This summer I had a new Trane HP and air handler installed along with an Aquecoil installed in the air handler to provide backup/emergency heat. During initial install the installer did not install check valves in the hot water in side of the Aquecoil. This of course caused thermosyphoning off of the water heater whenever the ac kicked on and blew cold air over the coil. A quick call to the install co and they promptly rectified the issue using an electric "zone valve".(if I have my terminology correct)

During the testing of the system after the valve install, all was fine. Since then I have turned the heat up to take the chill off and the em heat has come on ( 2 or 3 times) because of the amount above the room temp I kicked it up to I suppose. At any rate, when the em heat comes on, about 50% of the time we hear an annoying noise from the valve I assume, sounding like a high pitched hum as though there is restricted flow.

1) is the hum common among these electrically controled valves?

2) is there a way to view externally if the valve is running its full range of operation such as a vlave stem or piston or actuator lever?

I plan on calling the installing company but would like to have some info before doing so, so I don't burn up a vacation day for nothing!

Thanks in advance!