No end switch

Dud

We have a newly installed Navien combi system. A Taco zone controller is used to provide 6 zones. There are 3 "manifold" locations with 2 zone connections. At each of these locations there are 2 V8043 zone valves with individual 3 wire thermostats. The problem is that the cable back to the boiler only has 6 wires. Ideally, I should have 3 for each thermostat and 4 for each valve, or 14 wires for the 2 zones. The Taco would sense the thermostat call for heat, and activate the corresponding valve. The end switch would be detected by the Taco. The Taco connects to the boiler to fire the gas and turn on the circulator. But I'm short on wires. It dawns on me that the thermostat itself can activate the valve. So I can make it work with just 3 wires to each thermostat (and connect the stat W and C wires to the valve). But I don't have wires for the end switches. The Taco can turn on the pump and boiler. Can something bad happen by "assuming" the valve has actuated because I can't connect the end switch?

Thanks.

Jamie Hall

Eh? You want the boiler to fire when any zone valve is open? Connect all the end switches in parallel…

hot_rod

If the zone valves are remote, yes, you need to get the end switch connections back to the relay boxes.

Two wires from the stat to the relay box for the heat call, 4 wires from the zone valves to the relay box.

Maybe it had 3 wire zone valves in the past, like the Taco 571?

Or switch to a delta P type circulator, keep it powered up, it responds to zone valves opening and closing. A flow switch would call the boiler on. Two wires from stat to relay box. Two wires from relay box to zone valves.