Gas heater not igniting main burner -- ideas?


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Old 02-06-10, 09:37 PM
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Gas heater not igniting main burner -- ideas?

I've got an A.O. Smith gas water heater, Model FPD-40 (I think they're called "Sealed Shot"). Has a blower mounted on top which vents to the outside, and electric ignition element.

Noticed that for the last few hours, the blower keeps coming on and after ~30 seconds, switches off. Did some poking around, and it appears that the relay that fires up the ignition element isn't firing. Looking at the wiring diagram on the front of the tank, I presume I have either an inlet or outlet vent blockage, causing a kill switch somewhere to trigger. Likely due to the massive snow storm that just dumped on me (DC area -- got between 20" to 30" of snow, with another 5"-6" possibly mid week next week).

Anyone think that is possibly the problem, or might I have another failure of a different kind, such as the thermocouple spontaneously deciding to go bad or gas solenoid dying? Wanted to get some opinion before I go spending another $200-$400 to have a plumber navigate the treacherous roads to come out here.

I've already tried various screwball ideas, such as tying 25' of CAT-5e network cable to my snow shovel, and launching it up onto the roof in a vain attempt to knock enough snow off to clear away the pipe. But that didn't work quite so well....Got the snow shovel caught behind one of the exhaust pipes, probably the one from the gas furnace. So, until I find another object to toss up there, I'm open to ideas....
 
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Old 02-07-10, 02:41 PM
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If your air intake or exaust is blocked there is a good chance that the unit is shutting down due to no ventilation. If you see snow near the discharge of the pipe thats a good place to look, sorry.
 
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Old 02-07-10, 03:18 PM
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Originally Posted by shacko
If your air intake or exaust is blocked there is a good chance that the unit is shutting down due to no ventilation. If you see snow near the discharge of the pipe thats a good place to look, sorry.
Yeah, I think that's what it is. It came on today, after I let the afternoon sun heat things up a bit. Now I just have to find an inventive way to dislodge the snow shovel from behind the pipe so I can clear my driveway...
 
 

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