Zone Valve Keeps Spinning

boiling4boilers

I have a boiler running 3 zones in my home.  My zone valves are White-Rodgers model # 1311-103.  They are 3-wire zone valves.  When my thermostat for the upstairs calls for heat, the zone valve continues to rotate the entire time that zone calls for heat.  When the zone reaches temperature, the valve shuts off just fine.



When no other zones are calling for heat other than the problem one, the boiler will cycle on for about 20 seconds, then cycle off for about 20 seconds, continuing until the zone reaches the correct temperature.



I recently purchased new thermostats (Honeywell FocusPro 6000) that I know work with this system.  I have 2 others that work just fine.  The wiring appears to connected correctly to the thermostats and the valves.  (the 4, 5, and 6 terminals on the zone valve match the W, Y, and Rh wires on the thermostats)



I am not 100% certain if this problem was happening before I replaced the thermostats, but I believe it was happening before.



My question is, can you tell from this if the zone valve is bad, or if there is a wiring issue with the system that is causing the valve to stay rotating?



Thanks

Charlie from wmass

Sounds like there is a switch not working in the zone

valve. you are sure you have traced the wires and checked for shorts? You could look into an outdoor reset and a variable circulator to stretch out your cycles. 20 seconds is a very short cycle.

boiling4boilers

thanks

That's what I was afraid of.  I will check the wires for shorts.  Thanks!

MikeG

Just worked on these

I just recently rewired three of these on a system in a house my son just bought.  All the wiring was disconnected and the valves were maually set to the open position with one T-stat running everything.  Now I have it back to the three zones with the three T-stats.  Currently all three T-stats are different brands, but it sounds like you have compatible T-stats for a 3 wire zone valve.  I bench tested all the motors before reinstalling them.  I attached the IO manual.  Terminal 5 is 24V from the transformer and 4 to open and 6 is to close.  It sounds like a possible internal wiring issue.  Once the valve starts to open or close a holding circuit takes hold to make the valve complete a 90 degree rotation and not stop in the middle.  If the holding circuit is not working it will continue to turn and make, then break, and make and break contact.  That means your boiler will start and stop about every 90 degreees of rotation or about every 20 seconds.  Look at the bottom where the wheel rotates to see if you see any loose wires.  Also pull off the back very gently where the wiring terminals are to see if any of the soldered leads are off the brass contacts.  I have one that I have to try and do some repair surgery on to see if it will work as a spare.  Mike