Furnace Not Lighting

cgunn

cgunn

Well-known member
My furnace has just recently started doing this...
My thermostat will click and the furnace fan will come on but
after about a minute it will cut off because it wont light.
I had this to happen before when I was out of propane.
That's not the case this time as both bottles are full.
What should I be taking a look at??
We just recently arrived at our new campsite in Colorado.
We did use the furnace at a couple of RV parks on the way here..
It's been working just fine until now.
Has anybody had this problem???
If so what was the remedy??
Thanks..
 
Ray LeTourneau

Ray LeTourneau

Senior Member - Past Moderator
Charlie, Have you tried lighting the stove top burners? Another possibility, try resetting the OPD valves on both LP tanks. To do this, on each tank, close the valve and remove the hose connection. Re attach the hose and then SLOWLY open the valve. It's rare, but a bump or jolt can trigger the OPD device in an LP tank. If neither of these sugesstions work, I would suggest a professional.
 
J

JDR

Member
We had the same problem with or 2011 3670. We went through the gas checking, the problem is the sail switch. In our case it was sticking, if I taped it it would work fine until we moved locations, then had to tape the fan cage again. Talked to my Dealer he duplicated the problem confirming the sail switch and sent me a new one. I have not recieved it yet, but expect it will cure the problem.

Dale
 
J

Jimmy

Well-known member
Make sure you have not had a mud dobber (wasp) fill one of the air tubes with mud... Keep us posted.
 
jnbhobe

jnbhobe

Well-known member
The best way I can explain it is a switch in the exhaust tube that shows there is unrestricted air flow before the furnace can lite
 
ihsolutions

ihsolutions

Well-known member
I have had this problem with my 2011 3670 since new.

The first night I stayed in it at the dealer (in March) I nearly froze to death. The next morning they said "works fine now".

It happened again camping on a cold night in April. This time I was prepared with an electric space heater for the bedroom.

General RV could not replicate the problem in May when I took the unit in.

Yesterday, it got cold again and guess what, no heat. Fan comes on for about 30 seconds then the unit shuts off. This only seems to happen when it's cold. The unit is going in next Monday, so I will be sure to mention the sail switch. Not sure what cold temperatures would have to do with that sticking, though...
 
cgunn

cgunn

Well-known member
Jeff...
Mine was doing the exact same thing.."Fan comes on for about 30 seconds then the unit shuts off"
To make a long story short...
We found that the wires going to the limit switch on the end of the heat exchanger were too tight and
rubbing through the insulation and shorting out. After gaining a little slack in the wire so it doesn't rub anymore
the furnace works just fine. I did a continuity check on the "sail switch" & "limit switch" first to eliminate them.
We thought it was gonna be a "board" at around $130 but I got lucky and it was just an intermittent short.
Happened to me after a long road trip......Hope yours is just as easy a fix...
If you are taking your unit in be sure to mention those wires to them....They shouldn't be THAT TIGHT.
If you have any questions shoot me a message...
Happy Travels....charlie
 
RoadJunkie

RoadJunkie

Well-known member
To expand on Sail Switch:

To ensure the heat box does not over heat due to a lack of air exchange, there is a interlock switch that senses air flow. For example, if the fan is not working--thus no air exchange--the interlock will prevent the furnace from lighting. However if the sail switch fails, and even though it appears to have air exchange, the furnace will not light. Put yet another way:

http://en.wikipedia.org/wiki/Sail_switch
 
ihsolutions

ihsolutions

Well-known member
Well after another weekend of FREEZING TO DEATH camping, I can report that, again, my furnace is still not working. It worked before the trip, and also once I got home, but not DURING. Frustrating.

Today it went into the dealer, who said they are once again unable to replicate the problem. I explained everything mentioned above in this thread, and they basically said, if the furnace works, Heartland will not authorize any investigation or repairs into the cause. Once they are able to replicate the issue, they will go further, but not before.

This is driving me nuts. We are going on a 2 week, 2000+ mile trip in early November and it really would be nice to have functional heat, especially since several nights we will be without shore power (hence, no electric space heaters).
 
RoadJunkie

RoadJunkie

Well-known member
It sounds typical that some malfunction magically corrects itself just as a dealer shows up to confirm the problem. If it's at all possible, I would suggest you plan another short trip--before your November trip--to either gain confidence in the furnace or allow the furnace to develop a hard failure. Either way you're likely to be more relaxed about future heater performance.
 
Pizzaguy

Pizzaguy

Well-known member
We had the same problem first trips out this spring in the new BH. As the furnace was trying to light, I switched the water heater to gas instead of electric. The furnace lit right away every time I did this.Turning the stove on was not enough of a demand to get it to light.Replaced a faulty regulator/changeover valve and it has worked perfectly ever since.
 
W

Willym

Well-known member
As previously mentioned, you may have a sail switch, or sail switch wiring fault. This could be intermittent, with road vibration causing it to fail and clear. Has your dealer checked the wiring and switch? It would be a fairly simple check. A good dealer should believe you when you tell them that you have an intermittent fault and conduct an investigation.
 
chris4905

chris4905

Member
To expand-expand on the sail switch....

[SIZE=+1]Sequence of operation[/SIZE]
This is generic and applies to most DSI model furnaces.

  • Thermostat calls for heat.
  • Thermostat relay or time delay relay is energized and allows power to the blower.
  • Blower motor runs up to speed.
  • Sail switch closes at 75% of rated blower speed.
  • Power goes through the limit switch to the ignition control board.
  • The control board begins trial for ignition, opening gas valve and initiating ignition spark.
  • Burner ignites.
  • Thermostat reaches setting and opens.
  • Burner shuts down.
  • Fan runs briefly to cool furnace.
[SIZE=+1]Definitions:[/SIZE]
sail switch - micro switch with an arm that extends into the blower air stream which closes when the blower reaches approximately 75% of its rated speed. Also called an air prover switch.
 
sjrellis

sjrellis

Well-known member
I don't really know what I'm talking about and Jim is unavailable to ask him right now...but...we've had problems several times when heater fan comes on, but it never ignites. After resetting it a few times it will usually light. We had a service tech come out and he blew out the gas line (?). I guess condensation forms in the line(?) This same thing happened a few weeks ago and Jim blew the lines out (I think he used a really small air compressor). It has works just fine since then. Sorry if I sound totally like I don't know what I'm talking about...but, maybe this could be something to check into...as long as you can make SOME kind of sense from this gibberish. Ok, I'll stop now before I hurt myself.................
 
olcoon

olcoon

Well-known member
We were having the same problem with our Elk Ridge. Went to Colorado for a month & the furnace wouldn't work. Had a space heater so all wasn't lost! Took it to the dealer when we got back, and they had to replace the board. Glad we are still under warranty!!!
 
M

MikeW

Member
I had a similar problem. Took it to the dealer --- he pulled the furnace, and it worked perfectly. Told me that the LP tank was empty. When I went to pull the tank, it was way too heavy to be empty, so I switched the gas back to this tank, and all worked fine all summer long. Last week, mid 40's in Kentucky --- I'm pretty sure that I figured it out. All burners on the stove worked fine, but once again, the furnace wouldn't light. I went out and manually switched the regualtor, and could hear the gas begin flowing. Turned the furnace on, and it worked the rest of the week off of that side of the regulator. (Yes, it is a pain to swap tanks manually --- they NEVER run out in the daytime!) Right now, my bet is a bad regulator. I've switched it out, and have both tanks full, waiting for the next trip. (The probable bad regulator, is the type with the top green/red rings.)
 
A

alicia

Member
We are having the same problem of the furnance working great, then one morning it does not work. I will have my husband try some of these ideas, can someone please tell me exactly where the sail switch is located? We don't know exactly where to look.

Thanks,
Alicia
2009 BH 3055RL
 
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