Furnace overheating

[Lynn1121]

I have a 2021Fuzion379. Furnace doesn’t stay on. I’ve had the dealership replace the furnace once under warranty. Now the second one is not working. Same issue. Dealership is stating that because the furnace is located under the shower floor in bathroom with no access to fresh air it’s causing it to overheat. There is an exterior vent for heater exhaust on outside wall of trailer by bathroom. Located next to fresh water tank filler. Anyone else having this problem ?? Anyone figure out a “fix”. Dealership is going to contact Keystone to discuss that it may be a design flaw and that they should fix it for free at this point. But I’m not holding my breath. Any help would be appreciated ! Thanks !

 

[NH_Bulldog]

That explanation doesn't really pass the smell test for me. Location of the furnace is largely irrelevant.

There is an exhaust and intake on the exterior of the camper for the furnace. It pulls in fresh combustion air and exhausts the byproducts of combustion to the exterior. It is a simple isolated system, and is VERY unlikely to cause anything to overheat.

While in operation, a blower pulls interior air (from inside the RV) and pushes it through a heat exchanger and out to all the ducts and registers. There is a return air grille (sometimes incorporated in the steps to the upper level of a 5th wheel, or can also be located in the wall behind the sofa). If there is a restriction of air going out (pinched ducts, blocked heat registers, etc.) or a restriction of return air (less likely, but possible), it will not allow enough air flow through the heat exchanger to keep it within operating specifications, and this will cause heat to increase to the point where the furnace will shut down.

I would check the airflow at each heat register and also locate and clear the return air grille.

 

[Mjhendy]

There is a temp sensor inside the furnace, if the temp inside the furnace gets too high the flame will turn off until the temp goes down. What could cause this is a pinched or blocked off heater duct.

 

[ChuckS]

The furance not only pulls air from the return vents..it also pulls air from underneath the flooring and coroplast area so it should be getting ample air to run properly

You have an Atwood furnace .. I would be looking at the plug in fuse in the power center panel for the furance

If it is black in color it is a resettable 12 VDC fuse that is prone to tripping .. remove that fuse and replace with standard style ATC fuse rated at same amp rating as the one in the panel

Try that and see what happens

If the problem, still occurs then located on the exterior case of that Atwood furance is a resettable switch ..

It is also a resettable breaker ( but not auto reset ) style. If that switch is tripping open it will also kill power to the furance

 

[Lynn1121]

That explanation doesn't really pass the smell test for me. Location of the furnace is largely irrelevant.

There is an exhaust and intake on the exterior of the camper for the furnace. It pulls in fresh combustion air and exhausts the byproducts of combustion to the exterior. It is a simple isolated system, and is VERY unlikely to cause anything to overheat.

While in operation, a blower pulls interior air (from inside the RV) and pushes it through a heat exchanger and out to all the ducts and registers. There is a return air grille (sometimes incorporated in the steps to the upper level of a 5th wheel, or can also be located in the wall behind the sofa). If there is a restriction of air going out (pinched ducts, blocked heat registers, etc.) or a restriction of return air (less likely, but possible), it will not allow enough air flow through the heat exchanger to keep it within operating specifications, and this will cause heat to increase to the point where the furnace will shut down.

I would check the airflow at each heat register and also locate and clear the return air grille.

That all has been addressed. No ducts are pinched and vents are not blocked. I’m waiting on another furnace to be installed and start the process again.

 

[Lynn1121]

The furance not only pulls air from the return vents..it also pulls air from underneath the flooring and coroplast area so it should be getting ample air to run properly

You have an Atwood furnace .. I would be looking at the plug in fuse in the power center panel for the furance

If it is black in color it is a resettable 12 VDC fuse that is prone to tripping .. remove that fuse and replace with standard style ATC fuse rated at same amp rating as the one in the panel

Try that and see what happens

If the problem, still occurs then located on the exterior case of that Atwood furance is a resettable switch ..

It is also a resettable breaker ( but not auto reset ) style. If that switch is tripping open it will also kill power to the furance

I have a Surburban furnace. There’s no access to this furnace unless you pull walls down. All vents and intake vents have been checked and rechecked. The furnace will work while being bench tested the. As soon as it’s put back into its closed compartment it stops working. Like it air starved.

 

[Rhagfo]

I have a Surburban furnace. There’s no access to this furnace unless you pull walls down. All vents and intake vents have been checked and rechecked. The furnace will work while being bench tested the. As soon as it’s put back into its closed compartment it stops working. Like it air starved.

How long does it run before shutting down? If you or the dealer thinks it is shutting down due to over heating then it should be running for at least five minutes.
The furnace being replaced should eliminate intake or exhaust blockage. Now the furnace also needs to move large volumes of air over the heat exchanger to keep it from overheating. Make sure that there is plenty of return air available for this exchange.

 

[Lynn1121]

How long does it run before shutting down? If you or the dealer thinks it is shutting down due to over heating then it should be running for at least five minutes.
The furnace being replaced should eliminate intake or exhaust blockage. Now the furnace also needs to move large volumes of air over the heat exchanger to keep it from overheating. Make sure that there is plenty of return air available for this exchange.

It’ll run about 5-10 minutes in the compartment before shutting down. I’m going to put vents in both compartment exterior access doors and a high and low vent where the furnace is located on the inside interior door wall. I have no other ideas on how to get more air for that closed interior area where the furnace was put. Thank you for your information. All ideas help.

 

[JRTJH]

Before cutting holes in the doors, have you tested the theory by operating the furnace with the doors open? If so, how long did the furnace operate before shutting down? If there was no appreciable extra time, then I'd guess venting those doors wouldn't make an improvement in furnace operation. Also, there were hundreds of that floorplan produced and not much (if any) complaints from other owners, so if the design was the issue, seems like others would be having "air flow/venting problems" as well. I wouldn't start cutting holes in things until you at least verify the holes would improve operation time....

 

[Todd & Mary]

There must be enough airflow thru the furnace to keep it operating at the proper temperature. if any of the ducts, return or supply are blocked it will cause issues. Mud daubers can also be an issue with the furnace exhaust outside.