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IECC 2018

  • 1.  IECC 2018

    Posted 08-13-2019 12:11
    I can't find an definitive answer to the issue described below in any other posts so I have started this new one hoping to get clarification.  Note that this derives from receiving a comment from an inspector (Illinois) that an aquastat is not an acceptable means for controlling the recirculation pump.
    I disagree with him but admit I am confused by the Code.  So I am looking for some help.
    Does the 2015 or 2018 IECC allow an aquastat as the only method of activating the circulating pump?  If not, what is allowed?  IECC uses the words "identification of a demand for hot water within the occupancy".  What identifies the demand?  Is demand only when it is actually needed? I have seen reference to providing a switch at the fixture to activate the pump.  But if that is acceptable then wouldn't an aquastat also be acceptable, since when the aquastat senses the set temperature it then "demands" hot water.

    Additionally, IECC states the pump must be shut down when there is no demand for hot water. Based on that, unless an aquastat is an acceptable form of demand, what is the point in having a recirculating system if it only works when there is a "demand" and what would be the point in limiting the run of pipe to the fixture as is also required by IECC?
    I have seen in another post that OSHA states recirculation pumps should run continuously, how can that meet the IECC's on demand requirements?

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    Tom Wilson
    Larson & Darby
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  • 2.  RE: IECC 2018

    Posted 08-14-2019 08:16
    Since we can't seem to get the electricity-conserving code officials in the same room as the water-conserving people, we do have some conflicting codes.  (Never mind the looming code threat of Legionella mitigation combined with anti-scald requirements)
    Our 'solution' (and I use that term lightly) is to show a disconnect beside the aquastat.  Redundant, I know. but the Energy Code in my state requires it.
    Lately I've been specifying a pump with ECM and integral temperature controls and scheduling. Haven't yet had a comment from the plans reviewers.
    Any B&G reps here who'd like to chime in?

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    Victoria Johnson
    Plumbing Engineer
    Bass, Nixon & Kennedy Engineers
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  • 3.  RE: IECC 2018

    Posted 08-14-2019 09:49
    What is required to sense demand is a flow switch in the cold water feed to the water heater plant.  This would open a contact in the recirculation pump circuit to de-energize the pump.  The thought is if there is demand, there is no need for the recirculation system to be operating, which I don't agree with.

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    Alan Worgo
    Watts Architecture and Engineering
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