The furnace will not turns on at "ON' mode. After some reading, I thought it would be the pilot light that has gone out. I re-lighted the pilot light to see blue-red flame, but the furnace will turn off AGAIN after 3-4 hrs. Replaced a new Honeywell non-programmable thermostat today with the following wirings:

Red wire to R
Black wire to Rc
Green wire to G
White wire to W
And
ORANGE WIRE TO Y!

From Honeywell's manual, it says not to connect any wire to O ( does O stands for orange?)
Is my wiring diagram correct from connecting the orange wire to Y?

The furnace would not operate when the fan is set to 'AUTO' mode for heat and cool. This is an ongoing problem and since we use A/C seldom during the summer, the problem is never look after. Any helps are great.

Regards,

Eric

Eric,
You may have compounded your problem by adding a new stat. A five wire stat is a little rare but there are several out there. The colors you used could be correct but you need to know how those same colored wires are connected to the control board in the furnace. Follow the wire back inside the furnace and check to see if the connections are identical to the new stat. the control board and the stat should have the same abbreviations: G,W, Y etc... If they are a perfit match them you still have your original problem and probably need to call a HVAC guy for a safe replair.
Bob

I have a 4 wire themostat (its actually 5 terminal, but the Rh and Rc terminals are shorted).

So Red goes to Rh&Rc
White goes to W
Green goes to G
Yellow goes to Y


But this has nothing to do with furance turning off... I'm sure there are other guys who will be bale to help you, sorry!