Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

Taco ZVC405-4

Options
BBrewer1411
BBrewer1411 Member Posts: 1
in Thermostats and Controls
I recently installed a used boiler for my 5 zone radiant hot water system, Burnham NG Series 2 Model 204 (Manufactured in 2007) I added a Taco ZVC405-4 Zone Valve Control Module that the T-Stats and zone valves are wired too. In order to use the Taco it required the removal of the Honeywell Relay and transformer from the Burnham so everything runs off the Taco.

2 wire T-Stats no power required, Honeywell zone valves 4 wire.

The 2 wire safety train leads are tied together and come from the boiler and attach to zone 5 on the Taco. Zone 5 works perfectly when call for heat is made. The damper opens, the gas valve opens, the blocked vent switch proves out.

The only issue is no other zone "call for heat" will ignite the boiler, open damper, open gas valve, prove out the blocked vent switch.

Ignition only happens when zone 5 calls for heat, so to heat the house zone 5 must be wide open all the time.

Boiler will circulate water but will not ignite on zones 1-4.

All zone valves work fine and all T-Stats work fine.

Its likely a simple wiring issue but Im stumped.

Any help is appreciated.

Comments

  • Snowmelt
    Snowmelt Member Posts: 1,415
    edited February 2020
    Options
    the boiler should be wired to xx on the taco board
    kcopp
  • SuperTech
    SuperTech Member Posts: 2,164
    Options
    Is zone 5 a priority zone? Perhaps it's just a matter of switching the priority off.
    kcopp
  • Alan (California Radiant) Forbes
    Alan (California Radiant) Forbes Member Posts: 4,002
    Options
    Mr. Brewer says that zones 1-4 will only work with zone 5 calling for heat. Kind of the opposite of priority.
    Snowmelt has the tiger by the tail.
    8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour

    Two btu per sq ft for degree difference for a slab
    SuperTech
  • HVACNUT
    HVACNUT Member Posts: 5,835
    Options
    > @BBrewer1411 said:
    > In order to use the Taco it required the removal of the Honeywell Relay and transformer from the Burnham so everything runs off the Taco.
    >

    ??? You removed the Honeywell control transformer/relay completely? That can't be. The lower left corner of the zone board "Main End Switch" terminals wire to R and G on the Honeywell relay.
    >

    > The 2 wire safety train leads are tied together and come from the boiler and attach to zone 5 on the Taco. Zone 5 works perfectly when call for heat is made.

    What's a safety train? The end switch wires? And why do they all attach to zone 5?

    Pics?

    The Honeywell control relay in the boiler must be used. Limit and safety circuits are controlled by that relay as well. It's not just a thermostat relay.
    Safety first.

Categories