RV Furnace Pilot going out

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  #1  
Old 10-08-03, 02:08 PM
dan62370
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RV Furnace Pilot going out

The pilot light on my RV furnace goes out. The flame lights fine; however after a period of time it goes out.

Last week it was going out every other day or once a day.

Now it goes out within 5-15 minutes of lighting it.

(I have been watching it now) Once the pilot is lit the flame seems to seperate from where the gas is coming out and ignites into a larger flame within the burner; and the pilot light goes out.

-------------

Steps I have tried...

1) Adjust the pressure going to the pilot flame. -- Higher or lower pressure doesn't seem to matter. (When at a lower pressure the flame takes slightly longer for the flame to go out.) However, the flame still ignites gas accumulating in the furnace and the pilot goes out.

2) I have taken the pilot light out to make sure it is clean. It looks fine (as far as I can tell). There are 2 holes in the end of the tube where the pilot flame is lit. Both are clear. That is the only part of the pilot gas tube that I have checked.

Thanks in advance for any help.
 

Last edited by dan62370; 10-09-03 at 03:32 PM.
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  #2  
Old 10-08-03, 10:25 PM
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Hello dan62370. Welcome to my Gas Appliances topic & the Do-It-Yourself Web Site.

RV heaters are very much like those found in homes and those used in mobile homes. Based on the problem description, I would suggest you first change the thermocouple.

The thermocouple is the most likely part to cause the problem, the easiest & least expensive part to replace.

However, bare in mind the thermocouple is only one likely part to cause the problem. There could be several other parts and or reasons and or conditions why the heating unit is not working as it should.

The thermocouple is the part the pilot flame is in contact with. The opposite end of the thermocouple is threaded into the gas valve. This end must be carefully unscrewed out of the gas valves control using a small open ended wrench.

A thermocouple is generic except for it's length. Measure the removed part or take the one you remove to any hardware store and replace it with an exact duplicate in length. The parts cost is very nominal.

New thermocouple packages will contain complete do-it-yourself installation instructions and pictures. The package also contains additional clips of various assortments.

Not all the parts contained in the package with the thermocouple will be needed. The packages contain an assortment of holding parts and clips that are generic and designed to fit a wide variety of applications.

Read the heating questions in the heating & cooling forum on the topic of heaters for additional information. Doing so will provide you with other problem possibilities and alternate correctional solutions to them.

If you need further assistance, use the REPLY button to add any additional information or ask additional questions after attempting the correctional method or methods offered.

Regards & Good Luck, Sharp Advice.
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  #3  
Old 10-09-03, 07:30 AM
dan62370
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Sorry...

Forgot to add in my first post that I had already replaced the thermocouple.

------------------------------------------------------------------------------------
It seems as if gas is leaking into the burner, and/or something is wrong with the pilot light.

The pilot flame gets bigger and smaller without changing the pilot pressure; and eventually ignites into a larger flame inside the burner. (The pilot flame goes out at the same time.)
------------------------------------------------------------------------------------

I don't see how this could be the thermocouple. Since all the thermocouple does is detect if the pilot light is on or not. Allowing gas to feed to the pilot light. Or turning off the gas if the pilot light is out.

The other thing that rules out the thermocouple is... that when the pilot light goes out; you can immediatly relight the pilot. Therefore gas is still being fed to the pilot light (i.e. the gas is not being shut off by the thermocouple because it is still warm - and working.)

Any other ideas???

Thanks,
--Dan
 

Last edited by dan62370; 10-09-03 at 05:11 PM.
  #4  
Old 10-09-03, 07:19 PM
DANSKOTA
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Exclamation

Had this exact thing happen to me on a week long camping trip. It turned out a spider had formed a cacoon in the end of the pilot tube. I had flame shooting out of the two holes that are intended to blend in fresh air. I took the pilot tube off and ran a paperclip thru the blockage.
Before dissasembling everything try this. Go to OfficeMax, Staples, are the like. Get a can of air spray...you know, the stuff they use to clean photocopiers. Stick the straw of the canned air into one of the two breather holes (this is where the flame is now forming). Plug up the other with your finger, and blow the blockage out. Hope this helps!
 
  #5  
Old 10-09-03, 08:49 PM
dan62370
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Thanks for the advice.

But.....
I have already had the pilot light assembly apart; and it was totally clean.



Any other ideas???? anyone???

Thanks,
--Dan
 
  #6  
Old 10-09-03, 10:23 PM
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Hi: Dan

Thus far we have established that the pilot assembly is clear and the thermocouple is new, properly installed, and being heated correctly by the pilot flame, we assume but cannot verify.

If all that is correct, there are several other possibilities. A pilot that snuffs out upon burner ignition, could indicate a weak pilot flame, incorrectly heated thermocouple, weak magneto in the gas valve, smothering flames in the firebox.

The last possibility is the dangerous and potentially hazardous condition. It is rather difficult to determine more accurately what the exact cause of the problem. Your problem description does not contain the right cause for me to determine the cause.

It seems as if gas is leaking into the burner
This is the statement of major concern and the one that does not allow me to more accurately determine the cause and the one that indicates a potentially serious condition.

This statement just adds to the doubts:

The pilot flame gets bigger and smaller without changing the pilot pressure; and eventually ignites into a larger flame inside the burner. (The pilot flame goes out at the same time.)
Based on the above, it is very difficult to determine why the pilot flame changes size. Who is checking and or changing the pressure and how is it being done???

If you're say pressure and meaning simply adjusting the flame by turning the adjustment screw, that is not changing the pressure. It is changing the volume. That's okay to do.

Changing the pressure via the gas controls internal pressure regulator without gauges attached and knowing exactly what is being done is dangerous and will effect both pilot and burners.

Very possible the unit is in need of a professional service persons inspection. Based on what the operating conditions are, as you described them, might be a wise idea to have the unit professionally serviced.
 
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