I just bought a house that was built in 1993 and has a gas fired Weil Mclain furnace, forced hot water, with 4 zones - each with a Taco Zone Valve. The system also has one circulator pump.
In late fall, I ran the system and all zones worked fine.
When winter came and system was on 'full time', it worked fine as well... now 1 zone is not working. I was told by previous owner that the Taco Zone Valve powerhead's "go" or fail on occasion so I replaced the suspected one last night. That zone still isn't working.
What can I do next ?