube-heater so it does not fall over and break the safety mechanism built into all floor heaters. I.e., the cube type will not fall over and will last longer.

.... But yes, you can search for threads on upgrading your thermostat with an Ecobee or Nest, but you better make sure you know how many wires your current thermostat needs or you need to be prepared to rewire it.

My 2004 Itasca "Horizon" 40AD has 12 wires to the thermostat. Alternatively, you can order a new stock thermostat on Ebay for less.

Note: You might find if you clean your thermostat contacts with electric contact cleaner you will get better results. Try that first before you sink $100 - $200 into a repair. After all, it is an RV.

But if you want to get fancy there are Alexa controlled thermostat out there and you can switch these on using your cell phone.

So it's up to you. How far and how much do you want to spend?

DancinCampers · 03-02-2020, 06:21 PM

I would first remove the tstat fuse and see if it would reset.

You do not have control of the fan in electric heat mode because in heat pump mode all control is handled by the PC board once the tstat calls for heat.

The tstat monitors the heat pump operation.

I think the tstat is not recognizing the heat pump is there.

dirt40 · 03-03-2020, 07:31 PM

So yesterday I went out and turned on the heat and set it one degree higher than what it was in there. The heat pump came on and ran for a while until it satisfied. Then the gas furnace came on...ugh.

imnprsd · 03-04-2020, 12:21 AM

Dirt40: What type of AC/heat pump are you working on? Is it a basement type AC (2-ton unit)?

Have you tested the AC function just to see if your compressor(s) come one and stay on?

=== Questions For The Experts ===

Can someone tell me you need both compressors working in order for the heat pump to function?

And if you have one bad start capacitor... will this cause the problems Dirt40 is experiencing?

...Are these questions relevant?