Gas Valve Wiring

Old 03-15-08, 05:50 PM
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Gas Valve Wiring

I'm getting ready to redo my Boiler and my eyes aren't what they used to be. I'm expanding from a 1 zone to a 3 zone system. I was looking at the gas valve to familiarize myself with the terminals and I found the print is to small to read. There are two terminals currently wired. One is marked TR and the thermostat wire runs through the Aquastat to this terminal. The other terminal is illegible and is wired from the transformer. I suspect it's TT but I can't see well enough to know for sure. Can anyone tell me what the markings are on the second wired terminal.


Old 03-15-08, 07:25 PM
Join Date: Mar 2006
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My eyes aren't what they used to be either. I use a bright flashlight and a magnifying glass in addition to my regular eyeglasses.

It really doesn't make a whole lot of difference which terminal goes to the transformer and which goes to the thermostat but the terminology is that TR goes to the transformer and TT goes to the thermostat. Sounds like yours may have been backwards and worked just fine.

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