Plumbing mystery

mjones12 · 02-21-2018, 02:40 PM

Every time I flush commode (do it for 10 seconds), I hear a sound for a couple of seconds at the fresh water inlet. Sounds almost like a pump running, but we're on city water and pump is off.

Doesn't happen when I turn on any other water source. Just commode. Fresh water hose on tight. Filter in the connection is clean. Pressed check valve and it spit water on me, but that didn't fix noise.

Besides the sound, everything seems to be working normally with excellent water pressure.

Also, does not happen with short flush, just a longer one.

Any ideas?

18CrewDually · 02-21-2018, 03:23 PM

If it sounds like a pump, did you find the water pump and unplug the fuse, then try a long flush to see if the noise had stopped?

5picker · 02-21-2018, 03:45 PM

I suspect a vibrating city water check valve.

I seen one of these about 20 years ago that did the same thing.
This one did it when flushing or using both faucets (hot & cold) at the same time.

Smaller flows did not cause the noise, nor did using the on-board pump.
Have you tried the same scenario using the pump as the water source?

The inrush of flow at the check valve, caused it to vibrate.
The city water connection was replaced and all was well.

mjones12 · 02-21-2018, 03:49 PM

Quote:

Originally Posted by 05CrewDually

If it sounds like a pump, did you find the water pump and unplug the fuse, then try a long flush to see if the noise had stopped?

Good idea, but the water pump is nowhere near the source of the noise, which I really think is outside at the hose. Can't understand why other demands for water would not cause the same noise.

Can't find the fuse, but based on your idea, I will put some water in the FW tank, turn on pump and see what that sounds like when flushed. Thanks.

mjones12 · 02-22-2018, 09:04 AM

Quote:

Originally Posted by 05CrewDually

If it sounds like a pump, did you find the water pump and unplug the fuse, then try a long flush to see if the noise had stopped?

Crew Dually: after doing it for two days, the noise has stopped. Maybe some sort of water supply or pressure issue that finally resolved itself?

But I wanted to get back to you and thank you for a great idea.

mjones12 · 02-22-2018, 09:08 AM

Quote:

Originally Posted by 5picker

I suspect a vibrating city water check valve.

I seen one of these about 20 years ago that did the same thing.
This one did it when flushing or using both faucets (hot & cold) at the same time.

Smaller flows did not cause the noise, nor did using the on-board pump.
Have you tried the same scenario using the pump as the water source?

The inrush of flow at the check valve, caused it to vibrate.
The city water connection was replaced and all was well.

That is a very interesting idea. Makes sense. As the noise has now stopped, I will know where to start looking if it starts back up. Thank you.

18CrewDually · 02-22-2018, 09:10 AM

Quote:

Originally Posted by mjones12

Crew Dually: after doing it for two days, the noise has stopped. Maybe some sort of water supply or pressure issue that finally resolved itself?

But I wanted to get back to you and thank you for a great idea.

Thanks and glad it stopped. Maybe it was the checkvalve on the city water side?

mjones12 · 02-22-2018, 09:15 AM

Quote:

Originally Posted by 05CrewDually

Thanks and glad it stopped. Maybe it was the checkvalve on the city water side?

Yeah, that's what 5picker was thinking, too. I will followup with you guys if there any other developments.

So glad there are smart and helpful people on this forum. Thanks again.

18CrewDually · 02-22-2018, 09:24 AM

Now that I think about it more, on my black tank backflush hookup there is a checkvalve too. Sometimes when I use it, it will vibrate and hum so much it practically vibrate the camper. If I wasn't winterized I'd make a video for you to compare. I'm siding more with it being the checkvalve.

bubbles · 02-22-2018, 09:41 AM

Quote:

Originally Posted by 05CrewDually

Now that I think about it more, on my black tank backflush hookup there is a checkvalve too. Sometimes when I use it, it will vibrate and hum so much it practically vibrate the camper. If I wasn't winterized I'd make a video for you to compare. I'm siding more with it being the checkvalve.

Only thing is the black tank check valve is inside your RV and is also a vacuum breaker. What you hear with it is the water rushing through (cavitating). The check valve for shore water is at the input port and yeah it might have been vibrating.

Iwannacamp · 02-22-2018, 10:18 AM

I would suspect a little grit in some valve/diaphragm somewhere. My first suspicion is the pressure regulator(assuming) is/was chattering somehow. Maybe clean/flush out the regulator. YMMV

mjones12 · 02-22-2018, 10:34 AM

Thank you all. Really great input.

CedarCreekWoody · 02-22-2018, 10:57 AM

There could have been air trapped in the valve and it finally cleared.

mjones12 · 02-22-2018, 12:35 PM

Quote:

Originally Posted by CedarCreekWoody

There could have been air trapped in the valve and it finally cleared.

I think that's another good possibility. Thanks, Woody.

5picker · 02-22-2018, 07:31 PM

One final thought... are you using a pressure regulator when connected to city water? It may have been a high pressure situation causing the valve to chatter.

mjones12 · 02-22-2018, 10:12 PM

Quote:

Originally Posted by 5picker

One final thought... are you using a pressure regulator when connected to city water? It may have been a high pressure situation causing the valve to chatter.

Yes, sir. Using a 60 psi regulator, which is pretty high. Another good point.

Scrapper · 02-22-2018, 10:48 PM

My toilet flush valve vibrates if I don't push it down all the way. It sounds like the water pump is running. I know it not the pump because the only time I use it is when I winterize. I use a adjustable pressure regulator set to 45psi.

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