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  1. #1
    Join Date
    Dec 2009
    Posts
    2

    Default circulator pump control

    Was wondering if there exists a way to maintain ambient home heating temperature by either extending or independantly controlling the operation of the circulator pump. Have briefly looked into the Tekmar product line and not sure if this is already accomplished somehow with any of their units.

    Came to this realization one time when I had to temporarily bypass a faulty relay control board and noticed that with the circulator pump running more often the house heated more evenly and throughly.

  2. #2
    Join Date
    Feb 2008
    Posts
    554

    Default specificRe: circulator pump control

    oldbklyn:

    A lot of this would have to depend on the specific hot water system you have now, as well as your location, and several other factors.

    Constant circulation can be easily done on any HW system by simply making simple adjustments on the aquastat (usually a gray box 4" X 5" attached to the center of the boiler)---unscrew the cover & make a note of the settings by making a drawing of the innards on a piece of paper.

    There is usually a low limit, and a high limit---the low limit should always be 20 degrees lower than the high limit.

    Standard setting for the high limit is usually 180 degrees, or sometimes 200 degrees----standard setting for the low limit is 20 degrees below this, or 160 degrees---there is also a differential which should not be touched.

    If you set the low limit to 140 degrees and the hi limit to 160 degrees, you will get much longer circulation cycles and this will tend to "spread out" the ambience of the heat produced---but a lot will depend on the type & size of the convectors (radiators, baseboard, radiant, etc.) you are using---and if you have a sudden cold snap, you may well feel uncomfortably cold until the system can "catch up" with the heat loss in colder weather.

    People who live in moderate climates, or try this in early fall or early spring, can usually do well with this type of "constant circulation"---the reset devices sold by Tekmar & others try to do essentially the same job of controlling the boiler water temperature by comparing a boiler water sensor with an outside temp sensor and adjusting the boiler water temp accordingly.

    Constant circulation is widely used in commercial HW installs where there are different size radiators, or underfloor radiant tubing that would otherwise produce an uneven heating response in specific areas of the building.

    If you live in Brooklyn, the brunt of the heating season in December,January & Feb. is probably not a good time to try constant circulation, unless you have a small area to heat---most boilers and associated convectors are designed to operate at 180 degree boiler water temp to adequately heat the space intended.


    Regarding convectors, there's a certain amount of math that has to be done to calculate how much heat each room is losing in BTUs/hour to the outside (heat loss calculation (below) for each room), as well as the heat output of the room's baseboard, or radiators (baseboard heat output = 560 btu/hr/ft @ 180 degrees water temp)(radiators = vary-Google "calculating radiator heat output")---the heat output of a room's baseboard/rads has to equal or exceed the room's heat loss.

    Let us know how you make out.

    Also Google "constant circulation" hydronic heat ---for sites that cover this topic.

    http://www.bgmsupply.com/calculateheatloss.asp
    Last edited by NashuaTech; 12-02-2009 at 11:29 PM.

  3. #3
    Join Date
    Dec 2009
    Posts
    2

    Default Re: circulator pump control

    Located in Westchester now. 2 floor Cape with exposed pipes in garage. Semi finished basement. Changed settings to 180-160. They were set at 190-150. Second floor not as warm now though but main floor more comfortable. May try adjusting settings a bit to see how it affects second floor.

    Thanks.

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