Atwood 7920-II ignition issue?

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supermanotorious

supermanotorious

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Joined
Jun 29, 2015
Posts
592
Location
Phoenix, AZ
After working the inverter project, I realized I hadn't really tested the heater in our new hauler. So being a chilly day in Phoenix, I fired it up, it started just fine and ran for awhile. It reached temperature and cut off. As the temperature dropped, it never came back on. I looked and see the red LED flashing once every 3 seconds. I disconnected the power allowing the circuits to reset, plugged it back in, fired right up. Any ideas?
 

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The 3 flashes (ignition lockout) merely means the burner failed to re-ignite on demand. Or at least the controller board couldn't determine if it re-lit. It then shuts off the gas valve to prevent an explosion and waits for you to investigate. You shouldn't need to remove power - just switch it off & on again and it should try a new ignition cycle. If there is an external wall thermostat, just turning the t-stat off and on again should do it.

So the question is why did it not re-ignite. Since it's a DSI type ignition, you probably have to observe it to see what happens, e.g. did it not spark at all, spark but not light, light off but quit immediately, etc.

Get the appropriate Atwood Furnace Service manual at http://bryantrv.com/docs.html#furnace
 
Right there in the photo, 1 flash every 3 seconds: air flow limit fault.

Check for loose wires on limit switches, spider webs or mouse nests in ductwork, etc.
 
Was there any resolution to this issue?

I have a similar problem but my blower comes on for about 30 sec and then stops with out the heat kicking in. The fault light blinking once every 3 sec is the same. Limit switch/Airflow problems.

Where is the limit switch located so i can check it?

Air flow is fine.

2014 Coachmen Freedom Express 21TQX
 
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