bryant furnace will not light

somany?'s

My 1983 model bryant furnace will not light. The inducer motor runs, have 25v to brown wire on gas valve, nothing to any of the others. nothing to 3 wires on ignitor. have had main control board replaced by service tech (whole lotta help that did), I replaced the inducer board, the relay on it was charred beyond cleaning and it seems that oxidation on the inducer board was causing the 3amp fuse on main control board to blow right away, cleaned up the oxidation with a toothbrush and that stopped the fuse blowing but still no power past the inducer board other than that brown wire. thats when i discovered the bad relay and replaced it. i have 25v to all three wires on the flow sensing switch. hope somebody can help me.

#CARRIERMAN

Hi somany?'s

The three wire pilot your furnace uses has a tendency of sticking. Take a voltage reading at the black ignitor box. The box should have a common and the green wire to the three wire pilot on it. If you have 24 volts at this point and you are not igniting the pilot you either have a ignitor box bad or a plugged pilot. If you don't have 24 volts, take a plastic handled screwdriver and tap the pilot assy. This will sometimes allow it to shift back to pilot. Let me know if this doesnt do it and we will go a little deeper into it.

Good luck
Rusty

somany?'s

Hi Rusty,
Thanks for the quick reply. I don't have anything at the green or blue wire on the black spark generator.

#CARRIERMAN

Hi somany?'s

Did you tap on the pilot burner? And if you did what happened.

Rusty

somany?'s

yes, i tapped on black box and gas valve took readings and still the same.

#CARRIERMAN

Hi somany?'s

Don't tap on the black box or the gas valve, I did not mean to get you confused. I am talking about the actual pilot burner. Follow the white,green and yellow wires into the burner compartment and tap on that piece. I also noticed that you changed the inducer board. There should have been a revision note in the box that tells you how to rewire for the upgrade, it has to do with a red wire that goes to the safety's. If it is not hooked up properly it will cause the same problem. Let me know.

Rusty

somany?'s

Rusty,
I followed the wiring directions to a tee. and will go try tapping on the pilot burner as you suggest. thanks so much

somany?'s

Rusty,
Tried what you suggested, still nothing. There's no reading at the three wire connector to the pilot burner.

mdshunk

Reading your later post of the whole scenario, and knowing that you've already done some changes at the component level on the board, I'd hazard to guess that you have not totally healed that board. Just a guess at this point, as I don't have a clear picture in my head yet of that particular model of furnace.

somany?'s

Hello mdshunk,
I'm not sure what you're thoughts are. As far as the boards go, both have been replaced ( using new control board not one with water marks) not hacked. The furance is a model 397haw048100. any input is greatly appreciated.
Thanks

#CARRIERMAN

Hi somany?'s

Sorry about leaving you hanging, I had to go to bed. Now back to your problem. Has this furnace been under water, judging by the post with mdshunk it has either been under water or has had a condensate leak. If that being the case, go the post Bryant Inducer Fan Runs Constantly by biglittledan. In this post you will find a link for the wiring harness for your furnace, the factory part # is 305764-701. Just type this into the search bar and it will pull it up for you. It sound like your wiring harness has been damaged, which is not uncommon for this furnace. Let me know if I can help further, or give mdshunk a holler if I can't help you.

Good luck
Rusty

somany?'s

Rusty,
You're a genuis, the metal connector to the yellow wire at the inducer board was half gone, but not from corrosion, it seems to have shorted or something. Replaced the the metal connector and now have 25v to the yellow wire @ pilot but fuse blows on control board. Disconnected pilot from harness and fuse doesn't blow. Tried disconnecting spark generator from pilot with pilot connected and fuse blows. Do you think that this trail might stop at the pilot asm, or what are the chances of it going all the way to gas valve. I'm trying to decide if we should just buy a new furnace or sink more money into this one. Again any input will be greatly appreciated!
Thank you

#CARRIERMAN

Hi somany?'s

There is a good possibility that the pilot assy has a short in it, but if this still has the essex valve on it, that is more likely to be your problem. The replacement gas valve for your furnace is a EF32CW183. The easiest way to determine would be to undo just the gas valve out of the circuit and leave everything else connected. If the fuse doesn't blow you know its the gas valve. Let me know if I can help further.

Good luck
Rusty

somany?'s

Rusty,
Hi again! I disconnected all wires connected to the gas valve. No blown fuse, I reconnected them 1@ a time, the only time the fuse blows is when the blue wire that runs from the inducer board to the gas valve x2(fuse only blows when one next to the brown wire is connected) to spark generator to control board is connected. I can see the spark and hear clicking. Any thoughts as what could be going on?
Many Thanks

#CARRIERMAN

Hi somany?'s

There is no question that the gas valve has a short in the holding coil. The part # for the replacement valve is in my previous response. Let me know if I can help further. Just on last question for you, does yours still have the Essex valve on it?.

Rusty