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You probably have the cycle rate set too slowly. Perhaps you followed the manufacurer's instructions and set the cycle rate for hydronics? That usually makes for 20 minute cycles (roughly 10 min on and 10 min off), known as 3 cycles (cph) per hour. Try setting the stat for "forced air" which simply gives you 5 or 6 cycles per hour, and means the heat probably will come on every 10 minutes or so (60minutes per hr divided by 6 cph = 10 min cycles). It will be closer to set point this way too. Manufacturers unfortunately are stuck on the idea that all hydronics systems are the old cast-iron radiators, which just ain't the case anymore. Electronic/programmable stats usually come out of the box set up for "forced air,"which is also just right for much modern hydronics. If you have a non-electronic mercury-bulb stat, let me know and I'll tell you how to set that.


  • johnz
    johnz Member Posts: 3

    Does anyone know of a good thermostat to use with hot water radiator systems? The programmable one I have seems to let the boiler run longer than necessary. The temperature in the house always rises by 1-2 degrees after the boiler stops. Thanks John
  • Tony_29
    Tony_29 Member Posts: 1
    amtrol smart control thermostat


    I have a boilermate 41 gallon classic, the 'smart control' started buzzing loudly, now no hot water. In doing some reserarch, I find there is a retrofit that changes the 'smart control' to a manual thermostat control. Any advice on which route (replace or retrofit) I should follow? I notice Amtrol just filed for chapter 11...

  • Rob_34
    Rob_34 Member Posts: 21


    So what do you do for the mercury type?


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