Connecting taco sr501 and hydrostat 3150

benmoussa3 · January 2022

Hi I have a tankless and circulator 1 on Hydrostat 3150 and another zone on Taco SR501, zone 1 works perfectly, however Zone 2 turns on the Circulator 2 but it doesn't fire the boiler... whoever made this install used the Typical Wiring (Cold Start) and didn't connect 6 (N/O) and 5 (COM)... what should I do in this case? I would like Zone 2 to fire the boiler if thermostat is calling for heat. Thanks

Note: TT on boiler is already used by Zone 1 Thermostat

Jamie Hall · January 2022

I wonder if this is the whole of the wiring? But if it is, there's no reason you can't connect 5 and 6 on your zone relay to T-T on the boiler in parallel with any other thermostat or relay (not, however, in parallel with the one already controlling the same relay...)

Robert O'Brien · January 2022

If you want the reverse function of 3150 to operate with both zones, wire per middle diagram, if you just want zone 2 to bring on burner, run power from #4 terminal of 501 to ZR on 3150