Hot water pipes whine

I have a single valve winterization system, so I know I have at least one check valve on the water heater. However, the WH was recently replaced and it came with a new check valve per the CW repair tech. Thinking it is highly unlikely that this is the issue.

My question is whether a replacement WH would come with a new mixing valve that I keep reading about on the these WH that "ghost" 16 gallons (really a 10 gal tank)? I have read these mixing valves can crude up and make noise or cause lower hot water temps. Does anyone know if the mixing valve typically comes with a replacement WH?

Thx, Jeff

Though I have never heard that specific complaint before I suspect it is more common than you like. I have heard of water "Whine:" on all water flow and I know what causes that.. Check valves or Pressure regulators.

A Spring check valve and a pressure regulator both have a lot in common. WIth a spring check a fairly mild (Weak, light weight) spring holds a valve closed the pressure of inconming water pushes it open... But unless you are at full flow it may close again as pressure in the lines beyond it builds up. if the spring is a bit stronger than it needs to be you will be vibration as the valve opens and closes.

A pressure regulator is DESIGNED to work like that. With water pressure in the line working AGAINST the spring to close the valve. So it can be more prounced.


Now this applies to all the water on many RV's but your problem is speific to hot water.

Many water heaters have spring check valves on the outlet, some also on the inlet. So that is my #1 (And 2) Suspets on your system.. An outlet check is needed if you have a Single valve bypass system.

It is not needed with a 3-valve bypass system.

Old-Biscuit wrote:

rv2go wrote:
It may be possible that you have 2 check valves.
When I heard that whine when using hot water, I replaced the check valve at the water heater.
Still had the whine.
Called Winnebago and was told there was a 2nd check valve and was told where it was located. Of course it was an arms length to reach. I got it out and removed the broke plunger and reinstalled it.
No more whine..

Could be a check valve on cold inlet fitting at WH Tank

But thought that was a 'Winnebago' thing ---for some reason they think it is necessary
It ain't :B

I believe it is necessary if you want to use the HW heater bypass (as one convenient valve) to winterize. If you install a valve in place of the check valve, then you don't need the check valve.

It's definitely not a Winnebago thing - every 5er we ever owned had the same check valve and they all hummed eventually and had to be replaced.

Ok, so I put the water system into "bypass" and there is no whine noise when running the hot water faucets. Also, where would the mixing valve be? Thx, Jeff

et2 wrote:
Classic mixer valve whine. Ours has always done it. Actually we're on our third as they get clogged up pretty easily from water deposits. When the flow gets less, they're on there way out.

Just had it put in last week - whines too, but we have hot water now.

IF OP has an Atwood XT model....could be the mixing valve ---IF XT Model

Classic mixer valve whine. Ours has always done it. Actually we're on our third as they get clogged up pretty easily from water deposits. When the flow gets less, they're on there way out.

Just had it put in last week - whines too, but we have hot water now.

rv2go wrote:
It may be possible that you have 2 check valves.
When I heard that whine when using hot water, I replaced the check valve at the water heater.
Still had the whine.
Called Winnebago and was told there was a 2nd check valve and was told where it was located. Of course it was an arms length to reach. I got it out and removed the broke plunger and reinstalled it.
No more whine..

Could be a check valve on cold inlet fitting at WH Tank

But thought that was a 'Winnebago' thing ---for some reason they think it is necessary
It ain't :B

It may be possible that you have 2 check valves.
When I heard that whine when using hot water, I replaced the check valve at the water heater.
Still had the whine.
Called Winnebago and was told there was a 2nd check valve and was told where it was located. Of course it was an arms length to reach. I got it out and removed the broke plunger and reinstalled it.
No more whine..

I'll try that when I get home tonight, thx!

Although you have replaced water heater (????) and the check valve it still sounds like the check valve in hot out fitting on WH is cause of 'whine'
They are cheap junk..........plastic plunger/spring/o-ring assembly that will chatter/whine when clogging/failing

Have you tried 'bypassing' WH and see if you still have noise?