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White Rodgers Thermostat 90 series 1F97-371

I have a steam system boiler with dual burners the type with rolls of burners attached to seperate gas valves, dual gas valves and I assume what may be dual high limit switches mounted on top of the boiler for each gas valve. I assume that who ever wired the boiler did everything right,also there is this White Rodgers Type 8A04-1 Fan Relay with N.O. and N.C. Contacts that is not wired in I guess becuase there is no Circulator system involved (correct me if I'M WRONG please), there is no DAMPER IN THE SYSTEM and of course there is a low water cutoff on one side of the boiler and what I believe to be a water- pressure valve on the other side of the boiler all wired in.
My problem is I have 2 wires coming out of one of the high limit switches that I don't know what terminals of this 90 series thermostat should they be wired to. I did wire these 2 wires directly to the secondary side of the Transformer just to see if the boiler would work. The igniter did come on and the pilot lit, but the gas valves didn't open. My main problem is where does these 2 wires go on the thermostat If so or does that relay have to be wired in. PLEASE CAN SOME ONE OUT THERE HELP ME. I'm attaching the wiring diagrams I got off WHITE RODGERS WEB SITE. Thanks alot signed CONFUSED.


  • carol_3
    carol_3 Member Posts: 397

    If your loose wires are the high limit, they aren't connected to the thermostat at all. On any stat, when you're doing simply heating-only, you use just 2 terminals. They are R, which wires to the transformer, and W which wires to the load--which is whatever device makes the heat. (then the other terminal of the transformer and the load are wired to each other, and this makes the complete thermostat circuit.)
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