Welcome! Here are the website rules, as well as some tips for using this forum.
If you've found help here, check back in to let us know how everything worked out.
It's a great way to thank those who helped you.
1 T-sat controls 3 zone valves - please help
I found this discussion but it didn't help my situation:https://forum.heatinghelp.com/discussion/164639/1-t-sat-3-zone-valves
What I have is a house built in 1952. I purchased in 2017. It's has baseboard water heat with boiler. The boiler has a side-arm providing hot water to the house. The system has 3 zones + side-arm. The house is 650 sq. ft. above ground and 600 sq. ft. basement. 2 zones provide heat to the main house and 1 zone provides the basement. There's only one thermostat. It worked fine for about a year. Then it started not turning off a zone. That zone that didn't turn off would be over 80 degrees while the other zones turned off as expected. It's not always the same zone that won't turn off. It's annoying, concerning, and costly.
I'm not sure where/how to troubleshoot. After reading the post referenced above I'm thinking may be the thermostat doesn't have enough power/juice to operate all 3 zone valves at once. Should I just change the thermostat and see what happens - step 1 in troubleshooting? Am I making sense? Any suggestions on how to remedy?
Here are some pics which will hopefully help. 1 of the thermostat. 1 of the zone valves. and 1 of the back side of the zone valves where the wiring exists.