Wiring a three wire zone thermostat


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Old 11-22-14, 05:28 PM
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Wiring a three wire zone thermostat

Hi everyone, I have a boiler with three wire zones and am having a hard time getting thermostats wired. There are old mercury switch whites-Rodgers thermostats with red, white, and green wires hooked up to terminal 4,5 and 6 (in that order). I purchased some Emerson 1f80-0471 that are supposed to be three wire compatible. I have been unsuccessful getting them to operate, the zone opens but won't close.

One of the zones had a Honeywell rotary-style thermostat on it, and I replaced that one with a 1f80 with no problem, wiring as follows:
Red to RH (with jumper to RC, but was told I can remove jumper since no cooling)
White to o/b
Green to W

The other zones will not work on this configuration, I don't want to mess with them too much more as I managed to blow a transformer a few days ago. My HVAC guy would only tell me that they should all be wired the same way (think he just wants me to pay him to do it).

Please help!!
 
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Old 11-22-14, 05:57 PM
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Welcome to the forums.

Do you have three zone valves ?
The thermostats should be connected with two wires. A third wire should only be needed if you need power to run a thermostat. In your case.... yout t'stat does require a Common connection for the blue display.

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Old 11-22-14, 06:21 PM
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The thermostats should be connected with two wires
Not necessarily.

Once we hear "White Rodgers" we know that these zone valves require 3 wire thermostats to operate.

They are POWER OPEN, AND POWER CLOSED.

The thermostats for these are Single Pole DOUBLE Throw (SPDT)

Mules, please tell us what model zone valves you have.

I'll write more later...
 

Last edited by NJT; 11-22-14 at 07:03 PM.
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Old 11-23-14, 07:13 AM
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The zone controls are Whites Rodgers 1311-102s. The grey/black body ones with the rotary dial that opens and closes them
 
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Old 11-23-14, 07:27 AM
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red, white, and green wires hooked up to terminal 4,5 and 6 (in that order)
You need to double check that because it doesn't sound right.

If you have WR thermostats they should be wired:

White to 4

Red to 5

Green to 6

This is according to the zone valve manual, not my less than stellar memory.
 
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Old 11-23-14, 07:36 AM
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One of the zones had a Honeywell rotary-style thermostat on it, and I replaced that one with a 1f80 with no problem, wiring as follows:
Red to RH (with jumper to RC, but was told I can remove jumper since no cooling)
White to o/b
Green to W
Regardless of WIRE COLOR...

O/B terminal of thermostat goes to zone valve terminal 6

W terminal of thermostat goes to zone valve terminal 4

R terminal of thermostat goes to zone valve terminal 5



If you've got different color wiring going to different terminals, that's the source of your confusion. You must have the right terminals connected to the right terminals. Electrons don't care what color the wire is.
 
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Old 11-23-14, 07:38 AM
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Right, on the old WR thermostats that's how they were wired, on these new ones there is no 4,5,6.

There's RC, RH, C, W, Y, G and O/B. The zone controls ARE wired at 4,5,6. One of the reasons I'm confused about all this is that, as I posted earlier, one of the zones is working on a 1F80-0471. That zone control also has wires at 4,5,6.
 
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Old 11-23-14, 07:41 AM
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Regardless of WIRE COLOR...

O/B terminal of thermostat goes to zone valve terminal 6

W terminal of thermostat goes to zone valve terminal 4

R terminal of thermostat goes to zone valve terminal 5
 
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Old 11-23-14, 08:13 AM
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So I double checked wires, and ran them as you said, Trooper, and nothing. I went down and checked zone control, touched a wire, and there was a loud buzzing, and the burner shut off. It fired back up, but now the zone control won't close, even if I manually spin the rotary wheel.

I'm guessing that maybe there was an electrical issue with the zone control?
 
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Old 11-23-14, 08:28 AM
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I'm guessing that maybe there was an electrical issue with the zone control?
Either that, or your previous mishap of burning out a transformer has damaged either the thermostats or the zone valves in addition to the transformer.

Tell me what happened when the transformer burned out. What were you doing? What did you have connected?
 
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Old 11-23-14, 08:43 AM
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I had the thermostat connected in what should have been the right configuration. I slightly moved the bundle of wires (the brown part before they are separated) and there was a buzzing noise. The burner flamed out, then quickly re-lit. I shut the power to the boiler down, reconnected the old WR thermostat in it's previous config, turned the power back on to the boiler. Nothing now. I believe the zone controls are near the end of their life anyways, but this whole thing has been aggravating. We just bought this house two months ago and had to replace the boiler after three days.
 
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Old 11-23-14, 10:13 AM
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We just bought this house two months ago and had to replace the boiler after three days.
Really? Why? No insurance or 'recourse' with the seller?

I slightly moved the bundle of wires (the brown part before they are separated) and there was a buzzing noise.
Sounds to me like bad connection.

Can you take pictures of the wiring please?

I believe the zone controls are near the end of their life anyways,
White Rodgers valves are one of the best in my opinion. I doubt they are near end of life.
 
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Old 11-23-14, 10:17 AM
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I think there's a 'timeline' issue here. In your first post you said:

I don't want to mess with them too much more as I managed to blow a transformer a few days ago
And then when I asked you this:

Tell me what happened when the transformer burned out. What were you doing? What did you have connected?
You replied:

I had the thermostat connected in what should have been the right configuration. I slightly moved the bundle of wires (the brown part before they are separated) and there was a buzzing noise.
I didn't want to know what JUST happened, I wanted to know what occured before you posted your first post. How did you burn out that transformer? How do you know it didn't damage the thermostat?
 
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Old 11-23-14, 10:18 AM
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My HVAC guy would only tell me that they should all be wired the same way (think he just wants me to pay him to do it).
Sounds to me as if you might have been ahead of the game if you did...
 
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Old 11-23-14, 10:34 AM
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So def some kind of wiring issue. Cut power, pushed wires where they connect to zone and now I have control via old WR thermostat. Thanks for the help, I'm done trying to figure it out.
 
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Old 11-23-14, 04:01 PM
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I'm done trying to figure it out.
Meaning I should 'stand down', you've given up?

It's probably just a loose connection that a close visual inspection should find.

Oh well..........................
 
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Old 11-23-14, 04:26 PM
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LOL thanks for the info. What I mean is it's working for now and I have other projects that need attention. Thanks again!
 
 

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