Problem with Honeywell hydronic zone valve--replacement the only option?
I am having problems getting hydronic heat to the basement. I checked the thermostat and transformer, which are both good. I put the lever into the Manual Open position for a couple days and got heat to the basement, but with no thermostat control. So, I looked into the Honeywell zone valve. I moved the Manual- Auto lever to the manual open position, and it returns to a center position when released. It never returns to the Auto position, and has no tension between the Auto position and about the center of its travel. The wiring for the motor looks like it's burned, so I'm pretty sure it needs to be replaced.
The real problem, though, is the lever and the valve opening gear. After I removed the motor, I can see the gear/lever and the boiler activation switch. When I move the lever to the Manual Open position, it is nowhere near engaging the switch to start the boiler. And, as mentioned, when it's not in the Manual Open position, it does not return to the Auto position. It stops about mid way.
Since the gear/lever will not move far enough to activate the switch, I doubt that replacing the motor will solve all the problems. I can't identify the valve, other than saying it's a Honeywell. No marking on the outside. Only a paper on the inside saying "motorized valve" and showing a simple schematic and switch rating numbers. It's a 24vac unit, with 2 yellow wires to the motor and 2 red wires to the switch, so it's probably an 8043 (or, more likely, an earlier version, since the install was in 1985-6). I don't know if the system has to be drained to replace the valve, or not, and I'm certainly not going to try taking it apart until the weather is warm and I can afford to drain the system if required.
Is there a way to adjust the gear/lever? Or am I doomed to replacing the whole valve?
Thanks for the help,