Water heater problem: Does this sound familiar to anyone?

[taletellers]

I have a '97 Adventurer, and started hearing a strange ratcheting, buzzing sound in the vicinity of the water heater a couple days ago. It only happens when we turn on the hot water, and doesn't appear related to ignition.
Is there a pump of some sort in the heater, or could this be some kind of airlock? I've looked in every crack and crevice I can find, and don't see anything mechanical that might be making the noise. Any suggestions would be welcome.
Thanks,
Jim

[taletellers]

I have a '97 Adventurer, and started hearing a strange ratcheting, buzzing sound in the vicinity of the water heater a couple days ago. It only happens when we turn on the hot water, and doesn't appear related to ignition.
Is there a pump of some sort in the heater, or could this be some kind of airlock? I've looked in every crack and crevice I can find, and don't see anything mechanical that might be making the noise. Any suggestions would be welcome.
Thanks,
Jim

[Trek-Cyclist]

taletellers,
Sounds like a check valve....Spring vibrating against the valve body... Sometimes if you flush the HW Heater it cures it..other times its the valve going bad. Before replacing I would give the ole' heater a good flushing...

[Izzyblueye]

Almost certainly it is a check valve problem. Will get worse then fail all together. Try the simple flush first, then think about replacing them.

[Wizard]

Yup, ours sounded like something vibrating in the water heater. Mine had 2 check valves, inlet and outlet. The are mostly for winterizing. I've heard many people take them out and toss. I preferred to keep mine stock and replaced them with valves I ordered from Tweety's. Marshall Brass valves, cost was about $5 each.

[taletellers]

Ed, Wizard and Homer.
Thanks very much. It's nice to know it's 5 dollar part. I've got the manual out now so I don't do more harm than good.
I'll let you know what happens.
-Jim