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Has anyone on here had issues with Taco ZVC box buzzing and lights flashing but still working? I have never had one do this.


  • kcopp
    kcopp Member Posts: 4,431
    One time. Newer version. funny flicker on one on the displays.
  • STEVEusaPA
    STEVEusaPA Member Posts: 6,506
    What kind of thermostats?
  • SteveSan
    SteveSan Member Posts: 234
    What zones are the LED's "flashing". If you take the t-stat wires off the zone ( zones ) that are flashing and just jump the R-W of the zones does it still flash or are they solid? What type of t-stats and do they require a com wire?
  • Wellness
    Wellness Member Posts: 139
    If, after trying @SteveSan wiring troubleshooting without resolution, it may be a bad transformer or grounding issue.
  • rick in Alaska
    rick in Alaska Member Posts: 1,457
    You might need to use the resistors that comes with it if you are using power stealing thermostats. I can't remember what the resistant of them are, but I know they come with the newer ZVC control boxes. Some stats will cause this.
  • HomerJSmith
    HomerJSmith Member Posts: 2,441
    It may be that the two transformers are out of phase. Perhaps transformer A is somehow connected to transformer B thru some mis-wiring.
  • TJK500
    TJK500 Member Posts: 16
    Thanks for all of the help. I traced the issue to the a short in the main board near the master/slave switch.
    The thermostats are a Honeywell Digital with battery.
  • SteveSan
    SteveSan Member Posts: 234
    @rick in Alaska the resistors that come with each ZVC & SR controls are 1000ohms .5watt
    rick in Alaska