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Topic: loud banging when flushing toilet and using rear sink (Read 213 times) previous topic - next topic
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loud banging when flushing toilet and using rear sink
All,

I'm at RV shop picking up my LD. New gasket put on toilet and check valve replaced on hot water heater. However, now very loud noise and vibration when toilet or rear sink used. The guy didn't seem to think it was an issue and in fact said it's because now they work. But they both got fine water pressure before without any noise. He said I could take it on my short trip and bring back when I return but I said no way. So he's looking at it again.

Any ideas what would cause the noise and  vibration now when it wasn't there before? No issue with kitchen sink.

Lisa
1991 22' LD Multi-Plan
Re: loud banging when flushing toilet and using rear sink
Reply #1 –
Lisa,

I can’t be sure of this and perhaps others can chime in, but hadn’t you recently drained your hot water heater?

When refilling your hot water heater tank via your onboard water pump, it is important to bleed air out of the hot water heater tank as it is being filled.

This is done (No Hot Water In WH Tank) by opening the toggle on the hot water heaters pressure relief valve on the outside of the rig (remember to remove plastic plug at the pressure relief valve opening if one is in place) and then (while hot water faucets in your sinks are open) turn on the water pump and watch the hot water heater pressure relief valve  (outside the rig) until water comes out of the valves opening. Then close the toggle and turn off the water pump and sink taps.

This allows an air chamber to be present in the hot water tank. This may quiet down your pump.

If you have already done these steps then I’m not sure where your noise is coming from. Although it may just be that the toilet water lines need to feed for a while to purge air from them.

Best of luck.

Kent
2015 27' RB "MissB.Haven"
Re: loud banging when flushing toilet and using rear sink
Reply #2 –
Lisa, your issue is not likely to be from the water heater.  The toilet does not draw from that part of the system so having the issue with the toilet means the heater is probably not the cause.

Air in the system may be an issue, but if so, I would expect to have the problem in the kitchen, shower, bathroom sink and toilet - everywhere.  When I have air in the system, I would not describe it as a banging.  Rather, I hear a spitting and whooshing sound that persists in pulses for up to a minute after I first open the faucets after the air was let in, then it goes away, not to return until the next time I let air into the system.  This is called bleeding the air out of the system.  Once that is done, the only noise should be from the pump.  Now, if the pump has air in it, or if it can suck air in from a leaking strainer or intake hose connection, the pump can generate a vibrating noise that can be fairly loud.  Make sure there is plenty of water in your fresh water tank.  Open the access to the pump, then turn on the tap at the rear sink.  With the water running, return to the pump and put your hand on the side of the pump.  If the vibration you are feeling seems to match what you are hearing, and if there is no spitting at the faucet, you might have a problem with the pump.  Like Kent, I do not have any sense of certainty about the cause of what you are experiencing.  Having the issue at the toilet and rear sink, but not in the shower or kitchen does not match anything I know of that might cause noise and vibration.

I can say this with assurance - your system is not designed to generate a banging and vibration when in use.  That is NOT "how they now work", unless that service place routinely does something wrong.

Ken F in NM
'08 MB
Re: loud banging when flushing toilet and using rear sink
Reply #3 –
Well he fixed it. Turned out the replacement check valve in the HWH was causing the problem, though he doesn't know why. He swapped it out for another and it's fine now. Actually I think it may be a bit quieter than it was before. All good!

Now my hot water works as it should and my toilet doesn't leak AND it's properly bolted down. Apparently it wasn't before. Guy was like " didn't you notice the toilet moved when you used it?!" I only used it twice and just thought that was how RV toilets were!

Just typing that makes me laugh.
1991 22' LD Multi-Plan
Re: loud banging when flushing toilet and using rear sink
Reply #4 –
hmm, reading your replies I look back and recall he did drain a bunch of water from what must've been the HWH (only holding tank on right side of vehicle). So maybe it was really just draining it and restarting that fixed it and not swapping out check valve?

I had not drained the HWH. Only freshwater tank. Ran out of time.

But valve or draining or miracle, it's quiet again and I have working hot water. So hallelujah!
1991 22' LD Multi-Plan
Re: loud banging when flushing toilet and using rear sink
Reply #5 –
Lisa, I hope you are keeping a diary on your issues . You will have a wealth of reference materials for the future.
1994 MB
Re: loud banging when flushing toilet and using rear sink
Reply #6 –
Here's a similar symptom that I've experienced for years, both in my 2003 Lazy Daze and my 2017 Airstream. (Both have Shurflo 4008 water pumps.) In a nutshell, I experience loud pounding/vibrating from the water pump after traveling. It doesn't matter whether the water tank is full, half full or a quarter full. The loud noise occurs when using either faucet, the shower, or the toilet. It persists for anywhere from several hours to a day or more, then goes away.

I thought perhaps the pump was somehow partially losing its prime, but does that even make sense? When installing a new water pump, I don't remember getting long-term vibration/pounding.

Anybody else experience this? Anybody have an idea what causes it?
Andy Baird
2021 Ford Ranger towing 2019 Airstream 19CB
Previously: 1985 LD Twin/King "Gertie"; 2003 LD Midbath "Skylark"
Re: loud banging when flushing toilet and using rear sink
Reply #7 –
Andy, I do.  When I relocate, I often have a tank with half or less fresh water.  I determined some time ago that the sloshing in the tank can allow momentary air breaks at the outlet.  Air bubbles can then work up to the strainer, then into the pump when I use the pump.  Before I fitted some foam between the outfeed hose and the cabinet wall, the thumping and vibration was pretty bad.  It took about a gallon of water running through it before it would quiet down.  The lower the tank level when I would move, the louder and the longer the noise.  I ultimately determined that air in the pump was the issue, and it did not take much air to make it happen.

I thought about this for Lisa's issue, but she said it did not make noise when she used the kitchen sink, so I considered air being the cause unlikely.

Ken F in NM
'08 MB
Re: loud banging when flushing toilet and using rear sink
Reply #8 –
We had a little older Tioga MH and would hear this exact thing. The water lines would just pound when the pump was turned on. I contributed it to air in the system. We had a couple low point drains so I would open them with the pump on and things would settle down. In plumber terms, it's water hammer and when any air is gone it'll quit or the pump will cycle off, which ever comes first.

Jon....
1994 MB
Re: loud banging when flushing toilet and using rear sink
Reply #9 –
I have never experienced the 'thump and bang' issue at any water level in the tank, but the water pump in my 2003 is a Whisper King; it's the second WK installed. True, it's a bit puny, but I'm used to it! When it dies, there's a 4008 waiting in a compartment; the 4008 is the recommended replacement pump since the Whisper King is no longer manufactured. I'm curious whether others who have the 4008 have experienced 'pump shudder'?
2003 TK has a new home