Furnace quirks

Comanchecreek · 07-13-2017, 08:22 AM

The furnace in my Crusader starts up Okay but you can hear the burner kick on then turn off 5 to 10 times before finally staying on. Acts this way every time. Have a Dometic. thermostat. Not sure where to start or if it is actually a problem. Any ideas would be appreciated.

5picker · 07-13-2017, 08:24 AM

Is this on initial start-up or every time it calls for heat?
If just the first time, there may be air in the propane line that needs purged before it will light full flame.

007matman · 07-13-2017, 08:31 AM

Quote:

Originally Posted by 5picker

Is this on initial start-up or every time it calls for heat?
If just the first time, there may be air in the propane line that needs purged before it will light full flame.

Yeah, I wonder about a potential leaky/bad valve too which could be the issue if it's every time (it would be worse the longer it was in the off position).

Or, I know that the fridge has a flame sensor. I bet the furnace does too- Could be bad or like my Dometic fridge have a bad control board that doesn't tell it it's lit.

Comanchecreek · 07-13-2017, 09:05 AM

Quote:

Originally Posted by 007matman

Yeah, I wonder about a potential leaky/bad valve too which could be the issue if it's every time (it would be worse the longer it was in the off position).

Or, I know that the fridge has a flame sensor. I bet the furnace does too- Could be bad or like my Dometic fridge have a bad control board that doesn't tell it it's lit.

So I also have a post on my refrigerator not relighting. I actually suspect a propane regulator issue, but water heater and stove both seem to work fine. Furnace is an every time event. Sometimes it only takes it 4 or 5 times. others it goes on 10 to 15 times. May have more than one issue just picking your brains and experience.

Comanchecreek · 07-13-2017, 07:19 PM

It may turn out that my bottles were in changeover from left to right. I think my pressure drops to the point that things won't light properly. Thought it should just switch but may not.

5picker · 07-13-2017, 07:36 PM

It should switch OK provided the reserve tank is on. And once it changes over, you manually turn the lever/knob to the reserve tank (to then make it the main tank) and you start all over.

What happend once you turned the lever/knob on the change over?

Comanchecreek · 07-13-2017, 08:25 PM

Quote:

Originally Posted by 5picker

It should switch OK provided the reserve tank is on. And once it changes over, you manually turn the lever/knob to the reserve tank (to then make it the main tank) and you start all over.

What happend once you turned the lever/knob on the change over?

Reserve tank is on. Still acting up. Will have to check burner and igniter for issues. Also may be a thermostat issue.

5picker · 07-13-2017, 08:39 PM

Light all burners on stove so all are on high. Turn on furnace and observe stove burners. If one or more go out (or very low) you have a propane delivery problem.

I've only ever seen one furnace in a slide (it was a nightmare) but if it happens to be, check to be sure there's no kinks in the flex supply line.

Comanchecreek · 07-14-2017, 07:57 AM

Quote:

Originally Posted by 5picker

Light all burners on stove so all are on high. Turn on furnace and observe stove burners. If one or more go out (or very low) you have a propane delivery problem.

I've only ever seen one furnace in a slide (it was a nightmare) but if it happens to be, check to be sure there's no kinks in the flex supply line.

Not in a slide (Can't even imagine that one ) Will try the burner test. Working better since I switched bottles. I think each bottle has it's own regulator. Have noticed what I call the singing regulator.

So checked and do have a regulator at each bottle. Switched over and problem seems to be gone. Still not sure if it's the regulator or the bottle running out but usually just switches over without issue. Will have to see if it crops up again.

**Flybob** · 07-14-2017, 08:18 AM

There is a small thermocouple in the stack that senses the flame. If there is dirt, spiders or it is misaligned, it will not sense properly and may need several lights to get hot enough to decide there is a flame. I would check the thermocouple.

5picker · 07-14-2017, 08:31 AM

Quote:

Originally Posted by Comanchecreek

Not in a slide (Can't even imagine that one ) Will try the burner test. Working better since I switched bottles. I think each bottle has it's own regulator. Have noticed what I call the singing regulator.

So checked and do have a regulator at each bottle. Switched over and problem seems to be gone. Still not sure if it's the regulator or the bottle running out but usually just switches over without issue. Will have to see if it crops up again.

Most 5th wheels that come with two bottles, (one on each side) have the auto-change over regulator at one bottle and then usually a red step down regulator on the opposite side. It's designed to lower the pressure in the cross over hose. I've read about complaints of the red regulator going bad.

I've also seen reports where the cross over hose has collapsed inside (blocking flow) and the same for the short whip hoses at the tanks. I 'think' I've read where some of the whip hoses have check valves in them that went bad too.

If everything works OK until it changes over, I'd be looking at the supply chain to the secondary tank.

dwayneb236 · 07-14-2017, 08:38 AM

The regulator on my passenger side away from the auto change went bad. Was pretty obvious something was wrong with it when I had put a full bottle on it the trip before and never used it, but it was empty when I next checked it. Bad leak and there goes 30 lbs of propane.
Dealer fixed and all is good. Partly my fault because I forgot to close valve on tank when put in storage. If it had been closed would have been no loss. Oh well, live and learn.

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