Boiler ignores thermostat calls after zone valve replacement

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  #1  
Old 11-19-20, 05:03 PM
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Boiler ignores thermostat calls after zone valve replacement

Hi there, I replaced a zone valve end switch (Honeywell v8043f 5000 series) for my three zone boiler system. After I replaced it, I noticed my boiler ignored the thermostat calls. If I take all the zones down to just one, I can have the boiler run for a few minutes and then shut off, and repeat this unless I cut the power to the boiler. However, if I have all or one zones wired up, I can get the boiler to fire and run if I press and hold the microswitch. But the boiler continues to ignore the thermostat calls.

There is an external transformer on the boiler. My boiler is a burnham es2. Ideally I'd like to get all three zones wired up so they can call the boiler for heat independently, but right now I'd settle for just one zone to be wired properly and be able to call the boiler from the thermostat.

I've tried following the wiring diagrams online but I think I'm getting something bass ackwards, or there's something else going on beyond the zone valve.

Thank you for any insight anyone can provide!
 
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Old 11-19-20, 05:35 PM
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Welcome to the forums.

Are those the valves with screw terminals or the two red and two yellow wires ?
 
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Old 11-19-20, 06:52 PM
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Hi Pjax, thanks for the welcome. It's a screw terminal valve. I've attached a couple pictures if that helps. Right now it's just wired for one zone but you can see the other two zone valves. In this setup, boiler is not cycling on its own, but will not accept a call from the wall thermostat but will run normally if I push the microswitch on the valve.

The wiring right now is: "end switch" to TT on boiler
TH-TR empty (dummy terminal)
TH thermostat on wall and external transformer (white wire)
TR thermostat on wall and external transformer (red wire)


 
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Old 11-19-20, 07:42 PM
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Ok.... it's wired incorrectly. The end switch wiring is correct. The stat is not.

The Th-Tr terminal is just a splice point. It's not needed and you aren't using it.
One side of the transformer..... call it R goes to the R terminal on the stat,.
The other side of the transformer.... call it C goes to Tr terminal.
The Th terminal connects to W on the stat.

 

Last edited by PJmax; 11-19-20 at 09:22 PM.
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Old 11-19-20, 08:09 PM
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With this wiring, the boiler still ignores the thermostat but happily runs when the microswitch is pressed. Did I misinterpret your very helpful diagram?

 
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Old 11-19-20, 08:22 PM
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Ignore the Th-Tr connection. It's just a dummy. A splice point. You don't need to use it.

If the red and white coming from the bottom are power
and the red and white going to the top is the stat..... it should work.

You can operate the valve by putting 24v directly on Th and Tr.
That will bypass the thermostat and open the valve.
 
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Old 11-19-20, 09:08 PM
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So my husband read the thread and has:

Thermostat red and transformer red - hatted* (he was confused by the splice point not to be used but the drawing showing it in use?)
White from thermostat on TH
White from transformer on TR

With this configuration we are still in the same situation as we were in the beginning of the thread.

* my husband wishes to say "the wires are spliced" which apparently is the more technical term. The twist on connectors look like little hats to me.

I appreciate your help in all this.
 

Last edited by Zonevalvewoes; 11-19-20 at 09:11 PM. Reason: clarification
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Old 11-19-20, 09:25 PM
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I changed my previous diagram to eliminate the splice point.

Try connecting 24v directly to the zone valve on the Th and Tr terminals.
Does the valve open ?
If the valve does open..... you need to figure out why your thermostat is not creating the needed short.
If the stat has an Rh terminal.... be sure to use that.
 
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Old 11-20-20, 10:26 AM
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Here is where we are today:

Boiler is bypassing valve but runs for 2 minutes, shuts off for 3 minutes, repeat.
Radiators have been bled. We had some air come out but not much.
 
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Old 11-20-20, 01:05 PM
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Hi, did you get a wiring Dia. with those valves? First identify the wires from the Stat, then the wires going to TT on the boiler control, and then 24 VAC supply.
Post a pic of the terminals on the valve, itís hard to read them it the pic you posted.
Geo 🇺🇸
 
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Old 11-20-20, 01:25 PM
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Z,
As simple as I can make this I hope.

You have 2 transformer wires and 2 t-stat wires.

Put 1 transformer wire to TR on your zone valve
Put the other transformer wire to TH/TR on the ZV.
Put 1 t-stat wire to TH/TR on the ZV
Put the other stat wire on TH on the ZV.
That will take care of your ZV,/ STAT series wiring. You willl have 2 wires on the TH/TR terminal. 1 for the STAT & the other for the TRANSFORMER.
The 2 end switch wires go to the boiler or whatever control you have on your boiler that turns it on.

If you had the ZV with the RED & YELLOW wires the 2 RED would go to the boiler and the 2 YELLOW would go to the STAT.

Hope this helps a little.
 
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Old 11-20-20, 02:49 PM
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While we triple checking our wiring, we noticed our boiler's pressure gauge was reading 0. We called in a professional who replaced the valve that sits on top of the expansion tank. He also rewired everything -- and it STILL ignored the thermostat, but would run with the switch pressed.

He tested voltage at our transformer where we were not impressed to learn that it was reading 0V. As of now he is working on replacing the transformer.

So, we actually have multiple problems with our boiler, beyond the wiring.

I really am starting to dislike this boiler. But at least it is getting everything taken care of at once. I'm annoyed it all crapped out at once, but at least that saves us from having multiple service calls.
 
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Old 11-20-20, 05:56 PM
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Z,
Best of luck, at least it will be done. Let us know how you make out if you can.
 
  #14  
Old 11-21-20, 04:11 PM
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You burned out the transformer with your incorrect wiring as shown in your picture.
You connected the two transformer wires together.

You had the two thermostat wires connected directly to the transformer wires on the valve.
When the thermostat called for heat..... it directly shorted the transformer out.
 
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