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spencerin
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# Posted: 14 Jul 2023 16:16
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I have an RV water pump hooked up to the main line maybe 6' downstream from the water heater. Given the pump's proximity the rest of the plumbing, the plumbing is fairly noisy when the pump runs. I do have a 0.75L accumulator tank hooked up to the pump, and flexible hose connecting the accumulator tank to the pex plumbing. But, it doesn't seem to dampen the noise much.
I'm thinking about replacing the accumulator tank with a 5-gal pressure tank, but I'm wondering, in your experience, will that be ineffective at dampening the noise? What about also adding a much longer length of hose?
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ICC
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# Posted: 14 Jul 2023 18:01 - Edited by: ICC
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A larger pressure tank will increase the interval between pump runs. When the pump runs it will run longer and make the same amount of noise.
Braided flex hoses used to connect the pump inlet and outlet to the plumbing pipes/tubing reduce noise but do not eliminate noise. Is your pump fixed to whatever it is sitting on or sitting loose? Screwed down with the vibration reducing grommets? Sometimes a thick foam rubber pad under the pump helps. The screws holding the pump in place should not be tightened so tight to compress the grommets or pad.
I use 16" connector flex hoses with a loop between pipe and pump.
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Nobadays
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# Posted: 14 Jul 2023 22:23
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I used Flexzilla hoses to connect my pump to the cabin plumbing via PEX. The Flexzilla are super limber and absorb much of the vibration. As ICC points out, vibration of the pump will transmit through your structure if it is mounted to a post or floor joist. Our under cabin pump is almost completely silent.... in it's own box, set on the ground (actually on a heavy tarp) beside the tanks.
Yes, a larger accumulated tank only increases pump time off and on.
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spencerin
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# Posted: 15 Jul 2023 10:53
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The pump is not connected to the cabin, so the sound is transmitting mostly though the water itself.
I thought maybe a larger pressure tank could absorb the sound better. But, it also makes sense it wouldn't as water transmits sound well.
In reality the sound is just a nuisance, but it would be nice to minimize the sound as much as possible. Thanks for the feedback.
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ICC
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# Posted: 15 Jul 2023 13:44
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There is one thing I like about hearing the pump. If a faucet is not turned off fully or there is a leak the pump will run and the noise signifies there is an issue.
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Brettny
Member
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# Posted: 15 Jul 2023 21:36
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Is it the pump noise or the water hammer effect your hearing of the pump cycling?
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spencerin
Member
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# Posted: 15 Jul 2023 23:04
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Pump noise.
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Brettny
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# Posted: 16 Jul 2023 06:13
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You just need to move the pump further away then.
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Grizzlyman
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# Posted: 16 Jul 2023 21:43
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I actually just encountered this rv pump noise problem this weekend… so I’m following to see what you come up with. To be fair, I did mount the pump to the beams that support the cabin- I figured some vibration would happen, but it is louder than I’d like. Sometimes you can’t really hear it, and sometimes you can- really just depend on how quiet it is outside at the moment. The one nice thing is you can tell when it’s working.
I tried mounting to a 2†piece of pink foam insulation but that didn’t seem to make all that much difference.
2 options I’m considering is moving it off the cabin entirely, and/or looking into anti-vibration bases/pads.
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travellerw
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# Posted: 17 Jul 2023 10:25 - Edited by: travellerw
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Quoting: Grizzlyman 2 options I’m considering is moving it off the cabin entirely, and/or looking into anti-vibration bases/pads.
A common solution used by RVers is a DIY vibration pad. Essentially 2 pieces of plywood with soft foam (like mattress foam) glued between them. Make the bottom piece of ply larger so you can screw it down, then screw the pump to the top piece. The picture should make it clear.
Second, you NEED to change how the pump is connected. That PEX will transmit a ton of noise and vibration. Amazon sells pump silencer kits (just flexible hoses) that people use. Make a HUGE difference.
Third.. Where the pex is running along the joist, I would put it in pipe insulation and not have it in direct contact with the wood. Instead of those nice plastic clips to secure it, just use zip ties with a screw hole.
With those 3 things done, you will struggle to hear it.
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Grizzlyman
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# Posted: 17 Jul 2023 12:23
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travellerw
Thanks- Very helpful
Sorry to the OP- not trying to Hijack thread, but feel it is in the same vein.
No PEX- its Vinyl tubing. I didn't have the tubing attached to the frame at all at first and noise was the same... noise hasn't changed with the addition of fastening tubing to structure. .
I will definitely start with the pad and look into hoses- they seem to be more or less the same hoses as like a toilet or washing machine??? . I'm guess the flexibility of these hoses dampen the vibration so that its gone by the time it reaches the PEX or other semi-rigid tubing...I would think 100% nylon tubing would kill the vibration the same as these do ? ... but will definitely check it out- Thanks again
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spencerin
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# Posted: 19 Jul 2023 13:20 - Edited by: spencerin
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I have a 20" run of the braided flex tubing from the accumulator tank to the pex right now. Maybe I will install a full 10' segment instead, see how that works. I don't mind some sound, but this is loud enough to be a minor nuisance.
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travellerw
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# Posted: 19 Jul 2023 14:58
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Quoting: spencerin I don't mind some sound, but this is loud enough to be a minor nuisance.
Is your pressure tank hard mounted against anything. I had noise in my trailer when my tank was hard mounted to the wall with a strap. The pump pulsing was being transmitted through the tank and into the wall.
No matter what size of tank I couldn't get rid of all the noise though. There are parts of the trailer where the PEX was run through walls and there would be noise transmitted through the PEX and into the walls.
At one point I even considered trying an impeller based pump to remove the pulsing. Instead I just decided to drink enough beer that it stopped bothering me! ;)
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spencerin
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# Posted: 19 Jul 2023 15:48
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Nope, it's free-floating on the ground.
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