Noise when Hot Water is turned on

[dlvgolf]

We’ve been living in RV FT since Nov 2019. Yesterday out of the blue, when the hot water is turned on, there’s a whining sound that seems to be coming from the hot water heater. It only makes the noise when the hot water is turned on. No noise when it’s just cold water. It happens no matter which faucet you turn on, bath room, kitchen, outside. I thought maybe air in the lines, so I drained the hot water heater. No change. Any ideas, thoughts suggestions?
Thanks, Dave

[Lt Dan]

More than likely it's the one way check valve on the back of the water heater. These are know to vibrate when water is flowing.

[Old-Biscuit]

YEP^^^^^


Water Heater HOT Out 'check valve' is failing
It is a cheap plastic plunger/spring/o-ring assembly in the 'nipple' screwed into WH Tank


**Winnebago sometimes uses TWO.....one in Hot Out and also one in COLD Inlet (either could cause the noise but typically Hot Out)


Scale/calicum build up, o-ring gets dislodged, spring weakens etc.
Replace it (water supply OFF, pressure relieved, unscrew hot water line fitting, unscrew nipple----replace with new then connect hot water line)
Or wait until it blocks hot water flow completely --- usually when on a camping trip


Check valves are used instead of shutoff valve because they are cheaper/less labor and can be installed in water heater prior to installation in RV


Check valves are used for 'winterizing' ------prevents backflow thru hot out when WH Tank is Bypassed



I prefer a Hot shutoff valve vs those cheap check valves


Example of water heater plumbing using a check valve

[dlvgolf]

Originally Posted by Lt Dan

More than likely it's the one way check valve on the back of the water heater. These are know to vibrate when water is flowing.

Found them. Thank you.

[l1v3fr33ord1]

The Atwood water heater on our coach makes a high-pitched sound when the electric element is on. You could call it a "whine." It is faint.

And, the water heater has no check valves, I having removed them and converted to a three-valve system.

[imnprsd]

I prefer no check valves at all! I spent 3 days taking cold showers while I was trying to find a shop (on the road) who would replace my OEM check valve without success -- and then I took matters in my own hands.

... My recommendation is to leave the check valve in place and drill it out if you have room for a drill. If not you will need to remove the check valve with a big 1-1/8" (?) wrench so you have enough leverage ...a large crescent wrench may not provide. (TBD)

... Drill and remove the check valve guts to turn the check valve into a nipple

... Reattach the PVC with a new donut inside you can get at any trailer/RV shop (Just 50-cents so I recommend buy a couple extra.)

... Use Teflon tape and do not over tighten the PVC.

NOTE: Most people don't have that much space behind their Hot Water Hear to work with.

[dlvgolf]

This is what I found. I can only access it through an opening when I pull out a small drawer. I have an RV service center down the street, so I should be able to get a replacement valve. Does the process go like this: Turn off water, turn off and drain hot water heater, put big wrench on valve and unscrew it from tank. Teflon tape new one and screw it in. Turn everything back on and hope that nothing leaks. Did I miss anything?

[KanzKran]

Originally Posted by dlvgolf

. . . put big wrench on valve and unscrew it from tank.

Two big wrenches, as it may take some wellie to get it off. Or not. But if it does, you may damage the tank or fitting if you don't put a wrench in that inner hex.

[Old-Biscuit]

Originally Posted by imnprsd

I prefer no check valves at all! I spent 3 days taking cold showers while I was trying to find a shop (on the road) who would replace my OEM check valve without success -- and then I took matters in my own hands.

... My recommendation is to leave the check valve in place and drill it out if you have room for a drill. If not you will need to remove the check valve with a big 1-1/8" (?) wrench so you have enough leverage ...a large crescent wrench may not provide. (TBD)

... Drill and remove the check valve guts to turn the check valve into a nipple

... Reattach the PVC with a new donut inside you can get at any trailer/RV shop (Just 50-cents so I recommend buy a couple extra.)

... Use Teflon tape and do not over tighten the PVC.

NOTE: Most people don't have that much space behind their Hot Water Hear to work with.

No need to do any drilling


Remove check valve
On tank side of nipple is a small plastic clip oin end of plunger
Needle nose pliers...remove clip then push plunger/spring out the other end of nipple.

[dlvgolf]

Changed out hot water valve. Noise went away. Thanks everyone.

[lockinload]

I just replace mine too, sucker sang like a song bird. Will now in a day or so if the problem is fixed. Good thread, thanks for the fix gentlemen.