ZVC404-4 Zone Valve Control, 4 Zone

Had a lower-tier Taco ZVC in place with a high-efficiency Utica boiler before. That Taco didn't have a priority circuit for DHW so the installer jury-rigged a series of relays to accomplish the same thing. One of the relays (I assume) started going bad so the central heat circuit wouldn't always flip back on when DHW thermostat flipped off.Going from Taco to Taco was pretty seamless, except that the first one (Used, Like New through Amazon Warehouse) arrived with a loose connection between transformer and PCB. No problem; returned and bought new.FWIW, the Taco assumes that current needs to be going to the boiler pump end switch(es). The Utica I have just needs dry switches for DHW and CH pumps; I was able to figure this out without much trouble, but a note about this in the installation manual would be useful.

I bought this controller because I wanted to use some smart thermostats and I couldn't hook them up with the existing wiring. I like the status LEDs that tell you when a thermostat is calling for heat and when the valve opens. I found a bad zone valve after hooking up the controller.

Bought this just so I could add a common wire to my older two-wire zone circulator. (2 zone valve loops & a zone circulator radiant loop). Silly, huh? But ZVC was easy to install, well organized zone valve control with LEDs to show status of zones. Also includes relays to control AC power to system, secondary, and DHW circulators. But relays didn’t work the way I expected. The main pump end switch triggers system circulator when ANY of the 4 zones are active (duplicates the isolated end switch for boiler TT). There is a separate “priority” relay triggered only by zone 4, so I expected the primary pump end switch would be triggered only by zones 1-3. I couldn’t get system circulator and radiant circulator to run independently - it was either always running both circulators, or letting the zone 4 relay disable the main circulator when radiant zone circulator was turned on. I would have preferred the main pump relay to only activate for zones 1-3, and the zone circulator driven by zone 4.I resolved this by moving the zone circulator to a separate SR501 zone relay, so now the two loops are truly independent. But the boiler wiring is now very clear, well labeled and neat, with common wires and self-contained 24VAC transformers, and independent circulator controls. So I’m still happy with the ZVC.

Hooked it up and it works great.

You can never go wrong with a TACO pump, zone valve or computer. But remember, you just cant buy them at the Taco Bell drive through ;)

Love it easy to install I can see it saving me a lot of money very nice unit I bought the 4 zone the price difference was only a few $ and in case I ad a zone or one of the zones on it goes bad I have back up

only needed for 2 zones but if one goes bad there are 2 as a backup.

Works Better than I expected. 4stars because Could use a schematic of the relays. Although I was able to figure it out it would not be easy for the everyday DIYer. I Used this to control the zone valves in my hydronic heated floors. And a hot water circulation loop. Works great.