# Gas Heating Lockout Code 21 on Bryant 383 LAV



## stanmerrell (Nov 11, 2012)

I have a Day and Night or Bryant 383LAV Upflow furnace AC combo. This is electronic ignition with natural gas. The AC has worked nicely all summer, but now that winter has come the furnace will not perform. When started the blower motor runs for about a minute, then the gas tries to light, then the unit shuts down displaying the 21 code which means gas heating lockout. Manual says to check for a stuck gas valve relay on control or a miswire or short to the gas valve wire. I had to replace the door switch on this furnace last year. I cleaned the flame sensor. Still no luck. The unit is probably original to the house 1991...Any advice would be appreciated.


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## yuri (Nov 29, 2008)

Does the igniter glow red hot? If not it may be burnt out.


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## stanmerrell (Nov 11, 2012)

*Igniter*

Hi Yuri,
Yes the igniter glows red hot. Not getting any gas though. Thank you!


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## yuri (Nov 29, 2008)

check to see if you are getting 24 volts AC across the 2 wires on the gas valve NOT to ground. That is a very uncommon code and that furnace is quite old and the circuit boards had failures from poor solder joints so it sounds like it may be a bad circuit board.


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## stanmerrell (Nov 11, 2012)

*24v*

Thanks Yuri,
I'm getting 24 volts across the two wires shown on top of the gas valve. The current does not stop or start when the furnace is cycling. It is always present to the valve. One of the wires is green and seems to connect to ground. The other is dark blue. 
http://s222.beta.photobucket.com/user/stanmerrell/media/SAM_0467.jpg.html
Thank you.


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## yuri (Nov 29, 2008)

After it locks out and gives you the code it must not have voltage at the valve. If it does then the relay is stuck ON at the board and the code is correct and you need a new board. The board does a self check B4 starting its cycle and if that relay is stuck then it locks out. At 21 yrs old those units have problems with cracked heat exchangers and I would not invest $$ in repairs. Ventor fan and pressure switch and valve will fail soon.


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## stanmerrell (Nov 11, 2012)

*Replacement*

Okay. Thanks Yuri. I'm going to call for a replacement quote. Thanks again for your help with this.


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## yuri (Nov 29, 2008)

Your photo album is wide open for the public to see, you can make pics private on there and I would not be using my name on the internet.:no:


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