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constant circulation

dds730 Member Posts: 1
I have recently moved into a house with a 4 zone hot water monoflo system with cast iron baseboard and a 60's vintage Burnham boiler. I am putting in a 96% boiler and would like to have constant circulation with outdoor reset. Is this possible with 4 zones? Thanks


  • SWEI
    SWEI Member Posts: 7,356
    if you have zone valves

    your thermostats will become high limit controllers.  This is very useful when you have external heat gains (wood stove, solar gain, etc.) which affect part of the space.  They can also be used to turn down the temp in an unoccupied zone.  It will likely take several hours to recover -- if you have guests coming you should raise the temp about a day before they arrive.   You do not want to use them for day to day temperature control.

    When the new system is first installed, crank them all up to maximum.  Make adjustments to the reset curve (in the boiler controls) and adjust valves on radiators or supply lines until you have even heat throughout the house across a range of outdoor conditions.  After this is done, set them 2-3F above the desired space temp and all should be well.  If you fire up the wood stove or have a sunny day, they will prevent overheating.

    Install an ECM circulator with that new boiler.  It will change its speed as zone valves open and close and generally make the system happier.  It will also cut your electrical consumption quite a bit.
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