Atwood heater low voltage

[Robojeeper53]

The Atwood furnace in my 98 Grandby has intermittent starts? Removed burner and spark assembly and looks great. One solution was install “dc to dc voltage converter” to maintain 12 volts if battery was on lower side. Battery will show 12.2 but not sure if furnace at board is reading a lower voltage. Has anyone eliminated an issue by using voltage converter?

 

[Vic Harder]

12.2 is already pretty low. A lead acid battery rests at 12.7 fully charged, 12.2 is equivalent to about 50% (no loads, no charging, at rest for an hour). Your heater will have difficulty at that low a voltage.

 

[Robojeeper53]

Exactly the issue. It was 30 degrees 2am and no generator. Was hoping a constant voltage would help furnace board be able to work better. When plugged in at home no issues but was 65 degrees. Anyone have any other ideas what it may be? The 2 voltage converters I was looking at come in 8 to 30 volt dc input and 12v or 13.8 dc output. Any issue with 13.8 out it says furnace is 12v. But that is what voltage is when charging? Anyway any input? Thanks

 

[Vic Harder]

Older trucks will easily put out 14+V while charging. 13.8 is a good number. 12v is lower than what you are getting now, so, no, 12V won't work.

Another option is the sail switch or excessive dust/debris preventing air-flow. Since your Grandby is a 98, you are unlikely to have the issue newer Atwood's do, with air restrictions caused by the output hose/cover plate blocking part of the air-flow.

I'd look at it as a partial "early warning system". At 12.2V you should stop using your battery anyway, as it is heading into the less than 50% SOC are where you are degrading the battery (especially if it can freeze).