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-   -   Magic Chef Furnace Combustion and Blower motor control (https://www.askmehelpdesk.com/showthread.php?t=627890)

  • Jan 15, 2012, 09:51 AM
    ccpjim
    1 Attachment(s)
    Magic Chef Furnace Combustion and Blower motor control
    I have a Magic Chef furnace, model EG6E80DC16-3, that works fine, but I'm troubled with the fact that the combustion motor and blower motor start up together at the start of a heat cycle. The schematic shows that it is wired correctly, both are turned on by single DPST NO relay. The typical limit/fan switch is not the controlling switch to the blower like normal furnaces are wired. The limit switch does open the combustion motor and burner valve like it should, but the fan control switch is a NC switch, always. Even though the fan switch has a setting for low limit, typically 100 degrees, and there is a setting for fan on, typically 125 to 150 degrees, but the switch is a NC single pole.
    This operation bothers me because why would a blower motor kick in before there is even any heat developed in the chamber. I have attached the schematic for review.
  • Mar 22, 2014, 05:59 PM
    jbww
    Yes, when calling for heat relay R1 energizes closing contact 1 and 3 starting the blower. This seems to be the way it's supposed to work.
    If you pull wires 1 or 3 off the relay, the blower will stay off until the fan/limit switch kicks it on. I don't recommend doing that.

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