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circulation pump modulation.

hub4 Member Posts: 1
HI, I have a heatlink system, statlink controls, The issue that I have, I guess I really don't know if it's an issue or not is that when my room temperature is close to the set point. The tstat calls for heat, the led on the zone actuator will illuminate. The circulate pump starts. The tstat does not call for heat long enough to actually open the zone value. The circulate pump runs for a short time, say a couple of minutes then shut off. Sometime later this repeats. Is this modulation normal ?



  • Terry O
    Terry O Member Posts: 67
    edited January 2013
    I am a little familiar with HeatLink....

    having sold them for probably 15yrs. Heatlink Statlink  thermostats and control modules are not conventional providing bang on-off control like a standard thermostat/zone valve controls. They utilize proportional integral temperature regulation therefore it is not uncommon for an actuator to never fully open. From T-stat literature - "Proportional plus Integral (PI) controlled temperature regulation. Proportional moves quickly to the desired setpoint and slows down when the desired setpoint is near. Integral compensates the proportional offset (overshoot) and stays close to the setpoint." For more info I would suggest contacting HeatLink.- google HeatLink Usa and go to "contact us" for your region.   Good luck.
    Terry O
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