*FIXED* pump water hammer with Nautilus

rhyno

We picked up our 2021 400 this morning and it seems like the pump is a lot louder than it should be. I suspected an air bubble and tried opening all faucets inside and out, flushing the toilet, opening the low point and both alde drains. While some air came out initially, nothing quieted the pump. I then tightened all of the fittings on the pump and nautilus connections, many of them a quarter turn or more and also moved all the hoses around to make sure nothing was banging on anything else. The noise seems to be coming solely from the pump. I finally tried setting the Nautilus to sanitize and winterize and drained some water from the low point and Alde drains, again no luck. Does anyone have any suggestions to try?

UPDATE - I fixed the noisy pump by twisting the strainer basket up a little higher so that it sits just a bit above the level of the water inlet line.

ChrisFix

@rhyno
The tricky part of your question is how loud is loud? The pump is definitely noticeable when working - and that is SOP as far as I know. If nothing is loose, shaking, or rattling, it may just be normal operation.

rhyno

@ChrisFix - its louder than our old RV pump by comparison so I mentioned it to the dealer during the walk-through this morning. He said it should quiet down once the air is worked out. It just hasn't calmed down as of yet.

rhyno

**Update**At this point I have now snugged up over a dozen loose plumbing connections in the Alde compartment, behind the shower, under both sinks and the toilet. Many were full turn loose and one was leaking. I refilled the tank to retry and here's where I am at this point:

1.The pump's strainer basket is attached sideways on the pump, parallel to the floor and keeps getting air bubble in it. When I shake it around and bang on it, the bubbles work out and pump runs more quietly, but the bubbles keeps coming back. Where would I be pulling air into the system from? Should the basket be pointing down so it won't retain these air bubbles so easily?

2.I seem to be stuck in a cycle where if I bang enough on the pump I can work out the air and it will run quietly while I have the galley sink running. But if I run the shower, other sink it starts acting up again and I have to shake the pump to get it to settle back down. If I flush the toilet, the noise comes back with a vengeance. For the toilet in particular,each time I flush it sounds like there is a bit of air coming out each time rather than a smooth stream of water but maybe that's a normal sound?

Dalehelman

Adding some fiberglass insulation in the area around the pump should help. RV pumps are just noisy and have been for as long as I can remember. I think there are quieter ones available but they are more expensive. 

qhumberd

rhyno said:

**Update**At this point I have now snugged up over a dozen loose plumbing connections in the Alde compartment, behind the shower, under both sinks and the toilet. Many were full turn loose and one was leaking. I refilled the tank to retry and here's where I am at this point:

1.The pump's strainer basket is attached sideways on the pump, parallel to the floor and keeps getting air bubble in it. When I shake it around and bang on it, the bubbles work out and pump runs more quietly, but the bubbles keeps coming back. Where would I be pulling air into the system from? Should the basket be pointing down so it won't retain these air bubbles so easily?

2.I seem to be stuck in a cycle where if I bang enough on the pump I can work out the air and it will run quietly while I have the galley sink running. But if I run the shower, other sink it starts acting up again and I have to shake the pump to get it to settle back down. If I flush the toilet, the noise comes back with a vengeance. For the toilet in particular,each time I flush it sounds like there is a bit of air coming out each time rather than a smooth stream of water but maybe that's a normal sound?

I think you have a connection that is before the pump that is allowing air into the system. There is no long period of "air working itself out". It is a simple pressurized plumbing system not that different from household plumbing. When you drain the lines there is air and when you reconnect to water or fill your tank that amount of air should be gone in a few seconds. I recall a thread here about a small crack in the strainer causing air entry and another small kink in the line from the inlet from the water tank.

https://tab-rv.vanillacommunity.com/discussion/5588/pump-problems/p1

If you are seeing bubbles in the strainer, then you have a leak prior to that point and there are not that many connections from there to the fresh water tank. 

Also if you have not connect to city water and see if there is prolonged sputtering of air and open all the lines to clear them, then try the pump again with city water off.