two of my zone valves have rust on them. Do I need to replace them?
two of my 5 zone valves have rust on them. I do not see any active dripping and the manual open/close works easily (which means that they're open, right?) What is causing this rust? Should I replace them now before the dead of winter comes? I just bought this place and the boiler seemed to be neglected. My contractor said he can get rebuilt ones for $50 each.
Is the rust just on the outside casing from an external source like
condensation dripping from piping above it? Do you get the heat you want through those zones?
The ability to move the activating zone lever only tells you that the zone motor or linkage is probably not seized. When the thermostat for the zone valve is off, you should feel a smooth, steady resistance to swinging over that zone valve arm. It should return to its starting position on its own.
When the thermostat is "on" the swing arm will move fully from one side to the other and can be slid back and forth with no resistance.
If the water(rust) is coming from inside the zone valve, it should be serviced.
Zone valve motors or the valve activating guts are easily replaced.
I am not sure what your contracter means by rebuilt units.