From the very first day we purchased our RV, the plumbing sounded like someone is running a jack hammer inside the RV when the water pump was on.
Occasionally when we parked the RV just right, the sound was almost bearable. That made me think that the PEX lines must be laying against a wall causing that terrible thumping sound.
I don't think I have mentioned it before, but I HATE PLUMBING!!!
So the last thing I wanted to do was to break into the PEX water lines.
I tried several things to try to quieten that terrible noise:
I placed soft foam all around the pump. No help.
I placed foam insulation tubes around as many of the PEX lines as I could reach. No help.
I used "Great Stuff" (low expansion) foam in areas that I could reach. No help.
I even drilled small holes in the back of the shower wall to shoot the Great Stuff in to that cavity. That helped a bit but was not a fix. This is where I found that the wall of the shower is not secured to the thin material behind the shower. Sometimes there is a small gap, sometimes the shower wall is touching that backing - depending on how the RV is sitting. AhhhHaaa.
The shower wall is actually acting like a speaker which seems to amplify the sound coming from the PEX lines.
So, adding a few more plastic plugs along with the Great Stuff, the noise quietened down maybe 10%.
After consulting with one of the RV experts on this Forum, I decided it was time to address the pump issue head on. I thought about just having the pump replaced. But, the 4 chambered ARTIS pump seems like it should be as quiet as the other pumps advertised.
So, I pulled up the ARTIS water pump specifications.
STEP #1 - Use flexible hose (preferable braided or reinforced) to reduce the vibration through the plumbing system. AhhhHaaaa. Seems someone missed "STEP #1" at the factory.
Note picture showing pump with PEX lines hooked directly to it. Also note that the input filter is turned directly toward the fresh water tank. Pretty much makes checking that filter a real chore.
Soooo:
I purchased 7' of 120 PSI flexible hose and some fittings and started in. I decided to use 3 1/2 ft of hose at the input and at the output. This allowed me to make two coils.
I removed the filter and it's fixtures. Then rotated the pump filter 90 degrees - which allowed me to hook one end of the flexible hose to the bottom of the filter - pointing toward the inside of the RV. I placed a 90 degree elbow at the input of the pump and was able to hook the other end of the flexible hose to that elbow.
I loosened the output PEX line and moved it to the side. I was then able to hook up the flexible hose directly to the pump output, and with two coils, hooked the other end directly to the PEX output line/fixture.
No factory installed PEX lines had to be cut.
I placed soft foam between the coils of the flexible lines to quieten down the squeaks when the flex lines touch.
Now the water lines sound like a quiet knock with a small rubber mallet. We can still hear the motor when it's running. But at least 90% quieter than before.
As the Forum expert said, "it looks like a snakes nest, but if it works, no problem."
One little issue came up while we were in Colorado. The fresh water tank was near empty. I filled the tank with fresh COLD Colorado water. When the water pump was turned on, the pounding was back!
That night, I had one of those AhhhhHaaaa moments.
The cold water was making the flexible hoses about as stiff as the PEX lines. After a few hours, the water warmed up a bit and the loud pounding went away.
Oh, and I have no leaks.