sdeeter19555
Shoemakersville, PA
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Joined: 10/12/2007
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Attempted to run the furnace last week...
I can get the pilot on and the thermostat will kick the fan on; however the actual burner won't kick on.
What in the workings of this furnace would cause it not to kick the burner on?
Thanks,
Steve
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ejforwood
Littleton (Denver) Colorado
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Joined: 04/26/2006
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The Sail switch seems to be the usual problem.
Next might be to check if the propane is reaching the burner.
Next might be the igniter.
If all these are functioning, check the circuit board.
Jerry, Dottie & Chan, "the little furry one"
98 Bounder 34V, 99 F-53 Ford V10 chassis
06 Saturn VUE 4I
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STINGRAYRVMAN
PANAMA CITY
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Joined: 08/16/2007
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Could be several different things.
1.There is a sail switch that will keep unit from lighting if enough airflow is not reached or switch can be defective. (not enough fan speed from bad motor or lack of voltage)
2. The igniter board itself could be faulty or in need of cleaning.
3. Mud daubers or hornets can nest in the burner assembly and keep furnace from lighting.
4. I assume you have checked your propane tanks and they are full and turned on and the LP regulator is not defective.
5. Plugged orifice on the furnace gas valve or a defective gas valve.
I will caution you that you should not attempt to work on a gas furnace unless you have been trained to do so. It is a simple designed appliance with several safety features but should not be worked on unless you are qualified to do so.
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javaseuf
Southern Cal
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The previous two posters didn't catch that your furnace has a standing pilot light so your model will NOT have an ignitor or a circuit board.
Three components in your standing-pilot Duo-Therm will cause the trouble you describe. They are the Sail-Switch, High-Limit Switch and Gas-Valve.
When the thermostat calls for heat and the blower activates, both terminals on the sail-switch and high-limit switch must have voltage to pass current to the gas valve. If the sail switch or limit switch only has voltage on one of its terminals, that component is defective.
If there is voltage present at both terminals of the sail and high-limit switch then go to the two 12 volt terminals on the gas valve. If those two have 12-volts but the valve is not opening, it is a defective valve.
Also note that you must have sufficient blower speed to properly activate the sail switch so low-voltage or a slow-turning fan motor could be the issue as well.
I would start at the gas valve and if there is no voltage, start with the sail switch. If you can manually push the lever on the sail switch and the burner then comes on, the switch could have dust lodged in the mechanism or the blower is not running at the proper speed which could be low-voltage or a bad motor.
HERE is the service manual for the 65000 series standing-=pilot Duo-Therm furnace.
Steve
2007 Springdale 291RKL
2003 F150 King Ranch
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lv2rom
Kansas City, Missouri
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javasuef got you on the right track, interesting how we all so quickly get caught up in the perpetual ignitor/control board issues...Brian
2005 F350 Dually -AFE air box/MRSP exhaust/Bags/Bilsteins/Energy Susp./Michleins
2002 Hitchhiker Fiver 29.5 RLBG - Moryde Pin/Gas shocks/Michelin XPS Ribs
1996 Layton Fiver 21ft. Totally reconditioned..Love it!!
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sdeeter19555
Shoemakersville, PA
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Thanks for that link...when these guys were talking ignitor, I knew that wasn't right.
can anyone point me to a wiring diagram for the electronics? So I can trace everything out...
The main fan was slow starting when I first kicked the thermostat on.
steve
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javaseuf
Southern Cal
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There should be a diagram pasted on the inside of the access panel.
I checked my old documents and couldn't find anything.
It sounds like you may have a bad motor. Whatever you do, don't try and compensate for the low air flow by adding more surface to the sail-switch. Low air-flow is a safety issue and if the sail-switch were to be modified, the heat exchanger could easily overheat and crack, therby allowing carbon-monoxide into the living area.
If you find that you do need parts, I recommend AAA Appliance in Sacramento, Calif. Even when I lived in your area and did RV service, I used these guys. They are great. I just hope that the blower motor isn't obsolete.
Good luck!
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javaseuf
Southern Cal
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sdeeter19555 wrote:Thanks for that link...when these guys were talking ignitor, I knew that wasn't right.
can anyone point me to a wiring diagram for the electronics? So I can trace everything out...
The main fan was slow starting when I first kicked the thermostat on.
steve
They were just trying to help and with electronic ignition being used in RV furnaces for the last 15-20 years, it is possible that many here have never seen furnaces, water heaters and refers that used constant burning pilots and burners.
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tuckerin
morristown, ny
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Joined: 09/28/2004
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Also the thermocouple could be in the low range of its output..enough to keep pilot lit but not enough to open main gas valve..
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javaseuf
Southern Cal
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tuckerin wrote:Also the thermocouple could be in the low range of its output..enough to keep pilot lit but not enough to open main gas valve..
The main gas valve is opened by a 12 volt solinoid. On a milivolt valve, the pilot generator/thermocouple does operate the main gas valve. On a RV furnace with a blower, it's 12 volts. The only purpose for the thermocouple in this application is to keep the safety magnet open for the pilot flame.
* This post was
edited 12/15/07 07:54pm by javaseuf *
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