Atwood furnace not igniting

[dcrawdad]

Hi, I have a 2004 jayco jayfeather 23b, and my atwood furnace , model 7920--II is not igniting. Blower turns on, but does not ignite. I am hooked to shore power. It has worked recently, kicked on a couple times this trip even. My battery is dead, but I think it has been dead all trip. Is battery necessary if connected to shore power? Furnace has a reset/off switch, but that has not been successful in troubleshooting. Any ideas on what might be going on? I hear it clicking and trying to ignite, but it does not kick on the heat. I have gas, stove works. Fridge on gas works. Thanks in advance

 

[parrott]

Hi, I have a 2004 jayco jayfeather 23b, and my atwood furnace , model 7920--II is not igniting. Blower turns on, but does not ignite. I am hooked to shore power. It has worked recently, kicked on a couple times this trip even. My battery is dead, but I think it has been dead all trip. Is battery necessary if connected to shore power? Furnace has a reset/off switch, but that has not been successful in troubleshooting. Any ideas on what might be going on? I hear it clicking and trying to ignite, but it does not kick on the heat. I have gas, stove works. Fridge on gas works. Thanks in advance

Has it been raining? The biggest culprit of the furnaces is the control board getting wet. If it’s trying to light the fan is running fast enough to trigger the sail switch. Try taking a hairdryer and drying the control board. You actually need a good battery too.

 

[dcrawdad]

Rained lately, but problem started before the rain. If hooked to shore power, do I still need a battery?

 

[ultrarider-JAY]

I’ve had some intermittent problems like that with mine. Disconnect the thermo fuse link, and clean the connector of both ends real real good. Use a finger nail grit file. After cleaning mine to the bare metal again, it’s been igniting fine. Worth a shot

 

[Jagiven]

Legally to tow, you need a good battery, for the emergency brake system.

To run the furnace you do not need a battery, just a good 12V power source such as your converter.

I have the same furnace in my 2012. I suspect the blower will run for a 20-30 seconds then the furnace shuts down, before ignition. If I am correct the issue most likely is the sail switch, not confirming the fan is working. The sail switch maybe dead or just dirty.

I have not removed my sail switch. I thought about cleaning it a couple weeks ago. It looks like you can access it, without removing the furnace. But it is not super easy looking. My Owner's manual, state the sail switch wires are white. But mine are bright blue. From the correct angles looking through the duct port you can see the switch, it is under the fan assembly. If you have a multimeter, it is a super easy test to check, without removing the switch.

To access the switch, on most RVs you need to remove the furnace. I do not believe that is required on a 23B. With the drawer above the furnace removed. Remove the HVAC duct that is over the pump. You just have to rotate it until the tabs line up. Take your time rotating the duct. May need to try both directions. Remove the wood divider between the pump and the furnace. Mine is held in with a single screw.

With the duct and drawer removed, you can see the sail switch (with a flashlight). Look down thought the duct connection, down under the fan assembly. My sail switch assembly is white, with a pair of blue wires (OM says white). As I said I have not removed mine, but I have looked at it closely.

You need to remove the fan assembly. One screw (1/4" socket head Phillips) will be a slight challenge to get to, as it is down low, right next to the wheel well. If you cannot access it, you will then need to pull the furnace. If you have the right tools you should be able to access it. There are 3 or 4 more screws holding the fan assembly in place. There is plenty of room to pull the fan unit out. It looks like there is one more screw to remove the sail switch assembly from the furnace box. It is below the fan assembly and behind the "air tube".

You may just get lucky, and it just needs to be cleaned and re assembled. But then, it maybe dead and need to be replaced. I would not recommend bending the long probes. They are what catch a the air flow, and apply pressure to satisfy the safety circuit.

If you do not have a copy of the manual, you can view and/or download a copy here;

https://www.manualsbase.com/manual/...ucts/atwood_mobile_products_furnace_7920-ii/#

Error codes from page 4

 

[ultrarider-JAY]

I’m sorry. I thought it was the hot water heater that was problematic. My bad. Disregard my input above

 

[dcrawdad]

Furnace is working now. I was not getting battery power due to some corrosion at terminal and blown in line fuse. I addressed both and now furnace is working again. Nice when you get the easy fix

 

[Jagiven]

Furnace is working now. I was not getting battery power due to some corrosion at terminal and blown in line fuse. I addressed both and now furnace is working again. Nice when you get the easy fix

That was an easy fix. Pulling the Sail Switch usually is not.