Water Hammer Help

[Dmgoetz23]

Hello team,
I need some help. I have pretty bad Water Hammer in my 04 Itasca Meridian 36G. I have read a lot of posts and made quite a few adjustments without solving the issue (see below list).

I feel my issue is with Air in the line. On the tank side of pump I can see air bubbles consistently in the line as it flows towards the pump

Any thoughts on what else I should try? Thank you

Things I’ve already done:
- Replaced City Water Valve
- Replace City Fill Valve
- Added soft tubing on both sides of pump
- Added Hammer Arrestor in line after pump

[Morich]

I would first have to ask more about the air bubbles in the line. There should be no bubbles big enough to see coming out of the fresh water holding tank and going to the pump. Nor should there be bubbles of that size coming from a water supply line/ faucet.
So where does the air get in?
Water coming from a tap should have pressure and water coming OUT, not letting air in.
Is it even theoretically possible for the small pump to be drawing enough pressure to make air go in without there being a pretty big leak when the pump is off? Not sure I can see that, so one other thought might/could/maybe be possible.
Is it possible for the water pumped from the tank is very low, so that the intake is drawing water and air at the same time?
Sounds like you have fought this long enough for none of these to be true, so give us more info on when and how it happens and how long it has been going on.
Is it possible to point to a place in the line that is moving and bumping into framing, etc. ?

[Dmgoetz23]

Thanks for replying Morich. It isn’t the low fresh water level as you figured.

I haven’t been able to pin point what line is truly moving, seems like the noise comes from everywhere.

The air bubbles are decent size, maybe a little smaller than a dime and occur every 6 to 12 inches.

You did give me an idea to isolate the water coming into the pump. This weekend I’ll bypass everything before the pump and run a line from a water bucket directly to the pump. This will at least show it is something causing before the pump.

[Morich]

Originally Posted by Dmgoetz23

Thanks for replying Morich. It isn’t the low fresh water level as you figured.

I haven’t been able to pin point what line is truly moving, seems like the noise comes from everywhere.

The air bubbles are decent size, maybe a little smaller than a dime and occur every 6 to 12 inches.

You did give me an idea to isolate the water coming into the pump. This weekend I’ll bypass everything before the pump and run a line from a water bucket directly to the pump. This will at least show it is something causing before the pump.

This seems like a pretty good shot at telling something. Do you have a suction line at or near the pump, designed for adding pink antifreeze? That might be possible to extend to a five gallon or so bucket to give more time to see what happens if it is not drawing from the freshwater tank.
Some water that has just been pumped or filled can contain air but that air would be expected to gas off pretty quick when setting in a holding tank. Not something I've run into but read about when dealing with tropical fish tanks.

[powercat_ras]

Because when the pump is running it pulls a suction (negative pressure) to draw the water into the pump it is totally possible to draw in air even though the line from the water pump inlet to the tank seems water tight. I had this on a former Travel Trailer I owned and resolved it by tightening everything between the pump inlet and the water tank until it resolved.

I also found that my water system worked a lot better with a $ 35 SHURFLO 182-200 Pressure Tank installed on the outlet side of the water pump, it reduces pump cycling and smoothes water faucet pulsing.

[Dmgoetz23]

Ok. So I started isolating different areas of my system and when isolating one area the noise changed dramatically and was coming from the water heater. I removed the check valve from the heater and the Water Hammering was gone. Now today I plan to put in the new Check valve and put the system back together, fingers crossed this fixes my issue.

[jerrybb]

It could be a check valve near the water heater, you'll find out. Air in the lines don't cause a hammer, they just make spurts and sputters at the faucets. I think I'd drain the hw heater completely, open the relief valve to let air into it, then fill again. I think you'll see a difference.

[Dmgoetz23]

Replacing the hw heater check valve fixed my issue. Wasn’t as tough a job as I expected, I should have replaced this sooner. All fixed.