No Heat

[Landcruiser]

Hello,

Thought someone might be able to steer me in the right direction, or have the answer. I have a DFSD20111 furnace that just started blowing cold air. The control board blinks 2 times then pauses for 3 seconds. This indicates a hard reset so I pulled the fuse to reset it. Same problem. I then purged the LP to confirm gas. Same problem. I called Oliver and Dometic but its Sunday and I can't get any tech support. Thinking it might be the igniter, was going to start checking for power at the connectors, then maybe remove it and check continuity. Any thoughts, I'd like to at least find the problem today. 

Thanks, Peter

 

[John E Davies]

I don’t have any specific suggestions, but this might help you get started. Good luck.

https://olivertraveltrailers.com/forums/topic/3248-how-to-service-your-furnace/

John Davies

Spokane WA

[WhatDa]

#1 problem with the furnace is the sail switch. If it blows cold for 30 seconds and then shuts off - sail switch is the culprit.

[WhatDa]

Read a little more carefully, it looks like you are getting the flame sense falt. The thing to troubleshoot would be are you getting ignition and it is the sensor or is ignition not happening?  John's link goes into viewing the flame - but you should also be able to hear the light off.

[Landcruiser]

Thanks, I'll check it out! I checked the sail switch, and cleaned it, looks like it works. No light off for sure. I'll read that like John sent thanks again.

[WhatDa]

From the light code. you are getting it doesn't sound like the sail switch, but you can time the blower run just to be sure.  No light off would be the ignitor (spark) or gas supply (more than likely the valve) or the circuit board that makes them dance.

[topgun2]

I don't think that it is sail switch either.  I've never had this issue with the furnace but have had a similar issue with the fridge.  I solved it by taking compressed air - a can of THIS kind of stuff is sufficient.  Be careful to NOT blow back towards the needle valve but do blow out around the burner, the igniter, and up the flue.

It doesn't take much dirt, dust, bug stuff to cause a failure on that igniter sensor.

BIll

[Landcruiser]

Thanks for the feedback guys. I figured for sure it was the board or the igniter. Like I said the thermostat initiated the furnace and the blower went on. The last thing I thought it would be was the T-stat. Well I did a reset on my T-stat today and the thing fired up I could hear the infighter and the flame. Here's a screenshot of the procedure. Wish I knew why this happened. 

Peter