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Recirculation Pump

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Dan_15
Dan_15 Member Posts: 388
in THE MAIN WALL
Thanks all for your thoughts; insulation is defintely key--I will insist on that. I can probably get away with a simple pump with integrated flow check that doesnt have a timer because the R2107 has a recirc feature built in. Thanks.

Comments

  • Dan_15
    Dan_15 Member Posts: 388


    Would there be any negative aspects that I should consider regarding adding a DHW recirculation pump to my system? I have Buderus G215/4 with R2107 and outdoor reset and room sensor (constant circ). I want to be sure it will not be bad for the system.
    Thanks.
  • RoosterBoy
    RoosterBoy Member Posts: 459


    the recerc pump is made to work with the 2107 keep in mind it could cost more to heat your dhw if you let it run a few times per hour. but then again it may not cost that much more because when your run your hot water at the fouset that water that your taking out of the tank is being filled back up with cold water. so your recerc might cost a tiny bit more to run. maybe someone here can answer better i have the g115 with 2107 and lt160 with bfu and was thinking about putting on a recerc also because i hate waiting for hot water i don't use allot of hot water though just a few times a day.

    the problem with that is if i don't run the recerc enough then when i do need hotwater it wont be there. and if i run it to much then the water will be there when i need it but cost more to heat my dhw per day.this is why i have not taken a weekend to install it. i want to be cheap on my oil bills. ;-)


    thanks
  • Mike T., Swampeast MO
    Mike T., Swampeast MO Member Posts: 6,928


    Increased energy consumption--running the pump and greater heat loss from the pipes. Heat loss greatly increased if the recirculation loop is not insulated. Insulation should be considered a HIGH priority!

    Often advantageous to operate the pump via a timer. Electronic with battery backup and DST changeover is probably the best. Otherwise, electro-mechanical timers that continue to operate the clock through a short power outage would be preferred to simple timers (electronic or mechanical) that either loose programming or track of time with power outages.

    Gravity alone will operate many recirculation loops--nearly all if piping is considerate, e.g. no up-and-down "heat traps" in the piping. Dave Yates has a WONDERFUL article on the subject in PM Engineer (hope that's right).

    With the recirculation under constant or timed operation it takes VERY little flow volume--thus it usually takes a VERY small circulator unless the loop is EXTREMELY long. Oversizing the circulator not only wastes electricity, but can cause excessive wear to the piping--particularly after any joint where the tube was not perfectly reamed.
  • Brian_19
    Brian_19 Member Posts: 115
    Grundfos

    I don't know the exact model number but I like to use the Grunfos recirculator. It has a built in timer, auquastat, and check valve.

    To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"
  • Weezbo
    Weezbo Member Posts: 6,231
    Taco makes a great bronze body pump with timer...

    add a strap on stat set at 90F and you will probably save money by not wasting water down the drain waiting for it to become warm...

    or Done every day all day long, not to worry.
  • Brad White_9
    Brad White_9 Member Posts: 2,440
    All valid points

    from the others.

    I would add a little considered aspect also: The greatest waste of heat from hot water is in summer, not winter. Assuming the recirculated water is within the heated envelope it at least contributes something useful, insulated as it should be, of course.

    Some codes, here in MA at least, require recirculation when the furthest fixuture is over 50 feet I think it is, from the source.

    Another tip. I do like the Grundfos system by the way, Taco is also excellent. But locate it near the fixture not back at the heater. That way you are maintaining the setpoint at the fixture not the heater return. You are thereby only satisfying the supply line side, not the entire loop.

    And with the timer programmed to your hours of operation the usage is very small. Tiny pump, just a trickle.

    My $0.02-

    Brad
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