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Taco ZVC403 Issues - Bad zone valve?

tabeth
tabeth Member Posts: 10
in Gas Heating
I have a Taco ZVC403 and one zone is calling, but the valve is not open (see picture). There is one zone in the house that barely heats. I assume that the valve must be partially open and some warmth is potentially being transferred from other zones.

See the pics. The zone shown labeled 3 also seems to be pretty worn. The other curious thing is that all of the zone valves are hot when one zone is active. I'm not sure if that's what should be happening, or not, though.




I do have a new zone valve, including head ready to install, but don't want to install unless that's actually the issue as I'd have to turn the heat off for a while.

Comments

  • Big Ed_4
    Big Ed_4 Member Posts: 3,083
    If you have 24V to the zone valve and it does not open , you have a bad valve..

    There was an error rendering this rich post.

    HomerJSmith
  • HomerJSmith
    HomerJSmith Member Posts: 2,635
    edited January 2023
    You can check the input temp to the ZV and the output temp at the valve and the boiler output at the boiler gauge. The temps should be the same. I'm assuming that the ZV is on the output of the boiler and not the return. A higher boiler temp and lower input to the ZV indicates a valve that's not opening.

    I understand spending money on a part that's not broken is something one doesn't want to do. Switch power head with another ZV and see if that makes a difference.
    The problem still might be in the seat assembly itself.


    Dave H_2
  • SteveSan
    SteveSan Member Posts: 280
    On the Taco control, when a t-stat is calling you should have approximately 24v between 1-2 at the zone valve connections. Then, after 90 seconds or so, should have that same voltage between 1-3. If not, could be the actuator has failed. You can always switch a working actuator with the problem one to see if the issue follows or stays the same. Please give Taco Technical Services a call at 401-942-8000 just ask for Technical Services and you will be directed to one of our Techs. We are here Mon-Fri 8am-5PM EST.
    Dave H_2

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