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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.