Hi All, We have a 2015 Fleetwood Discovery with a really strange problem. Whenever we run hot water from any of the taps in the MH the water system makes a whining noise. It is loudest in the rear of the MH when taking a shower, in the rear bathroom. This is also where the water heater is located behind a wall in the rear. Another fact, it doesn't matter if the hot water heater is in gas, electric or even "off" mode, the pipes still whine. We recently had the water heater replaced due to other issues and I thought this might fix it, but no. The check valve was also replaced on the water heater as well when the work was done. This noise does not occur when running cold water, and yes the winter bypass valve is set correctly. Has anyone ever seen this? Looking for a fix! Thx, Jeff

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

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

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..

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

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.

Hot water pipes whine | Good Sam Community

20 Replies

janstey58
Explorer
Jun 15, 2017
Thx et2, DW and I have decided to live with it.
et2
Explorer
Jun 14, 2017
janstey58 wrote:
et2, I have a brand new mixing valve, water heater and check valve. Also no flow issues. No need to change these parts, but still have the noise.

Yep you're going to. I always have. New or not. Bypassing the mixer valve will fix that. But your water is going to be scalding. I've just let it be my alarm clock in the morning when my wife takes her shower :B
janstey58
Explorer
Jun 14, 2017
et2, I have a brand new mixing valve, water heater and check valve. Also no flow issues. No need to change these parts, but still have the noise.
et2
Explorer
Jun 13, 2017
The mixing valve is about $280 plus labor cost. Mine was around $500 installed. If you can do it yourself money saved, but most likely you'll have to at least partially remove the water heater to get at it.

Some say you can pick one up at Home Depot for less. You just need to assure the fittings are the same.

But ... Be warned ... It will still - always - have a whine most likely. Ours have. This new one does too. If you have no hot water or the flow is minimal it's a sign it's starting to clog. They claim it can be removed and cleaned if you're so inclined.
janstey58
Explorer
Jun 13, 2017
Yup that is it, I was told it was near $1K to replace + lots of labor.

I am guessing that I have plastic inside my plastic piping acting as a reed at this point, as everything else is new. Bummed....
Old-Biscuit
Explorer III
Jun 13, 2017
janstey58 wrote:
I found out from Fleetwood that my WH is an Atwood 94025/GE 16Ext. From online documentation and pictures, I can see that the check and mixing valves appear to be included with a new WH. I cam contacting Atwood to get their take on this.

OK now,......that is an XT model.
Uses a 160*F t-stat so the 10 gallons are heated to high temp
Then on WH Tank out let is a 'mixing valve' that has a cold water input to mix the HOT water with so the water going out into the hit water plumbing system is controlled at 130*F

Mixing valve can get clogged on hot inlet side from calcium/crud from WH tank especially if water supply source is 'HARD'

OEM mixing valves are 'sealed' and 'locked' so adjustments can nit easily be made.
They also are high priced.....Atwood #90029

Very few RV Mfgs install check valves on Cold Inlet,......very common on hot out.
Winnebago likes to do it on both
janstey58
Explorer
Jun 13, 2017
Atwood says the new unit comes with the mixing and check valve, so I am really at a loss now on what would be causing this, aside from a factory defect on the new WH.
Mile_High
Explorer
Jun 13, 2017
Even if it did come with the heater I would replace it. It may be bad new. They are not expensive.
janstey58
Explorer
Jun 13, 2017
I found out from Fleetwood that my WH is an Atwood 94025/GE 16Ext. From online documentation and pictures, I can see that the check and mixing valves appear to be included with a new WH. I cam contacting Atwood to get their take on this.
Mile_High
Explorer
Jun 13, 2017
janstey58 wrote:
However, the WH was recently replaced and it came with a new check valve per the CW repair tech

First potential false assumption :)

CW tech said a lot of things were done to mine. Once I figured out he liked to talk more than fix, I was able to erase any assumptions about what he did and start over to resolve some issues. Even basic things like - "Your rig was serviced and a new oil change tag is in the window". The oil change tag was correct, the rest was a lie.

Forum Discussion

Hot water pipes whine

20 Replies

About Motorhome Group

Related Content

Water Pump

Broken black water pipe

Will pipes freeze overnight?

Reroute Lot Sewer Pipes

Water Heater Replacement Recommendations