Pump Control

Alan (California Radiant) Forbes

One of my customers has three Taco ZVC 406, non-EXP controls. He originally wired his boiler and system pumps through his Viessmann boiler, but we may be changing that. What would be the easiest way to wire those pumps via the Taco controllers?

Zman

I think I would use a DPDT relay with a 24 volt coil. All 3 controllers could trigger the coil if their pump switches were wired in parallel.

Alan (California Radiant) Forbes

I was thinking about a pump relay like a Taco SR501, but I guess that is the same thing you suggested.

Zman

Alan,
Yes, the same thing, The great thing about the 501 is the simple package and built in transformer. It is also nice that the Taco guys come on heating help and answer our stupid questions
Carl

Joe Mattiello

Hi
regarding Taco, 3 ZVC controls and system pump wiring scheme, if you don't have need for priority, and can parallel all your end switches so boiler fires on demand from any 3 ZVC controls. you can use a SR501 for the circulator bringing end-switch from 3rd ZVC wired in parallel to R-W terminals on SR501, and use the end switch terminals on SR501 to boiler TT terminals.
Hopefully this was helpful. If you require additional support, you can call Taco at 401-942-8000 and ask for Tech support. Any problems along the way you can always reach out to me:)

Dave H_2

I'm thinking thSR 501-EXP is a better fit. It has the circulator output for the zone circ and also has a terminal for the primary (boiler) circ. All of the EXP controllers have this primary terminal.

Dave H.