View single post by hvacdrd
 Posted: Tue Dec 5th, 2006 04:43 am
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Joined: Wed Aug 16th, 2006
Location: Michigan USA
Posts: 1186
If pressure switch contacts are going from 24VAC to 0VAC then the switch is closing. I'm a little confused though. I thought we had a fault code '3' meaning pressure switch failed to close.

Am I reading correctly that the ignitor is glowing? Gas valve opens but does not ignite? Normal sequence is 1-combustion blower starts, 2-pressure switch closes, 3-ignitor warm up 17 seconds (50A55 Control),4- trial for ignition 3-5 seconds, 5-burner lights. Where are we in this sequence? Do you have a glowing ignitor when you hear the gas valve click?

It would be OK to remove the burner access cover to observe the burners during startup.

Ignitor resistance at 70-75F should be 50-400 ohms (usually around 100) - Amp draw is 4-5

Last edited on Tue Dec 5th, 2006 05:01 am by hvacdrd

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