Furnace help. Rusty Cuda?

beeper*71

beeper*71

This space for rent
Last fall I purchased a used Mueller Climatrol shop furnace for my garage. This thing is built like a tank with cast iron burners and heat exchanger and was probably built back in the 60's or 70's.
I have been pecking away at installing it and today it was ready to be fired up. It's set up to burn LP and once I finally got all the air purged from the lines I was able to get the pilot lit but I had to hold the button for nearly 5 minutes before it would remain lit.
Once the pilot was going on it's own I turned the controller valve on and flipped on the power and baby we got heat! :giggedy:

Well at least for awhile anyway. :( When the garage warmed up and the thermostat kicked off that was it, the pilot light had gone out and shut it down...damn. I relit the pilot and after another long period of time it stayed lit only to go out again as soon as I turned on the valve. Tried again and it stayed on once the valve was turned on only to go out again soon as I turned on the power. After that several attempts to re-light the pilot failed as it would go out as soon as the button was released and I finally gave up.

The fella I bought it from said he had the controller checked over by a service professional and it was good to go but he never got around to installing the furnace as his plans had changed so he put it up for sale.The controller looks as if it might be newer than the furnace itself.

It seems to me like the controller is not recognizing the pilot light. Could the probe that is exposed to the pilot flame be bad? Looks like it's been there since day one as the fitting holding it in is very much rusted and the tip of the probe looks a little melted.
Am I on the right track here or is the supposedly good controller the problem?

Any help would be appreciated.:)
 
sounds to me like the pilot is bad. It should only take 30 seconds or so of holding the button for the pilot to stay lit. Try removing all the wires from the gas valve except the pilot wires and try lighting the pilot if it won't stay lit the pilot is bad.
 
Pilot wires? Only two small wires on this controller that lead to the transformer which recieves the signal from the thermostat to open the valve.
Pilot light is lit and is supposed to remain so without any power to the unit.
 
Does the pilot have 2 wires that run up to the gas valve? or is it a small tube? Do you have a wiring diagram for the unit. Is this a standing pilot unit or does the pilot only light when it calls for heat?
 
Pilot has a small feed tube and stays lit all the time. A copper(?) probe is exposed to the flame and has a very small copper line or tube that connects to the controller to let the controller know a flame is present.

It acts like the controller cannot sense the flame and thereby shuts itself down.
 
Found this during a web search. I learned sumthin, it's a standing pilot system.

If you have problems with the pilot won't stay lit after you release the button or knob then replace the thermocouple. If you still can't get the flame to stay try another thermocouple then replace the gas valve (sorry there is nothing else that can be done).


This is probably what I need then, a thermocouple.....or probe thingy. :D


tcouple.jpg
 
beeper*71 said:
Found this during a web search. I learned sumthin, it's a standing pilot system.

If you have problems with the pilot won't stay lit after you release the button or knob then replace the thermocouple. If you still can't get the flame to stay try another thermocouple then replace the gas valve (sorry there is nothing else that can be done).


This is probably what I need then, a thermocouple.....or probe thingy. :D


tcouple.jpg
Click to expand...



correct- thermopile is weak!!!!! when it is working correctly is puts out about 200 millivolts to keep the gas valve open!!!!
 
beeper*71 said:
Found this during a strip search...

If you have problems with the pilot and he won't stay awake after your release, try again (sorry there is nothing else that can be done).


This is probably what I need then, a probing thingy. :D
Click to expand...

DUDE!!!!
This from YOU?
 
Ummm yeah, thermocouple most likely and the cheapest part you can buy for it prolly.
Heated garage be da' bomb. :)
 
uh....this might help! :shifty:



You know that it would be untrue
You know that I would be a liar
If I was to say to you
Girl, we couldn't get much higher
Come on baby, light my fire
Come on baby, light my fire
Try to set the night on fire
The time to hesitate is through
No time to wallow in the mire
Try now we can only lose
And our love become a funeral pyre
Come on baby, light my fire
Come on baby, light my fire
Try to set the night on fire, yeah
The time to hesitate is through
No time to wallow in the mire
Try now we can only lose
And our love become a funeral pyre
Come on baby, light my fire
Come on baby, light my fire
Try to set the night on fire, yeah
You know that it would be untrue
You know that I would be a liar
If I was to say to you
Girl, we couldn't get much higher
Come on baby, light my fire
Come on baby, light my fire
Try to set the night on fire
Try to set the night on fire
Try to set the night on fire
Try to set the night on fire
 
"Ground Control to Major beeper*71
Commencing countdown engines on....."

Dude, get someone to come in and do the final set up and firing of the furnace. A few dollars spent now could save you thousands later in the long run and maybe even your car, property and life!

LP is nothing to screw around with, especially if you are not qualified in installation and repair. [smilie=2:
 
I was trying to find how you could test the thermocouple I haven't done one in years but if its cheap enough just replace it. LP can be dangerous just make sure you clean all the orfices before you try to fire it up. Use soapy water to check all your gas connections for leaks. Lighting yourself on fire isn't fun (don't ask me how I know)
 
Sorry I'm late, but your on the right track, thermocouple first, also check to see that it is right in the little pilot light not off to one side, sometimes a little spider or dirt get on the flange & the flame is distorted. DO NOT stay in front of the furnace when you start it!
Flash back's a bitch !;) Rich.
 
Idiots.
CLEARLY the flux capacitor is out, gimme a break......Scotty always knew, how could you not? BTW....Scotty was from Sarnia. :D
 
Definitely the thermocouple . If you can find a friend with a manometer, check your gas pressure on both sides of the gas valve it will probably need to be somewhere in the area of 10" W.C. the data plate should tell you exactly. You will want it 1" higher on the supply side than the on the manifold side. If that sounds greek to you lemme 'splain. The supply side is just that, the side where the LP comes in. The manifold side is the burner side. (these sides refer th the test ports on the combination gas valve. The ( combi valve)combi has pilot and main flame regulators built into it .
One other thing to check... Be sure not to over tighten the thermocouple into the valve, as that will cause premature failure. Just be sure it is snug. You can pick up a thermocouple at most any home improvement or hardware store,As long as the tube is long enough and the mount is the same, they are fairly generic.. Just make sure you don't get a thermopile if you need a thermocouple. Your pic is of a thermocouple, most thermopiles are wired, and they are fatter than a thermocouple because they are nothing more than a series of thermocouples in one housing.
 
greg340 "GREGGLES" said:
Use soapy water to check all your gas connections for leaks.
Click to expand...



Yup did that, I used plenty of pipe dope putting it all together. I have a brother that sells and services propane and propane related accessories who gave me some helpfull pointers...we call him Hank Hill when discussing LP. :D The furnace worked fine once it was lit, I was a tad nervous getting it going and had an extinguisher at the ready. ;)

Getting the old thermocouple out is going to be a bitch as the threaded collar holding it in place is VERY rusted and not real easy to get at. Going to soak it down with penentrating oil and hope for the best.:helpme:

Hey Rusty, the flame is off to the side a bit but still touching the thermocouple, pilot flame is nice and strong though and certainly gets the thermocouple nice and hot.
 
Here's my crayolla version, thermocouple should be emersed in flame, both flames should be fairly equal, a little off could mean the difference, it's more than likley a weak thermocouple, most fittings are brass so the rust will just keep you from getting to it(mounting screws etc) but it should come out of the housing fairly easily. Rich.
 

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