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-   -   Bryant 3 wire pilot won't hold (http://www.diychatroom.com/f17/bryant-3-wire-pilot-wont-hold-84398/)

janibre1 10-19-2010 10:32 PM

Bryant 3 wire pilot won't hold
 
I have a Bryant 376BAW036075 that the burners won't ignite. It is a 1989 vintage furnace. This is what is happening.

1. thermostat calls for heat
2. inducer motor comes on
3. ignitor starts to spark
4. pilot ignites and burns and then it extinguishes
5. ignitor sparks
6. pilot ignites and burns and then extinguishes
7. Main burner valve never opens

This sequence continues indefinetly. I have replaced the three wire pilot and the gas valve and also the inducer motor control board. Nothing I do changes the above sequence.

kenmac 10-19-2010 10:41 PM

sounds like it's not proving pilot flame. If it doesn't prove pilot. It won't open main valve & pilot will go out

janibre1 10-19-2010 10:47 PM

The pilot is proving, but the pilot won't hold and it extinguishes when the main burner valve is suppose to open. If it was just a matter of the pilot not proving why would the pilot go out if the call for heat was never broken?

kenmac 10-19-2010 10:51 PM

That's why the pilot goes out. Some of the older furnaces proved the pilot was lit by the ignitor/ spark rod. Do you have a seprate sensing rod ?

janibre1 10-19-2010 10:53 PM

No, there is not a seperate sensing rod.

kenmac 10-19-2010 10:56 PM

Ok, then it senses through the ignitor rod & it isn't proving pilot flame shutting down pilot gas. then, it will re-try, still doesn't sense pilot flame & shtus pilot gas off again. It will do this over & over

janibre1 10-19-2010 11:02 PM

I thought that it sensed the flame through a warp switch that is built into the pilot assembly. The only wire that goes to the electrode looks like a spark plug wire and it connects to the ignitor module.

kenmac 10-19-2010 11:07 PM

It does have a bi metal switch in the pilot . When it gets hot enough it makes up and applies 24v to the gv. but if it goes out b-4 it gets hot enough to make the connection it won't open the gv. It senses flame back through the plug wire. The sensor wire or the board is bad. You might try to clean the sensor or the wire where it connects to the board

janibre1 10-19-2010 11:13 PM

I see I didn't mention it before but a also tried to replace the ignitor board and it didn't help. I suppose that the electrode wire might be defective even though it passes a spark throught it. I can try a new one tomorrow.

kenmac 10-20-2010 07:56 AM

All you have to do is replace ignitor rod & wire & you have a new furnace.

at 21 yrs old . I would have replaced the furnace

janibre1 10-20-2010 01:37 PM

Poor people have poor ways. The customer say's they can't afford a new furnace otherwise it would have been a gonner.

kenmac 10-20-2010 01:43 PM

Quote:

Originally Posted by janibre1 (Post 520155)
Poor people have poor ways. The customer say's they can't afford a new furnace otherwise it would have been a gonner.


they have already spent alot of $ in parts alone. I would check the heat exchanger real close for cracks/ holes


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