Furnace turns on the air?

[Frank_K]

When I turn on the heat, both the furnace AND the air come on?
I turned off the AC breaker to kill the air but have no idea whats going on.
Same problem with both stats.

Frank
2013 Thor Palazzo

[Yvonnemarc]

No recent T-stat work / change? No heating elements in your AC units?

[javelin]

Welcome to the forum.

I am not familiar with the Palazzo thermostat(s) specifically (or any special heating/cooling units in that coach), but my first question is what work has been done if any recently that may have affected the thermostat wiring? Did you add move or change the thermo somehow?
When the thermostat calls for heat, typically the W terminal connected wire is energized with 12vdc, which is usually connected to the furnace. When the thermostat calls for cooling the Y terminal is energized typically, which operates a control relay to then operate the air conditioning compressor. So first guess is the W and Y terminals on one (or less likely, both thermostats) are shorted together somewhere. The other possibility is if you have two thermos wired in parallel, the W and Y terminals from one thermo are wired in reverse to the other thermo.

[Frank_K]

No work, no changes and no heating in the AC units.
Thanks

[Frank_K]

Yes, I'm familiar with the concept.
Any ideas on where the relays and control board are located in the 2013 33.1 Palazzo?
Thanks

[Beau388]

Originally Posted by Frank_K

When I turn on the heat, both the furnace AND the air come on?
I turned off the AC breaker to kill the air but have no idea whats going on.
Same problem with both stats.

Frank
2013 Thor Palazzo

Sounds like your thermostat has failed or the furnace and A/C thermostat wires are touching.

[dkoldman]

Originally Posted by Frank_K

Same problem with both stats.

Frank
2013 Thor Palazzo

Can you clarify...

I assume you have one Furnace Stat? Or are you saying you have two Furnace stats?

Can I assume Thermostat 1 controls the furnace and AC#1? Thermostat #2 controls AC#2.

Are you saying when Thermostat #1 is set where the Heat turns on, it also turns on AC#1 & AC#2? That does not seem right thus I am asking for clarification. Pictures of your thermostats would help.

The only thing we know for sure is that at least one outbound HVAC request from one Thermostat is sending to at least the #1 AC unit and the Furnace. If it is same wiring and same thermostats from original coach, then your thermostat w/Furnace has shorted someplace.

[gmadams]

Originally Posted by Frank_K

When I turn on the heat, both the furnace AND the air come on?
I turned off the AC breaker to kill the air but have no idea whats going on.
Same problem with both stats.

Frank
2013 Thor Palazzo

Is your fan set to Auto? If it is on either Low or High the AC unit will kick on when the furnace fires up.

[Frank_K]

That was the problem !
A big thank you to gmadams.

Frank

[simidrm]

check your thermostat settings and see if the heat is set to gas or electric.

If it is in electric then its using the a/c system as a heat pump.

[Frank_K]

No heat pump, see earlier post , problem was fans were not in auto, issue resolved by gmadams.

Thanks

[Badmanrick]

On some HVAC / furnace systems both the furnace and the A/C fans come on to circulate the hot air quicker. Those settings are adjustable. You must read the instructions. We have a 2019 Thor Hurricane 34j and it has the Firefly control system. When on auto settings both units come on with what the temperature is set at. If you change your settings to manual high or Low fan then only the furnace will come on.
Hope this helps.

[Junodtim]

I’m not sure about your set up, but the last two RV I’ve owned were made by Thor; and each of them had the thermostat wire cable connected to the air conditioner. The control board in the air-conditioner calls the furnace for heat when requested by the thermostat. If you haven't altered anything; maybe there is a broken wire connection, loose wire connector, or bad control board in the air-conditioner.

[Frank_K]

Is your fan set to Auto? If it is on either Low or High the AC unit will kick on when the furnace fires up.

[Tinman]

Had the same problem in my 2016 Palazzo. Turn the A/C controller to the “Fan” position. It will probably show “On” or “Low” or “High”. Use the up/down control to change it to “Auto”. Now the furnace will run without the A/C fans running too. Happy trails!