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  1. #1
    My old Taco 555-102 zone valve head shorted out the other day (upstairs zone) so I replaced it with the Taco 555-050RP. Taco says this is the correct replacement for 555. When I turn up the thermostat for this zone, the head gets warm, but the pipe to the baseboards is still cold (as well as the zone valve).

    My system has 2 zones, so to make sure there wasnt something wrong with the zone valve, I swapped heads with the zone that I know works. So now I have heat in the upstairs zone, but not the downstairs zone and the new head stills gets warm, but the pipe is cold.

    Did I just buy a bad head? Or is it not compatible? The zone valve head that works was replaced about 2 months ago by my boiler repair company. The one I bought looks almost identical to the one the company used (they are both the gold taco).


  2. #2
    Join Date
    Jan 2006
    are you sure you have it wired correctly? turn up
    t-stat check for voltage between terminals 1&2 if you have voltage with t-stat up and the power head is locked in (both screws) i would try another power head

    [Edited by ross973 on 01-26-2006 at 11:33 AM]

  3. #3
    Join Date
    Sep 2004
    Appears the replacement power head is no better than the one you took off. Put a new one on, if the old ones are green colored they are wayyyy old.

  4. #4
    The box of the head was a little suspect when I bought it (appeared to be open). But the sales person said it was fine. I just picked up a new one from a local supply store so I am going to try that tonight.

    To the previous poster, I am pretty sure that that wiring is correct because when I switched the known good and possible bad one (to check that the valves werent the problem) I did get heat in one zone, but not the zone with the "new" bad head.

  5. #5
    I installed the new head last night and it worked like a charm. So the one I got from Home Depot did not work.

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