Taco zone valve

ppac

I have 2 zones and one keeps telling the boiler to fire . Temp in the house is 80. Originally there was no heat .tech changed head now it is running too much. Am i correct that after it heats up the contacts at 2 and 3 close the circuit to the boiler? Could the spring in the body be broken and its not driving the piston back up to break the connection at 2 and 3? If this is thr case does 2 and 3 get made when you pull the manul lever? Any help appreciated

Zman

This sounds like and older 3 wire.
A picture would help.

lchmb

if the manual lever is down he left it in the manual position and will over heat the house. The lever needs to be in the up position. If the lever works easy up and down the zone head has a call for heat and something is wrong with the wiring and or thermostat.

ppac

Thank you for the reply. Ill get a pic as soon as ii can. The lever was up. Also he removed the 1 eire and the boiler still would call for heat. Thought maybe 2 and 3 were somehow not breaking contact. Boiler runs even when the second zone that runs fine is off thats how the house gets so warm. Didnt start till bad head was replaced. On a normal system if you pull the manual arm does it make contact between 2 and 3? If the spring in the body is bad would it not drive the piston back up to break contact between 2 and 3. Ive been reading alot aboit these 3 wire taco zone valves. Again i appreciate the help

neilc

maybe its the other zone ?
try pulling a wire on this zone,
does it stop?
try pulling a wire on the other zone,
does it stop?
pull the wires on both of them,
does it stop?
maybe it's the controller.

STEVEusaPA

Did whoever replaced the zone head cut power to all the affected equipment? Sometimes the transformer that powers the zone heads isn't on the same circuit as the shut off for the boiler. You could've shorted something.
Could be a bad end switch on one/both heads, wired wrong, low voltage short, or a problem with the aquastat. Get out your meter.

unclejohn

I wire them like this. Power or "R" from the tsat to the middle or #2 terminal. Common or "C" from the transformer to and through the tsat to the top or #1 terminal. Common from the trans. also goes to the coil of my isolation relay. The bottom or #3 terminal goes to the other side of the coil on the isolation relay. Then the "TT" terminals of the boiler go across the normally open contacts of the isolation relay. Sequence of Opp as follows. Call for heat tstat closes brings power to ZV at terms. 1 & 2. Valve strokes open brings power to iso. relay through commonn wire and closed 2 & 3 terminals on ZV. Easy peasy japanezy.