Senaca Furnace is Stuck On

[TexasSeneca]

2016 Seneca with 6k miles on it

Tailgating today and my heating furnace seems to be stuck on

Turned both ACs off last and locked up the coach.
When I got to it this morning the heater vent was blowing full blast on the exterior of the coach.

Tried pulling the fuse, flipping breaker, turning off main disconnect etc. I pulled the fuse labeled "furnace" and it killed the furnace but also killed my front AC/thermostat.

ACs are both working fine and blowing cold air

Room temperature air coming out of the heater vents on the floor and the exterior heater vent continues to blow room temperature air

??????

[WaltW]

Whats the ambient temp? Is the thermostat set to heat and at what temp?
If room temp is more than 5 degrees below the setting, the furnace will turn on...it will not just run on heat pump until it gets within 5 degrees of room temp. The fans will also run when you shut the furnace off until the furnace cools down. If none of the above apply, it ain't working right.

[Robbbyr]

I concur with Walt. If it the thermostat is NOT calling for heat and the fan is running continuously you likely have a control board issue.

On my Seneca's Atwood furnace I can remove the 4 screws on the outside cover panel, and once the panel is off I can see the control board on the left-hand side of the furnace. It has a small red led on the board that flashes trouble codes when it senses a problem, yours might throw a code to help determine what is amiss.

Mine also has a on/off/reset switch outside under the panel. That switch also incorporates an internal circuit breaker according to my Atwood manual. Although I doubt turning that off then on would change anything, you might need to do that to trigger the control board into running another cycle to display any error codes if there are any. When that switch is off, my thermostats are dead, so they obviously somehow receive their 12-volts from the furnace circuitry. Good to know if the thermostats are dead but the power center fuse is good!

[WaltW]

I can't check my Seneca because Jayco has it right now but on my former Tiffin the thermostat had a fuse that had to be popped sometimes to reset it as it got messed up. Is there a fuse in the thermostat? Take the fuse out for a couple of minutes and see if that gets you back to normal.

[ohiocamp]

Originally Posted by TexasSeneca

2016 Seneca with 6k miles on it

Tailgating today and my heating furnace seems to be stuck on

Turned both ACs off last and locked up the coach.
When I got to it this morning the heater vent was blowing full blast on the exterior of the coach.

Tried pulling the fuse, flipping breaker, turning off main disconnect etc. I pulled the fuse labeled "furnace" and it killed the furnace but also killed my front AC/thermostat.

ACs are both working fine and blowing cold air

Room temperature air coming out of the heater vents on the floor and the exterior heater vent continues to blow room temperature air

??????

TexasSeneca I wanted to check and see if you found out what was causing your furnace to keep running, mine is doing the same thing, I pulled the fuse for furnace to shut it off.

ohiocamp
2016 Seneca HJ

[Crossingover]

Perhaps the gas orifice feeding the burner is clogged? Won't ignite yet the fan keeps blowing to meet t-stat demand? Should still be able to turn it off at the t-stat though.


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[Kerwin1959]

I had same problem. The circuit board outside had got wet from heavy rain. Had to replace board and they stood it up instead of it laying down also incase rain blew in again.

[Kerwin1959]

I also have 2016 Seneca.

[ohiocamp]

I tried turning it off with the T-sat and the only way to shut it off is pulling the furnace fuse.


ohiocamp

2016 Seneca HJ

[Kerwin1959]

In furnace cover outside is a switch that will turn it off and leave A/C heat strip controls on.

[RyRoRyan]

I had the same control board issue. Now mine does not actually fail to the point of having to be replaced, but I did find the design flaw...(for those who have fridges above their heaters).The heater itself it weatherproof sealed from the outside panel. It does however suck air in from the slats in the top of it. If you pull your outside fridge panel off, you will see a small gap between the wall of the coach and the plywood that the fridge sits on for all the wires and water line to come up through. If water gets near the fridge panel by blowing rain, standard rig washing or whatever, water WILL get in there and fall in that crack and then right into the top of the heater and right on the board. This has happened twice to me. The fix is like others have said to mount it up and down instead of flat, or build a cover for the board somehow. I have been lucky that both times, I just shut it down, pull the board out, blow it off with air, make sure there is no calcium or other water deposits on it and put it back in.

[javamon]

Originally Posted by RyRoRyan

I had the same control board issue. Now mine does not actually fail to the point of having to be replaced, but I did find the design flaw...(for those who have fridges above their heaters).The heater itself it weatherproof sealed from the outside panel. It does however suck air in from the slats in the top of it. If you pull your outside fridge panel off, you will see a small gap between the wall of the coach and the plywood that the fridge sits on for all the wires and water line to come up through. If water gets near the fridge panel by blowing rain, standard rig washing or whatever, water WILL get in there and fall in that crack and then right into the top of the heater and right on the board. This has happened twice to me. The fix is like others have said to mount it up and down instead of flat, or build a cover for the board somehow. I have been lucky that both times, I just shut it down, pull the board out, blow it off with air, make sure there is no calcium or other water deposits on it and put it back in.

Definitely checking this out this weekend. Thanks...this is excellent info!