Water 'Hammering' issue

[Singleminded]

Need some help with a weird problem.....!

Background:

We're in a campground (which we've been in for the past three months) in a 2016 Winnebago TT hooked up to the 'city' water supply. We haven't changed anything in the water supply set up....(other than the filter two months ago) and do not have a pressure regulator hooked up in line. (haven't needed one....campground water pressure is very stable)

After flushing the toilet.....When we depress the foot pedal further to allow some water to build in the bowl, we get very loud 'hammering' sound from the rear (junction box, water inlet location)!

None of the other water sources (kitchen sink, bathroom sink & shower) have the same problem....when flowing water, no hammering!

Any suggestions would be appreciated!

[Gjac]

Singleminded wrote:
I promised to update....Amazon did it's usual....received the water hammer arrester same day....!

In hindsight, I should have done this in two stages, but....I bled the water lines on the exterior shower unit andand installed the arrester.....Hammering is gone!

I did have some air spitting when I bled the cold water line, so I suspect that was the culprit....but still puzzled as to why none of the other water outlets caused hammering when flowing?

Another wonderful mystery of life!

My guess would be that when filling your toilet bowl after flushing you are barely pressing down to allow water to flow in. On your other faucets you probably open them normally. When ever I encountered hammering it always occurred at very low flows once faucets was opened up the hammering went away.

[Dave_H_M]

i bet that air was more the culprit than you needing the gizmo.
My toilet acted the same as you described and i have an accumulator in the system.

Anyhow glad it is fixed and I now have something to check for the next time I am camping.

[Singleminded]

I promised to update....Amazon did it's usual....received the water hammer arrester same day....!

In hindsight, I should have done this in two stages, but....I bled the water lines on the exterior shower unit andand installed the arrester.....Hammering is gone!

I did have some air spitting when I bled the cold water line, so I suspect that was the culprit....but still puzzled as to why none of the other water outlets caused hammering when flowing?

Another wonderful mystery of life!

[myredracer]

newman fulltimer wrote:
Get a water regulator the toilet is not designed for the water pressure going to it the valve will eventually fail

Funny you say that. We discovered at the end of last season that our toilet valve leaks water into the bowl when the pressure gets low, like around 10 psi. The entire CG had gone low and we were lucky to catch it while in the TT otherwise could have done serious damage. Pressure went back up to normal and stopped leaking. Checked on the internet and found we're not alone. Installed a new valve kit and it leaked worse. :M Gotta figure it out soon before the season starts up again.

Agree on a regulator. Some have reported it as high as 200 psi. I have seen it as high as 140 psi so far. I run our Watts at 65 psi.

[wa8yxm]

The city water inlet can "Buzz" more than Hammer. I will stick with
Water flowing: you've turned on the water pump, check to insure it's off
Hammering at shut off.. See previous replies re: Arrestor

And the folks who commented on max pressure.. yes, a good regulator, not the cheap cylinderical type but a Valterra, Watts or Zurin 1/2 inch or larger (3/4 is a nice size, easy to adapt to garden hose fittings) at the park end of your hose.. Very good idea.

[Old-Biscuit]

Hammering happening AT toilet OR it is happening at city water connection?

At toilet..then too high of flow.

But if at city water connection.......check valve inside city water assembly is CHATTERING


45# pressure is NOT an issue.
Need to check flow per minute.
Get a 1 gallon jug (milk jug etc)
Measure time to fill to overflowing

Should be in the 3.5 gpm to 5 gpm

[naturist]

A "water hammer arrestor" ought to be really, really cheap. It is nothing more than a piece of capped pipe tee'd off to the side of the line in such a way as to contain a small air chamber that can absorb the shock of closing a valve in a flowing water line. For anyone needing one, buy the tee you need to install in whatever your water pipe is, an adapter to up the pipe diameter to 1 or 2 inches, a cap that size, and 2 feet of that size pipe. Should cost you less than $5 at Lowe's, HD, etc. Glue the cap on the pipe, glue on the tee, cut the line, and install with the pipe pointed up so the cap is on top. Bingo. Water hammer arrestor.

[newman_fulltime]

Singleminded wrote:

newman fulltimer wrote:
Get a water regulator the toilet is not designed for the water pressure going to it the valve will eventually fail

I have checked the Campground water pressure each month...hasn't varied by more than 4 psi from a norm of 45 psi.....but I will reinstall my P reg as a test! Thanks!

Its not only the pressure but the gallons per minute that can cause the hammering just a case of to much wster.As a test use your onboard pump and tank bet the problem goes away

[Singleminded]

newman fulltimer wrote:
Get a water regulator the toilet is not designed for the water pressure going to it the valve will eventually fail

I have checked the Campground water pressure each month...hasn't varied by more than 4 psi from a norm of 45 psi.....but I will reinstall my P reg as a test! Thanks!

[Singleminded]

wa8yxm wrote:
Ok, IN an RV there are TWO causes of "Hammering" not one like in a sticks and bricks

The first (Never heard it in my RV) is caused by the physics of what happens when you CLOSE a valve. this is called Water Hammer and the advice of the others on this issue is dead on.. The "Arrester" is nothing more than an air chamber that absorbs the Hammer.

The other source which is unique to RV's is the on-board fresh water pump.
This will HAMMER when water is flowing.. The Toilet (And Shower) are the major flow items in the RV.. So if the city water inlet is partially clogged or if the city water pressure is low or if there is any "issue" with city water that limits flow such as a aging pressure regulator.. The on board pump, if powered on (Switch is on) may engage and it can Hammer. even with flex lines to/from it it can hammer... It is, after all, a jack hammer.

A buddy mentioned the same thing about the water pump....we have not used the TT water pump at all...been on 'city' water since we hooked up months ago...I will bleed the outside shower, just in case there is an air bubble.....but why is this problem only happening when filling the bowl after flushing? That's what's puzzling me....!

[newman_fulltime]

Get a water regulator the toilet is not designed for the water pressure going to it the valve will eventually fail

[Dick_B]

In the meantime try pinching down on the valve on the post to cut down the flow. May not make a difference but there is no cost to try it.

[wa8yxm]

Ok, IN an RV there are TWO causes of "Hammering" not one like in a sticks and bricks

The first (Never heard it in my RV) is caused by the physics of what happens when you CLOSE a valve. this is called Water Hammer and the advice of the others on this issue is dead on.. The "Arrester" is nothing more than an air chamber that absorbs the Hammer.

The other source which is unique to RV's is the on-board fresh water pump.
This will HAMMER when water is flowing.. The Toilet (And Shower) are the major flow items in the RV.. So if the city water inlet is partially clogged or if the city water pressure is low or if there is any "issue" with city water that limits flow such as a aging pressure regulator.. The on board pump, if powered on (Switch is on) may engage and it can Hammer. even with flex lines to/from it it can hammer... It is, after all, a jack hammer.

[Singleminded]

Thanks all!

I've ordered a water hammer arrestor from Amazon (cheap!) with same day delivery....so it will be installed no later than late tonight....I'll report back on the results! (I'll also check for a lose clamp!)