One zone not opening – Taco zone valve

______________________________________________________________________ I have a 3 zone forced hot water, each zone valve (Taco) connected to thermostat for each of 3 zones. One zone will not stay open consistently when t-stat is calling for heat. Tried replacing t-stat, same result. If I open the zone valve manually, that zone gets heat so the path is OK. So, in bad zone, if stat is at 68 and temp is low, it calls for heat, which kicks on for maybe 5 mins, then zone closes again and radiators go cold. If I go open valve manually, heat is OK. How do I figure out if the zone valve is bad, or if the wiring to the zone valve is bad? Thanks in advance Replies: Xenos Webmaster “Re(1):One zone not opening – Taco zone valve” , posted Wed 3 Dec 17:57 ______________________________________________________________________ Actually the first thing I would be checking is the heat anticipator setting on the thermostat. Factory setup is normally .4 and your valve maybe drawing more current then .4 amps resulting in the thermostats anticipator ( internal heater) overheating and shutting the thermostat off. Xenos. The best way to escape a problem is to solve it. divjeetpatel “Re(2):One zone not opening – Taco zone valve” , posted Wed 3 Dec 21:35: ______________________________________________________________________ Thanks for the feedback…I have a Lux tx500 and I’m not sure where I find such a setting. Can you help me with this particular thermostat and how it relates to “heat anticipator”? Boiler is gas fired Burnham and thermostats/valves/boiler are 4 years old. Thanks again [this message was edited by divjeetpatel on Wed 3 Dec 21:40] Xenos Webmaster “Re(3):One zone not opening – Taco zone valve” , posted Wed 3 Dec 21:47 ______________________________________________________________________ Its ok since its a programmable thermostat. Ok remove the thermostat and Jump r and W and see if the valve properly. Xenos. The best way to escape a problem is to solve it. divjeetpatel “Re(4):One zone not opening – Taco zone valve” , posted Wed 3 Dec 22:27 ______________________________________________________________________ By jump R and W, do you mean hold red/white wires together as they come from the wall and see if heat stays on? Sorry for my novice questions… Xenos Webmaster “Re(5):One zone not opening – Taco zone valve” , posted Wed 3 Dec 22:33 ______________________________________________________________________ If there is only 2 wires then yes. Xenos. The best way to escape a problem is to solve it. divjeetpatel “Re(6):One zone not opening – Taco zone valve” , posted Thu 4 Dec 12:10 ______________________________________________________________________ Great, I will test that. If the valve does not stay open, does that point to wiring or valve? And if it does stay open, I assume that points to thermostat (even though I already tried a different one)? Xenos Webmaster “Re(7):One zone not opening – Taco zone valve” , posted Thu 4 Dec 19:39 ______________________________________________________________________ Youve got it. The best way to start is the process of elimination without replacing parts. Xenos. The best way to escape a problem is to solve it. divjeetpatel “Re(8):One zone not opening – Taco zone valve” , posted Sat 6 Dec 05:54: ______________________________________________________________________ If I jump the two wires, the valve opens initially but closes after a few minutes, just like with the t-stat connected. How do I tell if it is wiring or valve…or does this mean it is definitely the valve? When I have the t-stat connected, and it is calling for heat, the response is sporadic. Heat for 15 mins, then off. Maybe 20 minute pause…then more heat, even though the whole time, the temp is under the desired setting. Not sure why the valve would open/close like that. Other two zones working fine…heat on constant until desired temp reached. Thanks [this message was edited by divjeetpatel on Sat 6 Dec 05:58] xenos Webmaster “Re(9):One zone not opening – Taco zone valve” , posted Sat 6 Dec 10:55 ______________________________________________________________________ It really seams like the valve however its quite strange. I have never seen one act like this. There are 2 designs one is open clockwise and close counter clockwise. The other opens and closes both clockwise. I have seen a similar problem with this second one. Do you have a meter to prove power is not being disconnected? Actually this should be simple it must be the valve. Xenos. The best way to escape a problem is to solve it. divjeetpatel “Re(10):One zone not opening – Taco zone valve” , posted Sat 6 Dec 13:45 ______________________________________________________________________ I have a meter, and there are 3 terminals on the top of the valve (Taco 571), but I’m not sure which two terminals I need to check across to see if there isn’t proper voltage there when t-stat is calling. All 3 terminals have wires connected because the 3 valves seem to be wired in parallel (or series…I just know they’re connected). Thanks xenos Webmaster “Re(2):Re(10):One zone not opening – Taco zone” , posted Sat 6 Dec 15:00 ______________________________________________________________________ I just found this. http://www.houseneeds.com/shop/HeatingProducts/HydronicHeating/taco/ta cowrininpopup.htm Xenos. The best way to escape a problem is to solve it. divjeetpatel “Re(3):Re(10):One zone not opening – Taco zone” , posted Wed 10 Dec 14:12 ______________________________________________________________________ Xenos, Thanks for all your help on this. For anyone coming across this with a similar problem: replacing the power head on the Taco 571 solved it. Apparently the power head was faulty and was not keeping the valve open as it should have.

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