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View Full Version : Wiring old taco zone valves 555-102 to furnace


2N2L
Mar 23, 2008, 05:33 AM
Help! I have a two zone system of water base boards hooked up to an oil furnace (or is it a boiler?). I had it serviced a month ago and I just realized that the wiring on the two zones, which are controlled by taco 555-102 zone valves, was reversed so that the wrong thermostat controlled the wrong zone. I tried to fix it and now have completely messed up everything. :(

Here is the wiring that I have:

I have two sets of wires coming from my thermostats, they are simple red and white wires.

I have one set of wires going to the furnace they are white, green, and red. The white and green ones on the furnace wire are stripped at the ends and a bit up so that they can connect to both of the zone valves at the same time.

The zone valves each have three screws: from front to back s1 s2 s3.

Most of the advice I have found online has referred to additional wires like yellow, but these are all I have. Any help would be appreciated!

Thanks,
Kenn

hvac1000
Mar 23, 2008, 10:02 PM
Terminals 2 & 3 go to the circulator relay. Terminal 1 goes to one of the thermostat wires. The other thermostat wire goes to one side of the 24 volt transformer that powers the zone valve and the other transformer terminal goes to Terminal 2 (also)