Hot water heater making a humming noise

[mga60tw]

My hot water heater is making a humming noise when I turn on the hot water faucet. It doesn't matter which hot water faucet I turn on. The cold water faucets do not cause the hot water heater to make the noise. It started doing this when the park lost water for almost a day. I have the hot water heater on electric. When I turn it off the electirc it still makes the same noise. I have plenty of hot water and it is just as hot as before, no differnece. I have checked the pressure relief valve and it seems to be fine. Any ideas?

[rgrstndgby]

mga60,

This is generally regarded as a sign of a pending failure of the check valve, and probably correctly so....however, mine "buzzed" all last summer without failing. When I got home and removed the valve, I found a few pieces from a valve that failed a few years ago, stuck into the ilnlet side. Removing them fixed the buzz.The valve has performed flawlessly for 6 months now, SO..., Failure isn't automatic, but I'd recommend a look see, if no debris, then I'd say, replace it. If you can find a good one, one with steel "insides" I'd say, replace it , debris or not...rgr...

[mga60tw]

are you talking about the pressure relief valve? if not where do I find the check valve?

Thanks Tom

[Martind4]

The check valve is usually found on the backside of the WH on the Hot outlet. It's purpose is to prevent backflow into the WH when winterizing with antifreeze.

If you replace it, get a brass one, plastic ones don't hold up well.