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gcrank1
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# Posted: 20 Nov 2024 00:44 - Edited by: gcrank1
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My Dyna Glo 30k btu infrared wall furnace (bought new Dec 2020) has shut off on me a few times the past couple weeks. Each time it has been the same; this account is the most recent.
It started up great, the pilot lit right off and held, then I turned on Low/tile 1, let it burn a bit then lit off Med/#2 & 3, same result, then High/#4 & 5. Ran great.
It took the 52*f cabin to 72* in about 1 hr. We like it warm so I ran it up to 78* and set back to Med.... all was holding well so I set to Low to idle along.
It ran fine for about 15 min then I heard a bit of a roar, looked quick and saw the pilot flame had separated from the nozzle and was out by the thermocouple, then the gas valve shut down due to being too cool at the t-couple.
The safety shutdown worked like it should at the gas control valve.
It was comfy warm so I let it sit about 1/2 hr and tried a restart, no go, Id get enough pilot to act like it wanted to light but not enough gas to hold.
When this happened before I did some online research and most responses were 'replace the thermocouple'. This did not make sense to me as on a cold start up it works fine. In a cold start holding the pilot 'button' down it bypasses the t-couple valve in the gas valve, the pilot lights and holds proper flame, and all tiles/burners run while holding a fine steady pilot with the t-couple activating the gas control valve to open.
I pulled the pilot feed line and jet out, blew the line out then the TINY jet.
Testing the gas valve I confirmed that with the gas on, pilot control depressed, the pilot outlet at the gas control valve fitting flowed gas, control not depressed is no gas.
Put back together, all worked again, guessing the jet had a little plug in it?
Then the shutdown recurred again after a bit at the same Low setting.
This time I also pulled off the feed line from the inlet regulator at the bottom of the unit (btw, I do have proper drip/sediment leg below that inlet) and the gas control valve. Holding it to my mouth and the other end a couple inches from my palm and gave it several strong puffs. What looked like small water droplets sprayed into my palm!
I should mention that in the recent install of this unit into the new cabin I had checked the drip/sed leg and found nothing. I also had blown out every fitting and line I used (most were new for this install).
Put back together and runs fine.
Conclusion: Careful analysis of the symptoms kept me from just replacing what seems to be a good t-couple, which would not have solved the problem (like so many online who did replace and not solve their problem).
Next question is Why the moisture in the line? I expect I will need to pull sections of my supply apart to clean/blow out as this will likely recur 
Fwiw, on lp units with larger pilot jets the droplets may well have passed through. On this the jet is SO small that even a small dia. pin wont enter, I had to use a wire from my brass wire brush and a magnifier. I expect that one of those 'compressed air in a can' would maybe have back flushed it easier.
Hope it isn't moisture coming out of my old 120 Gal cylinder but where else could it be coming from?
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Brettny
Member
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# Posted: 20 Nov 2024 10:28
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You need a drip leg. Are you useing any type of rubber or stainless line in the system?
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Fanman
Member
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# Posted: 20 Nov 2024 11:35
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Is a new tank, and if so, was it purged and methanol added? My tank arrived vacuum purged, and the you're supposed to add some amount of methanol to absorb moisture. If it's vacuum purged, you just let the vacuum suck in the methanol. It's just like putting dry gas in your car and in fact I used automotive dry gas, which is also just methanol.
I have also heard of moisture being introduced while filling on a rainy day, though I've never observed it.
But your "bit of a roar" and pilot flame separating from the jet makes me wonder if you have a bad regulator, too-high gas pressure might do that.
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FishHog
Member
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# Posted: 20 Nov 2024 12:08
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take some fine sand paper and gently clean the part of the thermocouple that the fire is on. Small amount of bulidup/dust etc. can change the resistance and cause those issues. Was out in Alberta this spring at my brothers house and the furnace kept going out. That was my first step as its easy and its still running normal today.
If that doesn't work, then the above suggestions are good next steps. But switching to another tank and purging the line would be step 2 for me.
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gcrank1
Member
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# Posted: 20 Nov 2024 14:58 - Edited by: gcrank1
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Old 120gal/420#? upright cylinder, had it refilled June of 2022. I bought it used with about 40% and ran it with this heater through winter '21-'22 with no prob.
Ran it winter '22-'23 and '23-'24 with no prob.
In the back of my mind this past April? just as we were prepping to dismantle the old shack I sorta remember it 'popped off' but I was pulling it out anyway (so much has happened since then and Ive totally forgot it).
Yes, it has the proper (emphasis Proper) drip/sed leg.
And yes, there is a new rubber line from tank to the black iron at cabin wall.
The pilot flame is perfect when lighting up and initial running, even 2+ hours, then the pilot gets the flame separation (like lighting a cutting torch without enough acetylene cranked in) which isn't hot enough so the t-couple doesn't keep the gas valve open.
Im wondering if over time the piping has had enough internal condensation due to this being a rec use cabin and the heating/cooling cycles it goes through that the delivery piping and the pilot delivery tube plug the jet with a droplet.
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gcrank1
Member
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# Posted: 21 Nov 2024 00:48
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Went today, cabin at 44*f, unit fired right up and ran it on High for 1 hr, got to 72*. Set it down to Med and it ran for another 1hr 15min and shut down. Temp was a nice 77* though.....
Pulled the pilot delivery tube, the pilot jet and the delivery tube to the gas control valve.
The jet looked good but I ran the brass wire anyway.
Pushed a length of weed-wacker line through the pilot tube (snug fit), nothing found, then puffed on it too.
The main delivery tube (the one I got the spray of droplets from) is much bigger so I ran the line through and put a cloth patch on then pulled through; repeat 4x. Nothing seen on the patch.
Blew out the gas control valve.
Reassembled and turned on gas then ran the sniffer at all the disturbed fittings. All good.
I fully expected it to light off but No.....let it sit 1/2hr and the retry failed like it isn't getting enough gas to pilot up. (btw, this should have nothing to do with the t-couple as the push down pilot button bypasses/opens the gas control).
Bet if I went tomorrow it would fire right up again.
Next time Im going to run until shut down and quickly unhook the feed line and hook up my 18k btu 'blue flame' unit. Depending on how it runs will tell me if the regulator is ok.
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FishHog
Member
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# Posted: 21 Nov 2024 12:40
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that should be a good regulator test. Any chance it has an Oxygen sensor that is tripping off? Could be faulty, or you could actually be reducing the O2 enough during your initial warm up that its doing it job. Not sure how long they take to reset after tripping. Just brainstorming.
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