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Zone Valves or circulators

Robert O'Connor_3
Robert O'Connor_3 Member Posts: 272
in THE MAIN WALL
I am installing a new system with 4 zones (1 for the indirect). One contractor wants to use one circulator and 4 zone valves the other insists on 4 circulators. I already have 3 circulators and they are less than 5 yrs old. I really would like to know the pros and cons from some of you who do this for a living.. Thanks

Comments

  • Al Letellier
    Al Letellier Member Posts: 781
    ZV's or circs

    We almost always use circulators for this kind of application. Unless the zone valves are full port motorized ball valves, the head loss through the valve will decrease flow to the indirect. Most manufacturers say not to use zone valves for this reason. We also find more maintenance issues with zone valves.
    From a pro....go circulators!!!

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  • heatboy
    heatboy Member Posts: 1,468
    What kind of flows are required?

    Hi! My name's heatboy and I'm a recovering pumpaholic :-) My take would be that if the individual zones fall within a certain parameter (GPM & Delta P) as a group, I would opt for zone valves with a pressure by-pass. Indirect water heaters should have it's own pump, though. Pressure drops and GPM requiremnents always dictate the size of the indirect pump, which can be bigger than heating pumps depending on the indirect chosen.

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  • hr
    hr Member Posts: 6,106
    Mostly zone valves

    like heatboy, it depends on requirements. Going with a 1" ZV for the indirect will help flow rates. Lets face it at some point the drop is "the coil" Especially in tanks with 3/4" finned coils for their hxs.

    I've yet to see a pump designed to meet the load and pressure drop exactly for each zone, although the 3 speed Grundfos are nice for zone pumping.

    Zone pumps really should be adjusted with a flow setter, rarely does this happen on residential zones. As a result the pumps are running all over the curves. Drop outside of the "sweet spot" and you are probably running less than 20% efficiency on that circ. So from an electrical consumption viewpoint, ZVs win hands down.

    Either way will work fine, it's more of a personal preference type of choice.

    hot rod

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  • Big Ed
    Big Ed Member Posts: 1,117
    Service

    My vote would be..... circulators and proper size flow valves. My decision is based solely on being a 30 year service grunt ....
  • Floyd_5
    Floyd_5 Member Posts: 418
    I hate to disagree...

    with HB and HR, but I really can't see where a pump running at 20% eff. when it only pulls 7/10 of an amp to begin with is a problem. Also I think we see way more trouble posts here with zone valve problems than with circ. pumps.

    For me I want the redundancy of multiple pumps, if my customer calls on Fri. night @ 6 and I'm ready to go out with my wife, the last thing I want to do is say "sorry Honey"!!!!!
    With more than one pump they can still get some heat in the house and I can get to it Sat. morning after I have had a good dinner and my "reward" for being a good boy and keeping my end of the night up.....if you know what I mean.....

  • Steve Eayrs
    Steve Eayrs Member Posts: 424


    I go with zone valves mostly, w/ pumps quite often on the dhw zone.


    Not sure exactly why the east coast guys use pumps, and most of us out west use zone valves.


    The small difference in power draw can also make a big difference if you are on a electrical system off the main grid, or pay more for your power than most.


    No one can convince me that valves go out a lot more often than circs. Maybe a taco rep. can speak up and tell us which they sell the most of.....replacement circ cartridges, (for smaller pumps 007, etc.) or zone vlv heads. We have to replace a fair amount of the taco circ cartridges around here.


    Also..... whats the problem with having the customer manually open the zone vlv until the next morning?? Or close the ball vlv if the zone is stuck open?? Beats not having circulation at all on a zone, because the pump froze up.


    Steve
  • Floyd_5
    Floyd_5 Member Posts: 418
    You missed the whole point...

    if ya only got's one pump and that fails...don't make no difference what ya do with the zone valves, your still up the crick with out a paddle.......
  • jim f
    jim f Member Posts: 182
    situation??

    how about a system consisting of 4 zones. 3 1" zone valves supplying 3 air handlers at around say 80,000 btus at 180* water temp and a phase 3 tr-80 indirect wich requires an 1 1/4" supply and return. 2 out of three air handlers are in the attic (3 stories). dont you think you would need a fairly large gpm circulator to fufill max demand???. but wait!! if only one zone calls with this high gpm circulator, what will happen??
    i like individual circulators designed for each indivdual zone. and use max diameter piping to indirect with a high volocity circulator.
    jmho
    jim f.
  • steve_26
    steve_26 Member Posts: 82
    circs

    good point jim.
  • hr
    hr Member Posts: 6,106
    Jim

    That is exactly what HB and I refer to when we said, depends on the load and flow. If I can't make all the loads with speed three on a Grundfos 15-58, then multiple pumps certainly are the better choice.

    I wouldn't zone valve with high head pumps, it's time to split the load among several pumps.

    Floyd, yes that is a small, small power consumption. Multiple it by 6 or 8 or 12 which is not uncommon in a medium to large multi zoned radiant and soon you have more electrical consumption than fuel :)

    Ok, not quite! But 8- 78 watt circs to move 100- 150,000 BTU? Still seems over kill. Add to pumps the cost of iso- flange, pump relay, flow check, and assembly time and the cost is a bit higher.

    STILL, I'm not arguing one is best. Depends on what you like. Ford, Chevy :)

    hot rod

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  • jose
    jose Member Posts: 17
    Enough of the technical stuff

    Personally i prefer individual circs. and flow valves, onlt because if one fails, u dont loose all your heat and hot water.
    And i found on occassion where one circ. was piped with some zone valves, when all zones are calling for heat and one satisfies and closes, it bangs shut because the others ae still calling for heat.
  • eleft(retired)_3
    eleft(retired)_3 Member Posts: 33
    Z/V's

    HR has it correct about all the extra expensive hardware.

    I put ZV's on the return at the boiler, never heard any bang shut!

    al
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