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Taco zone valve issue

Ptodd's Avatar

Join Date: Oct 2017
Posts: 1

10-11-17, 06:08 PM   #1  
Taco zone valve issue

greetings all!

old fast attack sailor looking for some help solving a frustrating boiler issue

i have a taco control panel and six Taco zone valves, wired through "round" Honeywell thermostats.

only one zone cycles on and off, about every 20 minutes during the day

looking at the control panel, it appears the thermostat is calling for heat, and the zone valve opens, and the burner turns on, but before it fires the process stops, as if the thermostat was satisfied.

tried replacing the thermostat with known working, but no joy.

my heat guy says that it's an issue with Taco Zone Valves and that a possible cure would be going

Last edited by ray2047; 10-11-17 at 07:38 PM. Reason: Clarify Title.
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spott's Avatar

Join Date: Oct 2013
Posts: 1,902

10-12-17, 07:21 PM   #2  

You have 1 Taco 6 zone control panel with 6 ZV's attached.
Are you saying only 1 zone is working or 1 zone is not working.

If only 1 zone is working it's highly unlikely 5 zone valves or 5 t-stats are bad. With the limited info you provided I would look at the control itself as it is the common denominator in this case.

If you want to check the stat you can remove the stat from the base and jump the 2 wires together and the ZV should open and the boiler and pump should start if it is a cold start application. If you get your hot water from the boiler when the temp drops low enough the boiler should come on.

In either scenario the pump should start right away. You can try every zone the same way.

If the zone valve opens on a call for heat then terminals 2 & 3 on the ZV start the boiler and pump. If the valve opens but the boiler does not start it could possibly be the ZV.

Hope this helps a little.

PJmax's Avatar
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Join Date: Oct 2012
Posts: 41,940

10-12-17, 07:44 PM   #3  
Welcome to the forums.

If it's a Taco 6 zone controller..... I don't believe it uses the zone valve switches to start the boiler. The boiler should be under direct control of the controller.

I guess at this point we need to know what controller, if any, is in use.
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