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Plenum thermostat replacement or adjustment

Big Ed_4
Big Ed_4 Member Posts: 2,818
Sounds like either it's under fired , fan set too high or it's not baffeled. Is the Stack temp 400- 500 ? Fan temp set to 160 ? Firing rate 80% of maximum ?Low CO2?

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  • Andrew Rudin
    Andrew Rudin Member Posts: 29
    Plenum thermostat replacement or adjustment

    I am working with a 1,900 square foot residence with an oil-fired 0.85 GPH warm air furnace. I was able to start the burner, do a combustion test, and still have five minutes to spare before the plenum fan kicked in. That means the oil burner had maybe ten minutes to pump 560F air up the stack. The home uses above average oil per square foot per year. Does anyone know how much the plenum thermostat would contribute to wasting this heat?
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