Lennox G12 series furnace will not fire...

[aiannone]

Hello all. I am renting a condo from a nice guy who happens to be in Russia right now, so he can't help me. I have some basic experience with electrical wiring and thermostat install / replacement, but right now I am very stumped:

Lennox G12-03-82 series natural gas forced air furnace.

Combined heating & A/C system in multistory condominium.

The following terminals are present on the furnace: R G Y T W

R & G are hooked to the thermostat.

Y is hooked to the thermostat, but also cross-wired to another wire which goes who knows where.

W is not attached (!)

T is not hooked to thermostat (where would it go?!) but hooked to a wire which, again, goes who knows where.

When we arrived, the previsous tennants had pretty must knocked the old thermostat off the wall while moving, and bent the coil all up, so I sprung for a basic home depot digital thermostat. Old thermostat only had three wires hooked up (R G Y), and hooked the same up to the new thermostat.

Air Conditioning works fine (Blower blows and air is cold)

When heat is selected, the blower does not blow nor does the furnace fire up. The pilot light is lit and strong, and the gas cock is in the on position.

With W hooked to nothing, I can't see how the furnace would ever fire! And I have no idea what 'T' is for... Any ideas or suggestions on getting the heat to work? I'm tempted to disconnect the T like and hook up W to the thermostat, but I am loathe to touch things I do not fully understand.

Reagards and thanks in advance,
Anthony

[Senior Tech]

white to w but the unit should be checked out by a professional before attempting to use as it could have been unhooked to prevent a dangerous situation.
And what kind of landlord would leave the country and not leave some instruction as to who to contact in case of an emergency...

[t527ed]

do not change t wire it is going out to a/c unit for common.
please get someone who knows what they are doing to have a look. may be a big problem that w was disconnected.

[aiannone]

Hello again....
What do you mean by the T wire is the common for the A/C unit - you mean sense/power? That would, in fact, be important.

Re: W wrie, there is a four conductor cable going into the wall from the terminals on the furnace, and comes out by the thermostat. As far as I can tell the W terminal was never hooked to anything (eg there is no wire at all hooked to the W terminal) and there anre no spare conductors at all for it to even be hooked to. Any ideas how the heat could have ever worked in such a configuration? I get the feeling I will have to call someone but with the landlord in Russia and no ready way to contact him, I am kind of on my own re: whom to call and what to pay etc.

Thanks again,
Anthony

[t527ed]

call service co preferably lennox dealer, pay what he tells you to. unless unreasonable price, then call for second opinion.

[mavericknga]

call a professional. the money is well spent.and that way you will still be here tomorrow to enjoy the day, w wasn' hooked up for a reason,could be gas leak, flame roll out or numerous other problems.crbon monoxide is deadly

[Black Adder]

Tstat wiring seems to be for cooling only, unless somebody monkeyed with the furnace wiring there is no way in hell you are going to get heat without the white connected at the furnace and tstat. If you can't follow the wiring diagram on the furnace or it does not correspond to the existing low voltage wiring I am afraid you are going to need a tech to figure it out.