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Thermostat anticipator setting confusion/Short Cycling


I am a bit confused when it comes to setting the thermostat anticipator. The boiler seems to be cycling quite often, so thought I would verify the thermostat anticipator(s) are set properly. Basically- the thermostat calls for heat, the boiler fires up, it typically will hit the 190 temp, and get shutdown by the Hydrostat. Then once it levels off, if room is still calling for heat, it fires back up again. Rinse, repeat. I asked the guy that installed the unit about it and he ensures me that these new boilers run more often because they heat less water, so it is normal behavior. But something seems off to me.

Any help/guidance would be greatly appreciated. I am confused by the thermostat instructions to set the heat anticipator to match the main control of the system. Would the main control be considered the zone valves (.32 Amps), or the Hydrostat connected to the boiler (instructions say to set thermostat Heat Anticipator to .2)...

Here are other specifics-

-3,000 Sq. Foot home
-140,000 BTU Pure Pro Boiler (Oil)
-Reillo Burner
-Hydrostat 3250 Plus
-4 Zone house
-Honeywell T87F Thermostats

Thanks in advance.


  • Solid_Fuel_Man
    Solid_Fuel_Man Member Posts: 2,456
    The 140,000 btus of oil boiler is most likely 5x the size it needs to be....

    What type of radiation and how much is in this zone?

    You can only dissipate so much heat, and with 140,000 btu/hr input the burner will cycle. Your installer is partially correct in that the boiler has less mass than your 9ld one (likely) so it cycles more often. Was a heatloss ov your home done? Was a radiation survey done?
    Serving Northern Maine HVAC & Controls. I burn wood, it smells good!
  • Jamie Hall
    Jamie Hall Member Posts: 18,953
    Didn't we look at this once before? It's not the thermostat. If the boiler is bouncing off its high limit, it's a mismatch between the boiler and the available radiation, with the boiler much too big -- as @Solid_Fuel_Man said.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    EBEBRATT-Ed Member Posts: 12,010
    Likley an oversized boiler.

    As far as heat anticipation goes it goes by what the thermostat is connected to. If it goes to a relay use the relay coil amps. If it goes to the HYdrostat its the hydrostat amps, zone valve zone valve amps