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need help replacing boiler zone valve-wiring

steve_25 Member Posts: 36
Have a 2 zone boiler with Honeywell zone valves. Last year had one of the zone valves replaced..actually the plumber just replaced the powerhead, no need to replace the body and solder etc. He replaced a 8043E1012 with an 8043F1036 (again w/o changing the body). I need to replace the other existing 8043E1012 with a new 8043F1036 (which I have). What I most confused about is the wiring. The new models have external wiring blocks/terminals while the old just has wires coming out the bottom (all hard wired within). So when I do cut the wires from the old, I will be holding 2 yellow wires and 2 red. I know by looking at the recently installed other zone valve that the yellow go the pipe side of the terminal block, and the red to the "front" side (which is the end switch terminals)...but which yellow goes to which screw which red to which screw or doesn't it matter as long as both yellows are in the back and both reds in the front? Hope u follow, its hard to explain.


  • Tim McElwain
    Tim McElwain Member Posts: 4,477
    The two yellow wires

    go to the motor in zone valve - one lead from the transformer is typically connected  to the one "yellow" - the other wire from the transformer should go to the thermostat - and the other "yellow" to the other wire from the thermostat.

    The "reds" are your end switch for the zone valve and go to TT on the relay.


    on the V8043F the two wires from the transformer go to TR and the two wires from the thermostat go to TH and the two wires which were attached to "red" go to the TT on the relay (if that is what you have) or to T and TV depending on the relay.