Barn Furnace won't fire. HELP

[xtremek]

Hi folks, I’m back again needing some help. I had the mechanicals guy come out and check over my furnace installation and get his blessing. Then I had the gas hooked up to the barn furnace and the system checked for leaks. I know (NOW), the wrong order. Anyway, I tried to fire it up and I’m having issues. I can light the pilot and get it to stay lit. The transformer has 27.4v coming out of it and I can get the blower motor to come on manually. But it won’t fire the furnace. I have an AirEase built by Johnson Corp., model number NAS100. I have the cheapest Honeywell thermostat Menards sells. If I jump the t-stat, the gas builds up until I have a small explosion and it knocks the pilot out. Definitely not lighting right. I think I have two issues, something wrong with the t-stat and maybe something wrong with the pilot placement? I did notice the t-couple line was pinched, but I’m guessing that would only cause issues with it turning off.

 

[fickster03]

I wonder if you got air in thr lines if it's freshly hooked up I had a problem with a small propane boiler at at ranch house I rented one time

Dixon Missouri. welder/rancher/heavy equipment

 

[xtremek]

I doubt it. I pulled the cap off the bottom of the drip leg until I saw fumes come out. And it's taken me many tries trying to diagnose the issue. But thanks for the suggestion.

 

[rlitman]

I wonder if you got air in thr lines...

Not if his pilot stays lit.

I'd check to see if the venturis are stuffed with something. Sounds to me like its starved for air.

 

[CoogarXR]

I am no furnace tech by any means, but it does sound like the pilot isn't close enough to the burner, or the orifices on the burner nearest the pilot are plugged.

 

[rlitman]

I also need to ask a dumb question. Are you sure the gas pressure is correct?
Do you know the pressure of your system, and whether or not a regulator is needed for each appliance?

 

[Richard Cranium]

I agree with CoogarXR.

 

[D45]

What temp is it in your barn?

What is the lowest temp on the thermostat?

I bought a "low temp" tstat for $22ish, that goes down the 35 degree........whereas most other tstats do not go that low

 

[gungatim]

LGR!

 

[matt_i]

Also worth checking...is there a blower which forces convection thru the chimney in advance of the gas valve going to high-fire? Seems like some kind of back pressure/flow resistance thru the chimney (like a dead bird in there) would prevent proper combustion from developing.

 

[xtremek]

Propane and I'm running off of the same tank as the house and it's about 75%. And there are 2 regulators. What's a carrier rail?

 

[xtremek]

What temp is it in your barn?

What is the lowest temp on the thermostat?

I bought a "low temp" tstat for $22ish, that goes down the 35 degree........whereas most other tstats do not go that low

Probably was 20's in the barn and the t-stat goes down to 50F. But won't that only deal with how often it kicks on?

 

[xtremek]

Also worth checking...is there a blower which forces convection thru the chimney in advance of the gas valve going to high-fire? Seems like some kind of back pressure/flow resistance thru the chimney (like a dead bird in there) would prevent proper combustion from developing.

I highly doubt there's a dead animal in the flue (i'd smell the rotting corpse, but I'll check to see if something might have made a nest in it.

 

[D45]

How far is the heater from the tank?

Are you certain the pressure at the heater is good enough?

When I ran 60 feet of pipe to my NG heater, only one burner was lighting

I left it running for about 30 minutes and finally all burners were firing. Been perfect since

I think I had too much air trapped inside the pipes

 

[xtremek]

About 40' from the tank to the furnace. I'm almost certain there's no air in the line. You can see the old beast below

 

[D45]

Having no air in the line is one thing, but having the correct pressure at the appliance is another

 

[gungatim]

LGR!

 

[Dr Stan]

The first items I would check are 1) thermocouple & 2) the thermometer.

 

[LS6 Tommy]

T-couple is good. The pilot stays lit. Gas valve is only on "Pilot" in the pic. Is it "On" now? Gas pressure correct? Proper orifice(s) for the fuel being used? Heat anticipator set correctly on T-stat?

Tommy

 

[brewchief]

Pilot is missing a screw and sitting crooked, that might be causing delayed ignition.

I would pull and clean the burners before I went much further as well.

It has been properly setup for LP gas correct?

 

[xtremek]

I was told the reason I got it was because the owner's new place was natural gas and it wasn't cost effective to revalve it. I straightened the pilot up and still no joy. Yes, I did move the valve to on, but I didn't want to leave it there for fear of another minor explosion. I also blew everything out with my air compressor (compressor regulator set at 150psi). If I jump the t-stat, I can hear the valve click, but no joy. When I shove the air nozzle into the burners, I can feel the draft coming through. What's a heat anticipator? I appreciate everyone's suggestions and help.

 

[tgb]

It looks like you are missing the burner crossover, those burners are to far away from the pilot to light, so the valve opens and builds up gas until it reaches pilot and explodes, that furnace is really old so you won't find a replacement for that part you will have to make one

 

[xtremek]

It looks like you are missing the burner crossover, those burners are to far away from the pilot to light, so the valve opens and builds up gas until it reaches pilot and explodes, that furnace is really old so you won't find a replacement for that part you will have to make one

Hey TGB, do you have a pic of this part? I'm ok with trying to fab something up.

 

[tgb]

No pic, but it would be a u shaped piece of metal that would go over the pilot and wing shaped part of the burner

 

[xtremek]

I checked the heat anticipator, and it's set correctly (I'm guessing that's where you set the t-stat according to the furnace and fuel type). Anyone know what the pressure should be and where I should check it? There's a pipe plug on the end of what I would call the "gas plenum"(?)

 

[D45]

There are some good Youtube videos on gas pressure testing these hanging units

You need a special tool, that will screw in a measure the pressure

I know on the valve on my heater, there is a inlet pressure adjustment and an outlet pressure adjustment, on both sides of the valve.......in addition to the test port for the pressure meter

 

[Pointbock]

A failed gas valve isn't impossible - flows enough to run the pilot but won't operate the burner. I had to replace mine at the start of last winter (old Modine heater.)

 

[xtremek]

Ok, so everyone can say I told you so now. I have the day off, so I had the time to pull the burners out. Some of them were filled with rust. Cleaned them up and I can play games and they will light. Then I took the thermostat apart and found a piece of paper insulating the switch. Remove the paper and the t-stat works fine. Back to the games. If I let the gas build up about 30 seconds, I can light it with a torch and it stays running for about a minute or two, then everything goes out, even the pilot. If I use the t-stat, the pilot flame gets really small and the I'm guessing the pressure's too low. I'm guessing it takes a special socket to adjust the regulator. I'm told I should set it at about 0.3 psi. Anyone know what the socket looks like?

 

[D45]

Have you tried also letting it run for 30 minutes, so purge air out of the lines?

 

[matt_i]

I'm going to respectfully suggest that its maybe time to let this furnace go. I do admire your willingness to keep hammering away and not giving up, but there's a lot at stake when a gas furnace won't go to high fire reliably.....all it takes is one non-monitored event, like if you left to go to the bathroom for a few minutes, and your entire shop could become a "do-over".

A new heater is a couple hundred $ new but consider that vs. cost of having a *big problem*. If you could mentally put yourself in that situation, I would think that you'd probably spend the few hundred in hindsight.

 

[xtremek]

I'm going to respectfully suggest that its maybe time to let this furnace go. I do admire your willingness to keep hammering away and not giving up, but there's a lot at stake when a gas furnace won't go to high fire reliably.....all it takes is one non-monitored event, like if you left to go to the bathroom for a few minutes, and your entire shop could become a "do-over".

A new heater is a couple hundred $ new but consider that vs. cost of having a *big problem*. If you could mentally put yourself in that situation, I would think that you'd probably spend the few hundred in hindsight.

I appreciate your suggestion, but a new heater is not a couple of hundred dollars, but a several thousand dollars. And your comment on safety is not lost on me. Until I see it fire consistently and safely, I shut everything down when I'm done tinkering. The t-stat issue was my fault for not removing the shipping insulator. If this turns out to be a pressure setting on the regulator, that too has nothing to do with the furnace, but again can be attributed to the loose nut behind the wrench (me). And my plan is to turn it off as I leave the barn for the day, since this is a low efficiency unit. I'll keep the torpedo to bring the barn up to temp and use the furnace to keep it there, But again, it'll need to operate safely, or down it comes.

 

[BillK]

x,
I am not going to suggest replacing the furnace but I do think its time that you call your Propane supplier and have them come out and check the entire installation and properly set the pressure etc. Maybe even pay them to service the furnace and get it running properly. Might cost a couple of hundred bucks but that's better than burning the shop down

 

[gungatim]

LGR!

 

[xtremek]

Ok, the valve has a yellow sticker on the side saying that it's "....been converted to run on LPG". The propane guys put a tee in after the red regulator on the tank with a ball shutoff valve. Then, where the line comes outside of the wall, they put a brown regulator. It then has a 10' run up the inside of the wall, a 30' run through the rafters and 2' drop down to the furnace. I've got a pic of the flames, they're small blue flames, about a 1/4" tall. As far as the orifices are concerned, they're more slots than holes and they were clogged, but I did clean them out completely. Before I cleaned them, the gas would build up in pockets until everything went BANG. Now, when I use the torch, it's a nice steady light off (fairly quick, but no big bang), so I'm pretty sure I got them clean. When I use the t-stat to try and fire the furnace, the pilot flames drop down severely. Again, I really appreciate EVERYONE's input.

 

[D45]

.........but a new heater is not a couple of hundred dollars, but a several thousand dollars.........

Craigslist is your friend

There are a ton of heaters all over CL for $100-$400, depending on the size

My Hot Dawg 45K was going for $300 on Craigslist, which I traded and basically got a $700 heater for free

 

[gungatim]

LGR!

 

[Pipe_guy]

Forums are good for lots of thing but I don't think trouble shooting a furnace is one of them. I think your best bet is to get a gasfitter there to test your pressure and look over the furnace. That's coming from a gasfitter. There are to many variables to speculate with out being there with your eyes on it. There is a safety aspect as well.


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[xtremek]

post up the model # of the brown regulator, the specs will tell if the vapor capacity is high enough for your 180,000 btu furnace.

also make sure the vent on the regulator is not plugged up. it should be facing down to keep water/debris out, and freely open.

It's a Rego brand and it's either a 1v4403 or Reg430. The regulator was just installed this past Saturday by the propane company.

Forums are good for lots of thing but I don't think trouble shooting a furnace is one of them. I think your best bet is to get a gasfitter there to test your pressure and look over the furnace. That's coming from a gasfitter. There are to many variables to speculate with out being there with your eyes on it. There is a safety aspect as well.


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I understand what you're saying, but so far all of the issues have had super obvious solutions, such as plugged burners and forgotten paper insulators. I'm getting real tired of kerosene fumes causing my eyes to burn, and I've spent all of my mad money having the furnace guy come out the first time.

When the propane guys came out, to pressure test the system, it was holding 9 inches of water. So, I'm guessing I'm a little low on the pressure, but will 2" makes that much of a difference?

 

[brewchief]

You need a manometer to check inlet gas pressure both with nothing running and then with the pilot and then main burners. If the inlet pressure stays at or above 11" then you should be ok, if not you have a gas supply problem.

If the supply is good then check the outlet pressure to the burner mainifold, it should be 10" when running.

There is an allen plug at each side of the gas valve that can be removed the check the pressure, pressure is adjusted under the slotted cap, remove it and use a screwdriver to adjust it.

Here's a simple water manometer.

https://www.amazon.com/dp/B00D38K39Y/?tag=atomicindus08-20

 

[sublime68charger]

I have no practical advice for you but to just say good luck and to keep plugging away at it!

Or bite the bullet and have the furnace guy back out to get it all running correctly!

There are probably lots of tricks of the trade that those people know.

How much of your time are you wasting n this when you have other things you could be doing?

I'm a big diy type but somethings just pay and get it done correct and move on.

Just my thoughts

Good luck!