Gas boiler won't turn off


  #1  
Old 01-17-19, 06:41 PM
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Exclamation Gas boiler won't turn off

We have 2 zones with two thermostats. Although it's winter, the A/C came on today so I figured the one thermostat went bad. I switched it from automatic (A/C or heat) to heat only and the heat kicked on. It will not t shut off.

My solution was to take the 2nd thermostat and put it on the main zone to get the heat to stop. That does not work either.

It seems like the zone valve is stuck open. Is there a relay or limit switch that has to close to stop the heat?

Thank you.
 

Last edited by syakoban; 01-17-19 at 07:05 PM.
  #2  
Old 01-17-19, 07:35 PM
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If you have zone valves..... removing the thermostat would remove power from it and it should close. If it is not closing then it may be jammed.

When you say the heat is stuck on..... is the zone getting too hot or is it the boiler keeps running ?
There is usually a slide lever on the zone valve for manually opening it. If the slide lever moves easily.... the valve is open. If the lever is hard to move..... the valve is closed.

Hard to give more detailed help without knowing what you have there. Some pictures of the general system and zone valves are helpful.....How-to-insert-pictures
 
  #3  
Old 01-18-19, 07:37 AM
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The lever was loose but not having any effect. I believe the valve motor is jammed open. I pulled the head off and then pulled a wire and the heat immediately shut off.

I'm now able to control the whole house from the known working thermostat with both zones getting hot water circulating.
 
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Old 01-18-19, 12:57 PM
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So you don't know if it's a wiring problem or a valve problem.
If you pulled the wire off first.... before removing the valve.... and it stayed open.... it's the valve.
 
 

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