Heat won't shut off

Steve Garson_2

I have a WM GV boiler with five zones. Today is a 60 degree day and I noticed that two rooms are blazing hot, even though the T-stat is set at 65. I removed the T-stat to see if that was the problem, but this one zone is still circulating, with the burner firing intermittently. All the other zones are fine.

How do I stop this until a service person can come. There are four wires to the zone valve. Is the issue the zone valve?

Any help would be appreciated.

Steve in Denver

nicholas bonham-carter

Can you shut off the gas?—NBC

Steve Garson_2

I just cut one red wire on the valve and it solved the problem.

JohnNY

I'll assume your "4-wires" are from a Honeywell zone valve. The red wires are from the end switch which are the ones that complete the boiler's low voltage power circuit to the gas valve. If the thermostat is satisfied, I'm going to assume you've got a bad end switch or the gearing in the zone valve has gone bad. In either case, replacing the zone valve's electronic head is the way to put this to bed.
But then again, we all know what happens when we assume.

Steve Garson_2

Thanks John. The actuator is 30 years old. It served us well. Just ordered a new one. I should probably replace the others to prevent a failure when it’s cold out versus springlike.

SuperTech

Just make sure when you remove the zone valve motor that the innards of the valve move freely and easily. If it requires any force to move it I would replace the guts of the valve. This can be done by removing the 5/16" screws on the four corners of the valve body. Of course you will have to drain, refill and purge the zone to do this, unless you had a good installer who put isolation valves in all the right places.

Zman

Installing a zone controller like Taco or Calleffi make life much easier with those zone valves. It will tell you the status of the call for heat and end switch. I agree, change all of them. They are not that expensive and it takes little time to do the others once you are set up.

SuperTech

Zone control panels should be required by code. 90 percent of the zone valve jobs I see are a bird's nest of wires and splices and just a complete mess. Zone valve panels eliminate that and the end switches on the zone valves that tend to fail.
With a zone panel the wiring looks neat, reliability is increased and troubleshooting simplified.

Solid_Fuel_Man

Most jobs I do now, we use Delta P pumps which eliminates those pesky end switches. Or with a zone valve control board you can just short the end switch pins and run them as 2 wire valves. It's nice to have a built in delay and the pump won't dead head while the valve travels open.

SuperTech

> @Solid_Fuel_Man said:
> Most jobs I do now, we use Delta P pumps which eliminates those pesky end switches. Or with a zone valve control board you can just short the end switch pins and run them as 2 wire valves. It's nice to have a built in delay and the pump won't dead head while the valve travels open.

It's nice. I combined an Alpha 2 and Tekmar zone board on my boiler at home. The Tekmar controls four two wire zone valves, the Alpha 2 to pump my zones, a VT2218 Injection pump and DHW priority control for my boilermate. No birds nest of wires. 😄