Taco circulator info/advice sought

Discussion in 'HVAC Heating & Cooling' started by Mainuh, Nov 25, 2007.

  1. Mainuh

    Mainuh Network Administrator

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    Network Administrator
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    Greetings all,

    I was tickled to find this forum after playing with my heating system several hours today. Thanks to Terry and moderators for hosting this!

    I have a small cape cod style home with a Taco 007 circ pump and (4) 24v zone valves which are Taco 571-2 (the transformer was upgraded when the 3rd and forth zones were added). Prior to this problem, the system has run fine for years, with the zone changes being in 2002. My most used zone is the 1st floor and that zone valve was original equipment with the house, so is about 14 years old. When the first floor is calling for heat the first couple or rooms get a little warmth in their radioators, but it hardly seems to make it all the way around. When I force the zone open it eventually warms all the way around and you can feel the return get warm (but never really hot).

    Thinking maybe the powerhead on the ZV was acting up, I swapped out that head with one of the others from which the zone was working fine. It still didn't circulate much until I hit the manual open lever.

    I did some seaches on here and didn't find anything directly matching, but have a couple questions based on what I read from the searches and what I found while experimenting today:

    1. I'm thinking the 571-2 base needs to be cut out and replaced. Is it common for these to be replaced or more than the powerhead?

    2. I read in one search here about air in the system being a complete show stopper. But if I can over ride with the manual open level and get some hot water flowing would that pretty much kill the air in the system theory, or should I still try flushing it? I did flush all 4 zones in September.

    3. when you use the manual open lever on the 571-2 does it open it as much as the powerhead?

    4. Anyone have any other thoughts on what could be the cause? I'm picking up a 571-2 replacement tomorrow, but would hate to cut into the system and have to sweat it all if there might be another reason for this behavior.

    Normally, I'd just call my heating guy and have him take a look, but got laid off a couple months ago and Christmas is approaching, so trying to figure this one out myself.

    Thanks!

    Don
     
  2. Rancher

    Rancher Guest

    Do you have a multimeter, you say the transformer got upgraded but it sounds like the valve is not opening all the way, can you get a voltage reading on it when it is open and closed.

    Rancher
     
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  4. GrumpyPlumber

    GrumpyPlumber Licensed Grump

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    Don, bleed the radiators.
    You should do this at the start of heating season every year.
    When you say radiators, I assume you mean old style stand-up cast iron steam radiators that were converted to hydronic.
    They are much taller than standard baseboard and flushing doesn't get all the air out, you have to bleed them from the radiator.
    I would almost wager money it's either air, corroded/clogged ZV, or the 14 year old circ needs a swap.
    Rancher makes a good point about the voltage tester, but if the zone is getting warm then it's likely getting the needed 24 volts, especially where the other zones are working.
     
  5. Mainuh

    Mainuh Network Administrator

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    I do have a decent Fluke multimeter, but kind of ruled that out since I took that powerhead and switched it with a known good one and the powerhead from the suspect zone worked fine when placed on a different zone.
     
  6. Mainuh

    Mainuh Network Administrator

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    Hi,

    thanks for the reply. Maybe I shouldn't have said radiator since it's actually baseboard heat. The only way to bleed it is to force the zone on, make sure the others are shut off, hook a garden hose to a spigot on the system and open the water inlet for the system (which I did in Sept).

    THe 14 yo circ works ok for the other 3 zones so I had kind of ruled that out. But I will flush that zone for air again before replacing the lower half of the ZV. But when I use the "open" level on the ZV to manually force it open, the zone does get warm, just seems to take longer than I think it should (12-15 mins for a small 24x36 cape).

    Don
     
  7. GrumpyPlumber

    GrumpyPlumber Licensed Grump

    Joined:
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    Occupation:
    Plumber, self employed
    Location:
    Licensed Grump
    Right Don, it isn't the circulator, it's doubtful it's the zone head itself, unless you tried the head from that zone on a different zone with the same electrical connection and it didn't work.
    Sounds to me like your initial guess is the correct answer, the valve itself.
     
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