I have a Bryant 350mav furnace that won't ignite. It was working fine up until this afternoon, now there's no sign of any flame inside after the clicking (naturally on the coldest night of the year!). All the fans seem to work fine. Has the ignitor gone bad? If so, how do I check it?
http://www.gogeisel.com/geiselonline..._355MAV_OM.pdf
Verify that you have a code 14 or 34.
Reset power and observe the starting sequence. If the ignitor never glows after the inducer runs and you get a 14 or 34 error code you can ohm it out or visually inspect it for cracks.
The pictured ignitor runs @ 76 ohms when good. If the furnace is very new it will have a different ignitor (silicon nitride) and have a different ohm reading.
The LED is showing one short and four long--which I think is Code 14.
I admit I am a novice, so I am not sure where to look for the ignitor glow. Is it in one of the two windows where I used to see the blue flames (above the gas valve assembly)?
I have seen other pictures of the ignitor like the one you show, but can't find anything like it on my furnace.
Thanks so much, by the way, in how fast you responded. Everyone here is bundled up for the night!
DD
Okay. I located the ignitor over on the right side of my furnace. I replaced it with a new one (now that it's daylight and things are open!) I set the thermostat on 80, then reset the furnance with its on/off switch.
Fans worked again. Unfortunately, no flames or other appearance the new ignitor made a difference. The LED is solid until the clicking sound, then it goes to 3 short, 4 long, then after (I think) three clicks, the furnace stops the fans and goes to the Code 14.
The old ignitor has some white deposits on it but doesn't have any deep pits like shown in your photo.
Ideas?
Dave D.
When the thermostat calls for heat, the inducer motor should switch on and come up to speed. At that point the pressure switch should close. Then the ignitor should turn on and get white hot. Then the gas valve should turn on, allowing gas to light off the ignitor.
It sounds like the ignitor isn't lighting and the main burner gas valve isn't switching on. Despite that, the diagnostic lights you are getting is signaling that the burners failed to light.
That suggests that the ignition control module may not be operating properly, failing to turn on the ignitor and failing to turn on the gas valve.
Disconnect the ignitor at the plug and use a multimeter to see if 120 VAC is switched on after the inducer motor comes up to speed. Also check for 24 VAC across the gas valve to see if that is getting turned on. (And check to be sure that the manual and electric gas valves are turned to the on position).
If it turns out to be the controller board, about how much should those run? $250? $150? $10??
I just want to know when I call the parts store if they are in the ballpark or if I should look elsewhere.
I'd look for a Carrier/Day and Night/Bryant/Payne distributor and see if they will sell to you, or shop on line.
A furnace repair outfit will be buying from one of those outfits and adding a healthy markup.
Okay. Replaced the ignitor and the control board. Furnace took a much longer run-up time before igniting, but the burners came on and hot air is blowing!
Cost: $26.00 ignitor, $250.00 for the board.
I did see boards for 350MAV's online from $250 down to $100, but I could not be sure the cheaper ones were the correct replacement as there seems to be a variety of different boards in the system.
I am thinking that except for filters and a new fuse, the 350MAV only cost about $40.00 a year in maintenance--not bad.
Thanks for your help! It definitely reassured me I was on the right track with the board and not something like the gas valve or such.
Dave D.
One other item for others who install a new board:
The new controller board has waayy different timing than the old one. So don't be surprised if the furnace blower starts running 10-15 minutes before the ignitor kicks in. (My old one took just a minute before ignition.) This really threw me when the furnace kept running and running without ignition. (Egads! Is it broken again?? Nope--there goes the glow!)
Apparently, the new board works with a variety of furnaces and I guess has to make allowances for different configurations.
Originally Posted by ddoering
One other item for others who install a new board:
The new controller board has waayy different timing than the old one. So don't be surprised if the furnace blower starts running 10-15 minutes before the ignitor kicks in.
Actually, I would be surprised. I doubt very much that such a delay should be occurring.
I'd be especially suspicious that the pressure switch isn't closing reliably, allowing the ignitor to switch on as the next step. I's check that out, and read what the installation manual for the ignition control says about such timing.
Curiously, those ignition delays have now gone away. (Possibly the controller had to adjust to the new system?)
The furnace seems to be running fine--considering it is not gone about 10 degrees here for the last four days the unit is certainly getting a good shakedown.
Dave D.
No. Hope for the best, but it will probably be baaaaack!
No way, on that delay. I second the motion on the pressure switch not closing. It is currently marginal and the problem will be back, more than likely. Unless you coincidently had snow blocking the vent pipe, and it now melted.
That, in fact, is so common (during huge snow storms, with say drifting and or people shoveling/ banking snow against their house) that some honest reputable furnace companies will even mention about making sure the vent pipe is clear, over the phone, rather than drive out and charge a person for something like this, where no actual mechanical malfunction is involved.
Tags: bryant, 350mav, ignite, controller board, pressure switch, 10-15 minutes, 10-15 minutes before, 10-15 minutes before ignitor, 10-15 minutes before ignitor kicks, after inducer
