Gas Furnace

Unknown

not getting the correct air/gas mixture with the door in place. How is this unit getting its air for combustion? Is this a sealed door on this unit?

Paul, P.C. Heating

Gas Furnace Help

Customer has a 1995 Hiel Gas Furnace. We replaced the gas valve. With louvered cover off, pilot lights then burner lights. We put the cover back on but the ignitor clicks but the pilot will not light.
We took the cover off and everything lights.
We put the cover upside down and everything still lights.
We put the cover on correctly and nothing will light.
Please help.
Thanks,
PC

Steve M_2

Adjust pilot

You probably just need to adjust the pilot and don't forget to check the manifold pressure.

oil-2-4-6-gas

Unknown

Take the pilot out and clean

the orifice and while you are at it clean the flame rod. Make sure the new gas valve is set for correct gas Natural or LP? Adjust the pilot to envelope the upper 1/2 to 3/8 of the sensing rod.

Did you replace with the exact same valve and why did you replace the valve to begin with?

Are you able to meaure microamps at all?

Timco

Cat I? Maybe the louvers are directing a draft onto the pilot & not allowing it to ignite? Was pilot changed & if so put back in exact place with exact same?

Tim

Paul, P.C. Heating

We went to the house on a no heat call. We took the furnace door off and checked for 24 volts to gas valve. Gas valve was getting 24 volts, but there was not any gas to pilot. Gas valve was the original valve so supply house cross referenced to another Honeywell gas valve. With door off, the pilot lights right up and then main burner lights. With furnace door on all you see is the spark from the ignitet. Thanks, P.C.

Glenn Harrison_2

Get a new pilot assembly

A lot of the Heil/Tempstar furnaces used the Honeywell Q345 Series Combo Spark/Sensor pilots in them with the straight spark Probe. Due to random situations like yours they switched to a Honeywell Q373 Series Pilot that has the electrode bent at a 90° into the pilot hood.

http://customer.honeywell.com/techlit/pdf/68-0000s/68-0094.pdf

Paul, P.C. Heating

gas furnace problem

6 year old Ducane gas furnace. Heating fan comes on intermittenly without a call for heat. It will run for approximately 2 minutes and then shut off. This could happen 2 or 3 times per hour or it may happen once per day. Ther is no set pattern. Could this be a bad P.C. board. Thanks, P.C.

Unknown

This can be caused

by a limit opening prematurely. Electronic Fan Timer boards are designed to bring on the fan if a limit or any part of a circuit shows an open switch or a loose wire.

Mitch_4

I had several like this

No Rhyme or reason. the inducer cycles over and over but there is no call for heat.

I had it in a church with 4 identical high efficiecny units, same stats, one did it the others were (and still are fine).

The diagnosis is
1- usually an electronic stat (the old H/W magic stats were the most common for this)
2- inducer cycling but NO CALL for heat. (look at the display)

3- Put your volt meter between R-W, turn on power and watch, you will likely read full voltage, then a sudden drop to 0 initiating the board to bring on the inducer.

Solution was an isolation relay R to the stat, W from stat to one side of relay coil, Other side of relay coil to C on the board.

The N.O. contacts of the relay are tied to R & W onthe board.

It seems to bee a weird feedback loop between the electronics..Most modern stats are better, but I still one or 2 a year. The relay adds a mechanical load to the circuit that is more than what is passed by the stat, stoppping the cycling.

Good luck.

Mitch

seabee570

ducane gas furnace

check the small tubing (hoses)going to inducer and proving switch.make sure there is no slack in the tubing.pull hoses of and check to see if any moisture is in there.Best to pull all hoses off and blow thru gently and then re-install