Lennox G8D2-82-3 Furnace

[John Martens]

Trying to trouble shoot a furnace for a friend before it gets too cold up here in Alberta...

It's a old Lennox G8D2-82-3. The furnace will not turn on no matter how high you turn the thermostat..I've taken a look at the thermocouple and it looks absolutely coated. I'm pretty sure this is the problem, however, the pilot light is on continuously so I can't get in there to clean it...I've cleaned the thermocouple on my furnace before but it is relatively new and only uses a glow igntion (or whatever it's called....sorry)...never one that has a pilot light on all the time...

Do I have to shut the gas off on the line manually and let the system cool down before I access the thermocouple or is there another way to get to it?

Thanks for the help!

[kdog]

If the thermocouple were bad, the pilot would go out - that's an old draft furnace like mine with a cast iron heat exchanger - parts inavailability will be the demise of these - if it's not coming on, see if someone hasn't shut off the switch (follow the powerwire), or a wire has come off the transformer from the thermostat (some thermostats have heat/cool switches inside them)

[John Martens]

Checked the power switch, still on. Checked the breaker box, no problem there and all the wires are secure. Is there something else that might be causing the problem?

Edited September 21, 2011 by John Martens

[jb8103]

If you're still out there, check for 24 VAC at the transformer.