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Electric Furnace Help

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  • 109A_5
    109A_5 Member Posts: 3,316

    Well…

    " Could be easily changed by putting in a two stage thermostat "

    Not without rewiring a bit, W2 when connected internally does not do much.

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    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
  • 109A_5
    109A_5 Member Posts: 3,316
    edited November 7

    Anyway back to troubleshooting. Divide and Conquer. Is it control or sequencers ? Figuring out which one it is gives you troubleshooting direction.

    To do so is relativity simple. Set up to measure the 24 VAC across the of the sequencers' heaters at the sequencers. Since your issue happens so seldomly I would connect to the heater terminals rather securely (you could use any unused heater terminals) and bring the wires out of the cabinet through the thermostat wire breach so you can get information without even touching the heater. Then connect a 24 VAC indicator of some sort, multimeter, dedicated AC voltmeter etc. So when it acts up you can see if the 24 VAC actually makes it to the sequencer heaters. No 24 VAC control issue, 24 VAC present and nothing else happening sequencer issue.

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    As an example: BocaTech Inc. BT3ACW30 Panel Meter, 0 - 30 AC Volt Meter. Inexpensive on eBay.

    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
  • 109A_5
    109A_5 Member Posts: 3,316

    Interesting the R side is grounded.

    image.png
    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
  • 109A_5
    109A_5 Member Posts: 3,316

    With all the crimped wire terminations and connections (Orange arrows and others in the control circuit) it would not surprise me if one was causing your issue, it does not take much to make a bad intermittent connection.

    image.png
    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
  • 109A_5
    109A_5 Member Posts: 3,316

    @EBEBRATT-Ed

    " But it looks like another wire is on the lower middle contact …can't see the color or trace it Just curious as I don't see it on the diagram. "

    Its the Red jumper (blue crimp on) between the NO and NC contacts. The lighter blue crimp on goes to the motor.

    image.png image.png
    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System

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