One zone not working in my heating system


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Old 03-27-13, 12:33 PM
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One zone not working in my heating system

I have a 10-year old house. I have for heating zones for my Weil-Mclain Gold CGs boiler. Two zones upstairs, one for the hot water heater and the last one is the in-floor heat in the basement. This zone has a digital Wirsbo thermostat. The basement zone isn't working. The temperature has been slowly dropping in the basement. I'll try to explain what's happening when I adjust the thermostat:

1. When I turn the temperature up on the thermostat, the icon on the thermostat display's the blinking fire icon which signifies a call for heat. In the boiler room, the Honeywell zone valve opens up, but the boiler never comes on.

2. When I turn the thermostat down below the current temperature, the call for heat icon turns off and I can hear the zone valve closing.

The other zones seem to be working fine.

Any thoughts? Thanks.
 
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Old 03-27-13, 01:24 PM
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Inside the control head for the zone valve is a small switch that closes and makes contact when the valve opens.

This switch is supposed to call the boiler to fire when the valve opens.

Sounds as if it's not making contact, which is fairly common with these valves.

If you've examined all of the wiring and all is good, then it sounds as if the control head on the zone valve needs replaced.
 
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Old 03-27-13, 01:35 PM
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If your zone valve has an "end switch" that controls the boiler (denoted by having four wires on the zone valve) then more likely as not the end switch is not closing to signal the boiler. If you have the radiant floor thermostat turned up to call for heat and then actuate another zone via its own thermostat do you get heat to the floor?
 
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Old 03-27-13, 02:43 PM
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That sounds right to me. The signal is making it to the zone valve, but it is not making it from the zone valve to the boiler. Does the whole zone valve need replacing, or just the control head? Is it a simple repair, or should I have a professional do it.
 
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Old 03-27-13, 04:02 PM
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It can be simple... depending on the age of the valves, or it can be more difficult requiring draining the system if you have the 'old style' valves.

What is the model number of your valves? V8043 ? if they have wires, 2 yellow and 2 red, they are the "E" model, if they have terminal blocks, they are the "F" model.

Slide the cover off the valve.

Look for the screws that hold the power head to the valve.

There will either be FOUR SCREWS (OLD STYLE, REQUIRES DRAINING),

OR, only TWO SCREWS and TWO LOCATING PINS (NEW STYLE, NO DRAINING REQ'D)

Let us know this and we can advise further...
 
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Old 03-29-13, 06:20 PM
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I'm not home right now, but the valves are Honeywell. The end of the valve that has the wire terminals has: 2 screws on top. I believe this wire comes from the thermostat. 2 screws on bottom, with wires that go to the boiler.
 
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Old 03-29-13, 07:15 PM
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Sam, I don't mean the wire terminals when I talked about two screws.

But what you've said tells me that you probably have the V8043 F Honeywell valves.

The screws I was talking about are INSIDE the cover of the valve. You can't see them unless you remove the cover. These screws go through the baseplate of the control head into the body of the valve.
 
 

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