I have a General Controls Zon-Val zone valve -24VAC-1.2a. The thermostat energizes a coil which heats up and forces a plunger into a contact assembly to operate the gas valve and circulator motor. The plunger rod has been sticking lately causing erratic timing of the heating cycle or no operation at all. Can I use a lubricant on the plunger like an antisieze compound? I tried to find the manufacturer (General Fittings Corp.) to no avail. Thanks for help.
When I worked on elevator holding contactors and controllers and other electronic devices as a stationary engineer I found WD 40 could ruin certain seals. You could try some of the silicon /Teflon sprays out there that wont affect the seal (rubber).
Try one valve and wait a few days before you spray all the others. Good luck