How to get a/c fan off on heat

[masterdrago]

Something isn't right here. Maybe pics? Or, check with your service department. The furnace and AC blowers should not be running at the same time. There is something wrong with the system or user error.

I tend to agree that it is a "Grand Design" engineering flaw. There is absolutely no reason for the ceiling (A/C) fan to run during the heating cycle. Maybe if it were a heat-pump, which it is not. Again our Montana had a similar flaw. I've sent GD an email.

[Riverbug]

Even if it were a heat pump, it shouldn't run at the same time as the furnace. So I don't think it is a design flaw, I think it is a wiring or other issue. Will be interesting to hear what you learn. I hope I'm not wrong cause that would be weird if it is designed that way.

[jsm180]

If my fan is set to lo or hi the ac fan runs with the furnace, set the fan to auto and only the furnace fan runs.

[jsm180]

From the Dometic CT manual

"Furnace Mode
There are three fan speeds in Furnace Mode:
● “Low”: Fan operates continuously at low speed.
● “High”: Fan operates continuously at high speed.
● “Auto”: Fan is Off.
If additional indoor air circulation provided by the air conditioner is NOT desired during
Furnace Mode, select “Auto” in Fan Mode to shut the air conditioner fan off. If “Low” or
“High” is selected, the air conditioner fan will continue to operate at the selected speed.
In Furnace Mode the system cycles the RV furnace On and Off based on room air temperature
and temperature set-point on the CT thermostat."

[huntr70]

The one thing I HAVEN'T seen in this thread, and probably the most important fact, is what brand a/c and thermostat do you have?

Different brands operate differently, and it is impossible to answer your question without knowing what you have.

[bigjake392]

It is not a true thermostat as Petrovsky mentioned above. The actual thermister that senses the temperature is in the return box of the A/C unit. You can get a kit from GD to move it to a wall or they are also available to buy. I bought before I knew GD would send you one. I found that GD had run 7 wire thermostat wire to the wall controller so I mounted the sensor on the wall right above the controller and " stole " the extra wires from the controller and and connected from wiring in the control box to the wall sensor. Everything now runs as it should ..i.e.. like your residential system. Stupid design by Furrion and GD. Call GD and get a remote sensor kit. There are other posts on this same problem on the forum but my fix worked out perfect since GD used thermostat wire with extra wires. The kit has wire to run the sensor remotely but it would be exposed or somehow you would have to fish the wire in the ceiling to where you wanted to mount the sensor and that would be a chore. I would send pics but trailer is not close. The sensor and its wiring is clearly marked in the return box of the A/C unit.

[Dave & Robin G]

My 2021 2600RB is the same. There has been a lot of discussion about the AC fans running in conjunction with the furnace and it is due to the temperature sensor being in the AC unit. I don’t know if the 2022 is the same, but if you carefully pull the plastic grate off the AC unit (ceiling side) and remove the foam filter, you should find a wire (black I think) and it will be labeled “Temp Sensor” and pull that through the foam filter, put filter back in place, put sensor through the grate and put grate back in place, it will now do it’s job without the AC on. However, you say you only have “high” and “low” fan settings, mine has “high”, “low”, “auto” and “off”. When running the furnace I keep my fan setting on “off”. AC doesn’t run. Hope this helps.

[bigjake392]

I've seen where folks have just hung the sensor through the return grate of the A/C unit but you are still sensing up high for heat. If the extra wires are already available, its a simple fix to put the sensor on the wall above the wall controller and the temp is much more even and more like residential control. Like you said, the sensor wires are clearly marked and its easy to fish the wires 3 inches above the controller and mount. I wish I could show a pic but can't at this time. I really believe everybody would be happy with the way things work. By the way, this is with Furrion A/C and sensor setup.

[NDIrishLacrosse]

Lots of misinformation and guesses in this page. First question to the OP... is this a Furrion or Dometic unit? Given that they are referencing a 2022 Imagine, my money is on a Furrion, depending on what month they took delivery.

If so, GD no longer sends a temperature sensor relocation kit. What they do send is a new board and thermostat for the main AC unit (if you have two units). This started around July 2022. The purpose of it is to replace the heat only sensor for the Furrion units. When they were originally released, there were several reports of units sending heat out and it would not shut off because the sensor in the vents was not activated. This caused issues with people who left their pets behind. The immediate compromise was to activate the AC fans so air would pass over the sensor and show an "actual" room temperature. The replacements fix this issue where the heat sensor is located at the thermostat. The AC sensor, however, is not in this replacement.

It seems the OP got an Imagine when it was in between productions for the replacement board and controller. GD's answer was to run the fan automatically so the heat does not continuously run. This would stop the temperature issue. The OP should also see if they are running the dehumidifier setting. This would run the fan so the heat passes over the AC coils to dehumidify it.

Now, for the air conditioning: Furrion intended for their AC temperature sensors to be in the return and the unit should have the fan run all the time so the room temperature passes over it. People who do not run the fan constantly have found issues with their AC. This was mostly after Furrion produced these units and they were in the Imagines in the beginning of 2022's models. Furrion had the most availability for parts so GD switched. Some have had improvement with pulling the sensor thru the filter but one must be careful that the cover is not on backwards and air is being pushed to it (as was the case with mine).

Is this a good design? Likely not. But it is operating as intended.

[bigjake392]

Lots of misinformation and guesses in this page. First question to the OP... is this a Furrion or Dometic unit? Given that they are referencing a 2022 Imagine, my money is on a Furrion, depending on what month they took delivery.

If so, GD no longer sends a temperature sensor relocation kit. What they do send is a new board and thermostat for the main AC unit (if you have two units). This started around July 2022. The purpose of it is to replace the heat only sensor for the Furrion units. When they were originally released, there were several reports of units sending heat out and it would not shut off because the sensor in the vents was not activated. This caused issues with people who left their pets behind. The immediate compromise was to activate the AC fans so air would pass over the sensor and show an "actual" room temperature. The replacements fix this issue where the heat sensor is located at the thermostat. The AC sensor, however, is not in this replacement.

It seems the OP got an Imagine when it was in between productions for the replacement board and controller. GD's answer was to run the fan automatically so the heat does not continuously run. This would stop the temperature issue. The OP should also see if they are running the dehumidifier setting. This would run the fan so the heat passes over the AC coils to dehumidify it.

Now, for the air conditioning: Furrion intended for their AC temperature sensors to be in the return and the unit should have the fan run all the time so the room temperature passes over it. People who do not run the fan constantly have found issues with their AC. This was mostly after Furrion produced these units and they were in the Imagines in the beginning of 2022's models. Furrion had the most availability for parts so GD switched. Some have had improvement with pulling the sensor thru the filter but one must be careful that the cover is not on backwards and air is being pushed to it (as was the case with mine).

Is this a good design? Likely not. But it is operating as intended.

Well I hate to disagree with some of what you wrote but nobody designs an A/C unit to work with the fan running all the time. The sensor relocation in my Imagine , which was a simple fix , makes both the heat and A/C work much better. The fan is in auto so you don't have the noise all the time and the temperature is even. You have to direct one of the ceiling diffusers so it does not blow directly on the sensor, but again something simple. Sensing heat from the ceiling is not the way to go. My 5 cents worth after working in the trade for 35 years. Bad design.