Gas and Oil Home Heating Furnaces - Holly furnace won't light

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kqresq
12-18-07, 08:13 PM
I have a 40 year old Holly Gas furnace that will not light. The pilot burns great, thermocouple tested fine, limit switch is good, I have power to the gas valve and I jumpered the two wire t-stat. Still no burner ignition.
Gas valve bad?


Jay11J
12-18-07, 08:23 PM
If you did put a meter across the gas valve and you are reading 24 volts ac, then yes you have a bad gas valve.

Be sure your gas valve is turned to ON. I've seen this before where it was left in pilot.

kqresq
12-18-07, 08:49 PM
This is an odd Honeywell valve. There is no pilot mode. The pilot is fed from a manual double valve-one lever for the control valve, one lever for the pilot. The wiring and thermocouple go to the control valve and red push button like I've seen for pilot controls, but no pilot control knob.
Of course, the label fell off the control valve years ago so I have no clue what the model number is. Does Honeywell usually stamp a part number anywhere on the valve?


mbk3
12-18-07, 08:59 PM
Does the pilot tubing go directly to the pilot or thru the safety?
Also how did you test the thermocouple?

If memory serves me: Holly was equipped with a safety, valve & regulator. Most techs remove all and install a combination valve. One that has all three in one.

Jay11J
12-18-07, 09:03 PM
wow.. you really do have an oldie there!

THought about updating to a new high effencey furnace?

You'll have to get all new gas valve, and that pilot system you got will have to go away... I don't think that style is made anymore.. (unless someone can correct me on this)

mbk3
12-18-07, 09:07 PM
wow.. you really do have an oldie there!

THought about updating to a new high effencey furnace?

You'll have to get all new gas valve, and that pilot system you got will have to go away... I don't think that style is made anymore.. (unless someone can correct me on this)


"Pilot safety system" still available...expensive. probably an A-100 or equivilent.

kqresq
12-18-07, 09:16 PM
Yeah, this is the original furnace in a house built in 1965! Sadly, a new furnace is not financially feasible at this time. And it is in Las Vegas so it's not like there is a lot of demand.
I figured it would take an updated valve. As the furnace is only rated at 80,000btu I'm assuming almost any universal standing pilot valve that I can plumb in there will work.
Oh, I actually replaced the thermocouple even though I'm sure the old one is okay.