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Central Boiler control when Thermostats and Zone Valves are within units in Multifamily?

5_degrees
5_degrees Member Posts: 2
in Thermostats and Controls
Hello all,

There is an existing 8 unit Multifamily building with a central boiler. Boiler pump is running 24/7/365 in primary loop. Secondary pump is running 24/7/365 and DHW is a sidearm with a tankstat that operates the DHW pump. Thermostats are tied directly to zone valves within the units and their is no homerun wiring back to the boiler room. We are replacing boiler (with mod/con), DHW tank and pumps. Existing boiler cycles like crazy between 140- 180 every 2-3 minutes.

What is most efficient way to control the boiler and pumps in this configuration? Does anyone know of an ECM pump that has a 0-10 Output to help control the boiler? Anythoughts on this would be appreciated.

Thanks,

Comments

  • SWEI
    SWEI Member Posts: 7,356
    You might at the Grundfos MAGNA 3. I'm not 100% sure what all it can do, but there is more flexibility there than I have seen in any other pump.
    5_degrees
  • wogpa67
    wogpa67 Member Posts: 238
    edited May 2015
    A Tekmar 263 should be able to handle all your needs. You may need a relay or two. The Magna 3 circs are awesome.

    Why are you only putting in one boiler? I like to do two for redundancy. Plus if you get a big domestic draw they handle it.
    5_degrees
  • ChrisL
    ChrisL Member Posts: 121
    I would have the boiler and pumps be controlled by the coldest apartment, with that apartment having a minimum temp setting of 70 or so. That way the water in the loop only has to be circulated and up to temp when needed, rather than maintaining temp at all times. Should minimize short cycling, standby losses, and pump energy draw. You could run a Honeywell wireless sensor to that apartment and avoid any additional wiring. Would also give you access to the thermostat via phone app, and email alerts if you have internet at the building.

    ChrisL
    5_degrees
  • wogpa67
    wogpa67 Member Posts: 238
    edited May 2015
    That sensor would end up in the closest dumpster.

    And the windows would still be wide opened. Not very conducive to the property owner.
  • gennady
    gennady Member Posts: 839
    Remove zones, install outdoor reset.
    Gennady Tsakh
    Absolute Mechanical Co. Inc.
  • ChrisL
    ChrisL Member Posts: 121
    Wogpa, your response is a bit sarcastic. I run this exact setup in some of my buildings with no issues. There has to be some level of economy, and running pumps and a boiler 24/7 is just not acceptable nowadays.

    ChrisL
  • 5_degrees
    5_degrees Member Posts: 2
    Thanks for the responses all. I think we will end up going with an ECM pump on the Secondary side and use an outdoor reset on the boiler. We may use a wireless thermostat to add a little bit more control in there.

    All great ideas!

    Thanks,

    DaveM

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