WH pilot, yes; burner, no ... HELP

[OregonArgy]

After reading the many threads on the pilot not lighting I got to work because I had the same problem. I've got the original Bowen from my 1978 Argosy 6-Metre TT.

Just today I replaced the thermocouple with a new one and used compressed air to clean out the pilot gas tube. I reattached everything and have gotten the pilot to remain on, YEAH! Well, at least as long as I keep the dial set to "Pilot." However, the pilot blows out the moment I turn the knob to the "On" position. I'm not sure why this is, but it is getting really annoying and I hope not to have to replace the unit, itself.

Any ideas? Thanks! Let me know if pictures would help!

[TomW]

It sounds like you have a weak pilot light. The flame is strong enough to get the thermocouple's attention, but not strong enough to handle the draft when the main burner valve opens.

The pilot light's gas may be adjustable, but I would recommend taking the pilot light jet out and soaking it in solvent overnight. The blow it out (from the top) with compressed air or carb cleaner.

Tom

[OregonArgy]

Originally Posted by TomW

It sounds like you have a weak pilot light. The flame is strong enough to get the thermocouple's attention, but not strong enough to handle the draft when the main burner valve opens.

The pilot light's gas may be adjustable, but I would recommend taking the pilot light jet out and soaking it in solvent overnight. The blow it out (from the top) with compressed air or carb cleaner.

Tom

Well, I just turned the pilot juice up as much as possible (by opening that little screw cover and turning the littler screw as far CCW as it would go). I already did blow through the tube.

Now, I'll tell you what. The design of the pilot tube dictated that it take a sharp 90-degree turn because of the burner tube and the pilot tube isn't quite kinked, but certainly not pristine.

One more detail...the pilot goes out just about 10% of the way from "pilot" to "on" on the dial. Just as I turn the dial away from pilot it goes out.

Do any of these details change your answer, TomW?

[Beginner]

Have you checked the gas regulator at the gas bottle to see if it is putting out the right pressure?
Beginner

[OregonArgy]

Originally Posted by Beginner

Have you checked the gas regulator at the gas bottle to see if it is putting out the right pressure?
Beginner

No, I haven't, but all of the other LP appliances work fine and I have one of those pressure sensors that tells you when your tank is getting low and it is on full green. I suppose there could be a compressed pipe somewhere down the line, but I gave a cursory look under the pan ad didn't see anything.

One more wrinkle... I went out just now to check the pilot and try turning it one one more time. Instead of there being a pilot light, I had an orange flame coming out of the compression fitting where the pilot tube goes into the main box. I must not have screwed it all the way in, but I sure thought I had.

I'm getting very frustrated and wondering if I ought to just bring a small microwave for hot water to drink and take showers in the camp bathroom.

Ultimately, I may need to purchase a new one, though I'm concerned about the amount of demolition needed to get the old one out and the new one back in. Any thoughts on that?

[overlander63]

Originally Posted by OregonArgy

One more wrinkle... I went out just now to check the pilot and try turning it one one more time. Instead of there being a pilot light, I had an orange flame coming out of the compression fitting where the pilot tube goes into the main box. I must not have screwed it all the way in, but I sure thought I had.


Ultimately, I may need to purchase a new one, though I'm concerned about the amount of demolition needed to get the old one out and the new one back in. Any thoughts on that?

We had that issue with the water heater on our Argosy, it turned out the selector knob was not quite where the pointer was. It worked fine when I turned the selector knob from "pilot" almost to "heat".
You can also check to see if there are mud dauber nests in the combustion area inside the heater, lack of draft would cause the flame to blow out.
As for demo, I've replaced water heaters on several rv's, and it's not that bad.

[OregonArgy]

Stupid question: Is paint thinner a solvent? Is it suitable for soaking the pilot tube?

I doubt we have mud daubers in the northwest. Thanks for that thought, though. :-)

I might just consider buying new. House WH's don't often last past 20 years and this one is 30 years old. Granted, only used seasonally, but still, it's been truckin' a long time.

[TomW]

Paint thinner is a solvent. It might be kind of slow for this application.

An appropriate solvent would be lacquer thinner. Acetone would would also work.

I would love to visit Oregon at some point - It is vastly different than what I am used to. But the Southern Belle I married has not, as yet, jumped at scheduling a trip there.

While Oregon may not have mud daubers, there might be some other insects in your area that can nest in the tube and cause trouble.

Tom

[Smokin Camel]

Originally Posted by OregonArgy

Stupid question: Is paint thinner a solvent? Is it suitable for soaking the pilot tube?

I doubt we have mud daubers in the northwest. Thanks for that thought, though. :-)

I might just consider buying new. House WH's don't often last past 20 years and this one is 30 years old. Granted, only used seasonally, but still, it's been truckin' a long time.

Try brake cleaner.

[OregonArgy]

I will try lacquer thinner since I can get it at Home Depot.

And, Tom, check out this thread for a small description of many places around the country and my quick description of Oregon:

http://www.airforums.com/forums/f161...ing-41394.html

[BillTex]

Is there water in the tank?
If not, the pilot will extinguish before it gets too hot...

Fill with water, open the pressure relief valve to be sure it is full, the re-light.

Bill

[doorgunner]

I put a half of a dog flea collar in the water heater compartment, the other half in the fridge area, no bugs, wasps,spiders, dubbers or anything else, change it every so often.

[floyd garver]

Is there a chance that you over tightened the thermo coupling ? I usually tighten them just past snug.

[genearnold]

I know Boise's climate is different from Portland, but we're in the Northwest . . . and we have mud daubers here. They fill up available holes on my BBQ, doors, etc. And I've had a lot of holes filled up on my Airstream.

Last fall I had problems when my front furnace wouldn't light. It turned out to be a very tiny spider in the orfice.

Gene

[OregonArgy]

Originally Posted by floyd garver

Is there a chance that you over tightened the thermo coupling ? I usually tighten them just past snug.

I had no idea one could over-tighten. I am sure that I tightened and then tightened some more. I'll be going back in there because I will be soaking the pilot tube. Should I loosen that back up and then only tighted a little. Thanks for that heads-up, Floyd.

[OregonArgy]

Originally Posted by BillTex

Is there water in the tank?
If not, the pilot will extinguish before it gets too hot...

Fill with water, open the pressure relief valve to be sure it is full, the re-light.

Bill

I definitely have the tank filled. I didn't want to even touch the WH until I knew the whole plumbing system was A-ok and the WH full. As far as pressure relief valve, I didn't know you ever had to mess with that. Is that the one upper-right, above the burner unit? Not the drain valve at the bottom left, BillTex?