Bad Zone Valve? Bad Zone Valve Motor?


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Old 11-27-07, 09:04 AM
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Bad Zone Valve? Bad Zone Valve Motor?

I have 4 zones on my boiler. All zones fine earler this season. I stopped using one of the zones for a few weeks and turned the thermostat down. Now, I turn the thermostat back up and I get no heat.

At the thermostat, when i turn it up, I see the small spark when the mercury shifts. I always take this to mean that the circuit is opening and closing properly.

The other zones all work fine so Im assuming it is the zone valve.

I shut the thermostat down and set the valves switch from auto to manual (test?) and still nothing. Does that confirm it is the zone valve?

If so, do I need to change the valve or just the valve's motor?
 
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Old 11-27-07, 03:49 PM
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Boy, a run of zone valve issues this week!

Have someone operate the thermostat slowly between heat and no heat call temps while you watch the zone valve to see if it is indeed operating. Most have a little lever that will move as the valve opens and closes. If the gears are stripped, or the motor or mechanism jammed, the lever won't move. If the motor does indeed operate the valve, then problem is most likely a miniature "Microswitch" that is closed when the valve is fully open. That is a common problem.

If you're electrically or electronically skilled, you could change a bad microswitch. Otherwise, the power head assembly can removed and replaced without disturbing the valve body.
 
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Old 11-27-07, 03:55 PM
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Zone valve

What brand of zone valve are you dealing with? Both Taco & Honeywell have the manual lever. If during a call for heat, the lever is easy to move it's full length of travel, the valve is opening & the problem is likely the end switch.
 
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Old 11-27-07, 03:58 PM
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What model zone valves ?

Manually opening with the lever won't activate the endswitch on a Honeywell zone valve. The endswitch is the 'microswitch' that Radio mentioned.

But yeah, look to see if the valves' motor is operating. If it is, I concur with RC that the endswitch could be not making contact and firing the boiler.
 
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Old 11-28-07, 01:25 PM
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It is a Honeywell.

Even on the good ones I couldnt see anything move when someone turned them on. But they worked fine.

But, on the good ones, the lever on the bottom moved freely the entire distance when calling for heat.

On the bad one, it did not move freely even when the thermostat was pushed up all the way.

So what does that mean?
 
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Old 11-28-07, 03:00 PM
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It does sound as though the valve is not opening on a call for heat... maybe a bad motor. You said you can see a tiny 'spark' at the t'stat, so I'm presuming the wiring is OK.

Try manually opening the valve and setting one of the OTHER zone thermostats to call for heat. You should feel heat in the bad zone.

Those motors are pretty easy to change...
 
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Old 11-28-07, 04:46 PM
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Ok, let me make sure I understand.

"Try manually opening the valve and setting one of the OTHER zone thermostats to call for heat. You should feel heat in the bad zone."

Is that the test to see if it is the motor?

If I manually open the bad zone (how do I do that anyway?), then when another zone (Im assumin any of the other three) calls for heat, then the bad zone will get it too?

The circulator will push water through any open valve when any thermostat calls for heat - is that correct?

So, the two things Im not sure of are:
1) how do I manually open the bad zone?
2) the motor isnt that hard to change - so I dont have to drain the water and replace the entire valve - is that right?
 
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Old 11-28-07, 06:17 PM
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Honeywell Zone Valve

To open the valve manually, push the lever all the way to the right then lift the lever & relax the tension a bit. The lever should lock into a notch. Sometimes, if the end switch is just worn but otherwise still functional, when you push the lever all the way to the right the end switch will close & bring on the circulator. Once the valve is locked open, hot water will begin to flow if the boiler is hot. Turning up another thermostat will bring on the circulator & force the hot water thru both zones. Once the troublesome zone is comfortable, release the lever from the locked position or that zone will continue to heat by gravity or whenever any other zone calls for heat.

You do not have to drain anything to change just a motor.
 
 

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