Adding a C Wire to Burnham Boiler

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  #1  
Old 09-11-14, 05:37 PM
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Adding a C Wire to Burnham Boiler

I have Burnham boiler model P-207A-WNV and want to add a Wifi thermostat that requires a C Wire. Currently there are only 2 wires going to the thermostat and I will be running new wire to accomplish this. I cannot seem to find any information on my model number and was wondering if someone here could help.


Thanks,
Andy
 
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Old 09-11-14, 06:19 PM
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You need to locate where the thermostat wires connect to the boiler.
Post a picture of the controller or post the model number.
 
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Old 09-12-14, 04:20 AM
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PJmax,

I have attached some pictures. The T-Stat is connected to one of the 4 zone controllers (Taco) and the boiler model is P-207A-WNV. The last picture is the wiring for the emergency switch which is the only thing inside the service panel. There are 2 transformers mounted on the side of the boiler.

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Andy
 
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Old 09-12-14, 04:23 AM
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There would be a C connection there in that wiring.
Is that the only transformer in the system ?

Four zone valves and the WiFi thermostat may be pushing the limits of that transformer.
 
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Old 09-12-14, 05:14 AM
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Hi Andy,

There are 2 transformers mounted on the side of the boiler.
Can we see these transformers please?
 
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Old 09-12-14, 05:41 AM
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OK here are some more pics.

Here are the outside transformers
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Here is transformer inside the service panel. The white wire is connected to a terminal labeled "C" and the other end connects to where the pilot lighter is located
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Andy
 
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Old 09-12-14, 07:14 AM
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I am running the wire now and wanted to know if I can use 22 gauge alarm wire in place of the T-stat wire?

Thanks
Andy
 
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Old 09-12-14, 12:41 PM
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I am going to be in a similar situation... Only in my case, I decided to use a 'wall wart' to power the new stat (ie, the two wires would go to the boiler, the other to the wall wart).

Is that not an option for you?
 
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Old 09-12-14, 12:41 PM
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Well, I guess you can use whatever you want, but my recommendation would be thermostat wire, in general, 18 gauge... 22 gauge is pretty thin stuff, I'm surprised they use it for alarm wiring even.

You can't use that "C" terminal inside the boiler as the C wire for your thermostat. While it may be a common, it's not on the 'same circuit' as where you need to get your C wire from.

Those two transformers on the side of the boiler are most likely, almost certainly, (we can't tell for sure without being there) being used to power the zone valves. Each transformer is probably powering 2 of the valves. (I think there are only four valves?)

The "C" wire for the new thermostat has to come from one of the terminals on one of the transformers, but without examining the wiring, we can't really tell you which one.
 
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Old 09-12-14, 02:24 PM
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Thanks NJ Trooper,

Yes there are 4 valves. I traced the wires from the 2 side transformers and the bottom one is feeding the valve I am replacing the wiring on. Would I connect the C wire to the terminal on the transformer that has the white wire connected to it?

FYI: I bought some thermostat wire today as I agree that the alarm wire looked too small.
 
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Old 09-12-14, 03:43 PM
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We can't tell colors but the C terminal would be the one that goes directly to terminal 2 on the zone valves. There should be a jumper between the two #2 terminals on the zone valves in question.

Good move on the correct wire.

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Old 09-12-14, 03:43 PM
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Would I connect the C wire to the terminal on the transformer that has the white wire connected to it?
Installers don't always pay strict attention to color codes... so it may not be the white wire you need.

In other words, even if the transformer has " R " and " C " embossed at the terminals, doesn't mean that's what they are.

I'm searching right now for a graphic I posted a while back that shows how to add a "C" wire for Taco valves but can't find it...
 
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Old 09-12-14, 04:16 PM
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Couldn't find it, modified a drawing I did for someone else.

PJ is correct, presuming that your wiring is correct to start with.

Ignore the wire colors in this drawing, it's the connections that must be correct. Electrons don't really care what color the wire is!

 
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Old 09-12-14, 06:19 PM
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Thanks PJmax and NJTrooper,

I will connect the C wire as shown and let you know what happens.

Andy
 
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Old 09-12-14, 07:17 PM
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Before you do, please verify that your wiring is currently as shown in that diagram!
 
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