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Hot water circulation

My oil fired hot water baseboard system has a White Rogers Combination Control (remanufactured by Sid Harvey's) It seems to start the boiler OK (although it seems to turn on and off alot) but the water circulation pump seems to be running constant. Is this normal? This system is old the controler uses relay and gaps. I did install a solid state thermostat and set back to run at a lower temp while I'm at work or sleeping.

Thank you!


  • Michal
    Michal Member Posts: 213
    boiler cycling

    I am not too familiar with that control, but I will tell you that it seems to be operating normally, other relays operate the same way. What is happening is that the thermostat calls for heat turning on the pump and boiler. The circulator runs constantly pumping water. Now the Aquastat part of the boiler control is what is turning the boiler on and off. What is happening is that as the circulator runs, the boiler is able to raise the water temperature to the high limit setting and thus it shuts off the burner. Now the circulator keeps running cause it still calls for heat, so as the water pumps, it cools down. And then it reaches the low limit setting turning the boiler on again. This is Normal. There are other comtrols that Honeywell makes which will cycle the pump on and off while keeping the burner on constantly. But all in all, it seems to operate fine
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