Original message
| razorbacker
 |  "Bryant 383kav code 31 problem?"
, posted Fri 4 Apr 17:01  
I am having an intermittent problem with this furnace firing up and running. a code 31 flashes on the control board after every failure. Sometimes it will fire and operate properly but after the thermostat cycles several times the blower moter will continue to operate but the burner does not come on.
Sometimes, when the thermostat calls for heat, the draft inducer moter will pulse, sometines it will run 1 to 5 seconds, sometimes it will run 15 sec., I have observed everything between the pulse and running long enough for the burners to fire before the inducer shuts down and the furnace shuts down. I have observed the burners firing and shutting down and within 15 sec.s the inducer coming back on, the burners firing and the furnace operating properly. I have observed the code flash 31 for a about a minute, then the solid light come on and the furnace operate properly for one or more thermostat cycles.
The filter is clean. The limit switches (manual reset) do not need to be reset.
I ran the test, and the inducer, igniter, low speed and high speed blower ran for 30 secs each, this is correct according to the guide on the blower panel.
I have checked the flue vent and there are no obstructions. outside combustion air is available to the unit. The induction pressure/vacuum? switch checks 24 volts across the leads. the tube is not obstructed. Is there a way to check the pressure switch operation without changing it out? All electrical connections appear to be good.
Yesterday I turned the thermostat off, and jumpered from W to R terminals on the control board. the inducer ran for about 15 seconds and shut off. it pulsed 2 times about 30 secs apart. It came on and ran until the igniter started to glow and shut down. The error code flashed 31 then glowed solid and the furnace went through the start up sequence and began operating properly. I disconnected the jumper, waited until the blower stopped, turned the thermostat to heat, fan set to auto, ran the set temperature up and the furnace operated properly into the night. At which time the fan continued to run with burners off, inducer off, and the air temperature in the house 5 degrees below the set temperature. code 31 was flashing. Tell me it isn't the control board.
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Replies:
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| marchvac
| "Re(1):Bryant 383kav code 31 problem?" , posted Fri 4 Apr 18:30
Be careful sometimes you don't get a second chance
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| | marchvac
| "Re(2):Bryant 383kav code 31 problem?" , posted Fri 4 Apr 18:41
I hate to tell you its the board but most likely it is. If the connections on the ventor motor are tight and you are not getting a sold 110v to the motor with a call for heat. Jump the R and W at the furnace and make sure there is 110v to the motor. The last test is to bring 110 directly to the ventor motor and check the amperage is correct. Hope this helps.
Be careful sometimes you don't get a second chance
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| | razorbacker
| "Re(3):Bryant 383kav code 31 problem?" , posted Sat 5 Apr 08:59
Thanks marchvac. I did bring 110 to the inducer and it seemed to work ok. I didn't think to check the amperage. I was hoping there was a replacable relay that i couldn't find on the wiring diagram. Wishful thinking!
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