How to wire Taco zone valve controller to boiler

jeremypbeasley

Hi all! 

I’ve got a Weil-McLain CGa-5 boiler that was previously set up as a single zone system. I’ve converted the house into a 3 zone system using Taco zone valves and a Taco zone valve controller, still using a single circ pump. 

Previously, the wiring was much simpler. The thermostat connected directly to the boilers control module and the circ pump did as well.

Now that I’ve introduced the zone valve controller and wired thermostats directly to this, it’s unclear to me what kicks on the boiler for a heat call.

The Taco videos outline how to wire the circ pump into the zone valve controller but there’s no mention of the boiler. 

What am I missing? If the zone valve controller kicks on the circ, what triggers the boiler to kick on? 

Here’s some pics of both the zone valve controller and the boilers module. 

offdutytech

If you look at the top row of connections on the left of the zone control panel that says " isolated end switch". You simply take two wires and wire it to your thermostat connections on your boiler. It throws some people off with calling it an isolated end switch, it's just isolating the boiler or equipment control circuit from the zone valve transformer. 

Joe Mattiello

Think of the ZVC control as a facilitator for multiple zones. Thermostats at top, and corresponding zone valve at bottom. 

You have dry contacts at top of control that will be the only interface with boiler, wired to TT terminals using 18 gauge wire.
you can leave circulator on boiler aquastat to energice with a demand from any zone. 

Pretty straightforward. If you have anymore questions feel free to contact Taco tech support at 401-942-8000

jeremypbeasley

Joe Mattiello said:

Think of the ZVC control as a facilitator for multiple zones. Thermostats at top, and corresponding zone valve at bottom. 

You have dry contacts at top of control that will be the only interface with boiler, wired to TT terminals using 18 gauge wire.
you can leave circulator on boiler aquastat to energice with a demand from any zone. 

Pretty straightforward. If you have anymore questions feel free to contact Taco tech support at 401-942-8000

Thanks so much! For posterity’s sake and anyone else who reads, what’s the advantage of leaving the circ connected directly to the boiler vs to the zone controller? 

cubbydog

I have a question about the end switch on a taco sr504-4 zone controler? The directions say to put the isolated end switch to the TT on the aquastat relay. The problem is there is only an high limit aquastat on the boiler.
Do I do nothing or put a jumper on the isolated end switch?