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  1. #1
    Join Date
    Oct 2005
    Posts
    3

    Arrow

    I have a 3 zone, three thermostat, hot water gas baseboard system. One zone doesn't work. Thermostat seems ok , can see small arc when mercury makes contact.

    I read on internet that three zones each with own thermostat should mean I have three zone valves. I only see two ????? Where could third zone valve be ?

    Anyway, last night I tried using the manual lever on the suspected valve (taco 555-102 24v ) serving that zone and it made the heat work in that zone. Would that likely indicate that the power head of that Taco valve needs replacing ? There are three screws on the valve. I would guess the red and white be the power source 24v. What is third (top) wire for ? Ground ?

    How difficult is it to replace these. Someone told me they just twist off ? Do I have to shut system down at all, or do I just carefully remove and note position of wires, replace valve head and restore power ?

    Any help would be greatly appreciated....I'm pretty handy electrically and mechanically, just never had to mess with plumbing or heating at all.

    Thank You,,,

    JS

  2. #2
    Join Date
    Mar 2004
    Location
    SE Michigan
    Posts
    17,830
    Probably shouldnt start now.
    "Politicians are the lowest form of life on Earth. Liberal Democrats are the lowest form of politician"

    - General George S. Patton

  3. #3
    Join Date
    Oct 2005
    Posts
    3
    thanks alot

  4. #4
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,760
    You wouldn't be the first person that burnt out the transformer, and t stat.

    I'm sure your handy at electric, and mechanical things, its just that I,m not there to make sure you undestand what I mean, so I can't tell you how to do it.


    Good Luck...


    PS: this is not a DIY site.
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    How many times must one fix something before it is fixed?

  5. #5
    Join Date
    Sep 2004
    Posts
    654
    The power head appears bad, especially if green in color (signifies really old, new ones are gold colored). Have it replaced, you shouldn't do it.

  6. #6
    Join Date
    Apr 2002
    Posts
    1,606
    Terminal 1 & 2 only in some applications.
    Terminal #3 for some applications run back to gas valve or what ever type primary control being used.
    Boiler control set ups vary w i d e l y.
    "The Bitterness of poor quality remains long after the sweetness of low price is forgotten"

  7. #7
    Join Date
    Oct 2005
    Posts
    3
    thanks for all the replies...some people tell me, just note and disconnect the wires, twist the head off counterclockwise, and replace.

    Can't keep up with all the repairs lately and just thought if it was that easy, i'd try to save the $200 labor I'm anticpating.

    Thanks again for the advice.

    JS

  8. #8
    Join Date
    Nov 2005
    Posts
    2

    taco zone head

    Well I must agree with others you should have someone else replace the zone head but if your determined to try yourself first turn off power to boiler then check voltage at zone head. (with three zones there should be secondary transformer!!! If not that may be part of your problem. after turning power off. Term #1 (top)should be the wire comming back from thermostat. Term #2 is (middle) is combo secondary from trans and part of end switch. Term # 3 is end switch. If you try to remove zone head while energized you will mess it up as well as fry your trans . Recommend hireing a plumber or exp, hvac tech and learn from him. Good-luck

  9. #9
    Join Date
    Mar 2004
    Location
    CHICAGO SUBURBS
    Posts
    464
    Burn up your controll center and It'll cost more than 200$.
    Some people swear by me and some at me

  10. #10
    Join Date
    Sep 2004
    Posts
    654

    Re: taco zone head

    Originally posted by mphac
    ...if your determined to try yourself first turn off power to boiler then check voltage at zone head. (with three zones there should be secondary transformer!!!
    Actually, each Taco zone head consumes about 10 VA of power, most transformers put out 40 VA...so mathetically, then, a typical transformer can handle 4 zone heads. In actuality, I've seen 5 zones run off a 40 VA trans, and it works fine.....how many at the same time will be calling for heat anyways?

    Originally posted by mphac
    ...If you try to remove zone head while energized you will mess it up as well as fry your trans . Recommend hiring a plumber or exp hvac tech and learn from him. Good-luck
    Actually, I've changed many a Taco power head by FIRST removing the #1 terminal (24 volt power) then remove the rest of the terminals. By the time you finish taking terminals 2 and 3 off, the head is relaxed and safe to R&R. I consider a zone head changeout achievable by a competent HO.....Good luck.


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