Hunter 340 noisy water supply system.

[Robert1224]

Ahoy,
I was on a friends Hunter 340 trying to help determine the source of noise and vibration in his fresh water supply. I took a brief look and noted a few details.
1. The supply hoses look as if they're ran true with no kinks from the supply tank under the V-berth back to the hot water heater. (No investigation has been completed downstream from the heater)
2. The water supply pump runs each time the water is cracked open and shuts off when it it is closed.
3. The shut-off valve next to supply pump opens and closes properly and has a clean stainless steel filter element. It is open.
4. The pump seems as if it "may" get noisy as it comes under load. This was determined as the noise level increases the longer it is on.
One option is to inspect the supply line from the tank back for obstructions. The pump seems as if it is struggling after 15 seconds of operation. Has anybody else come across this problem and rectified it? I suspect this architecture to be common to many mid-size and larger late model Hunters........Thanks

 

[kloudie1]

Water tank vent open and clear?

 

[Benny17441]

Noises as well as smells are hard to describe or interpret online. How old is the water pump? They do get noisier as they age. The pump is turned On and Off by a pressure switch. When you open a faucet the water pressure in the line will go gradually down until the switch activates the pump. At this point the pump will maintain a lower but steady pressure until you turn the faucet off, after which the pump will continue to operate as the pressure gradually builds up and the switch shuts it off. It is common for different pump noises to be experienced during the different cycles in pressure. 15 seconds sound reasonable as in the beginning the pump will be assisted by stored pressure on the line and then it will transition into carrying the whole load. The pump will experience its largest load just before it shuts off as it builds up to maximum pressure. There should be no reason for it to change pitch during continued pumping action other than from age and wear. It is after all a small electric motor subject to voltage fluctuations and heat. If it were me I would not concern myself with it as long as it is working adequately. A replacement can be readily found and they are fairly easy to replace so it is no big deal to wait until it fails to provide adequate service before concerning with it. Have not priced them in many years but would say that now days they could be found for $100-$150.

 

[splax]

I have noticed that my pump becomes noisy if it gets air in the pump (as in when switching tanks from the empty to full). I try to bleed the air out of the line by opening the nearest fixture. You may be drawing air in from a loose connection.

 

[John T1594]

On my 2000 H340 the domestic water pump was mounted to a fiberglass panel the made up the base of the port side settee. When the pump ran, it would vibrate the panel and act as a sounding board to amplify and "broadcast" the sound throughout the boat. On this and on my previous boats, I have unbolted the pump from the bulkhead so it would lie more horizontal and let it rest on a cushion of various density foam blocks. This reduces and dampens the pump sounds considerably. The attached water lines hold the pump in place and it has not moved in over 10 years.

 

[Terry Cox]

No brand was mentioned, but with our Flojet water pump, if the water supply becomes restricted or the tank empties, the pump tends to run at a higher pitch than normal, due to the absence of load. Our pump has four mount points each with a rubber pad to cushion vibration and noise. Periodically, the forward tank bib feed becomes clogged with a clarified material, which restricts water flow. I can always tell because the pump runs at a higher pitch due to insufficient water supply. Once I clean it out, the pump returns to normal operation.

 

[PGIJon]

We solved the problem by installing an Accumulator Tank. http://www.amazon.com/gp/product/B000N9VF6Q?psc=1&redirect=true&ref_=oh_aui_detailpage_o06_s00
-Jon

 

[sailcapt340]

Our water pump, a Jabsco 4 GPM, has been noisy since we purchased the boat new in 2000. The same echo and vibration you talk about.
I have replaced the pump twice in 15 years. Once because it just stopped about 4 years ago and just this year because the water pressure sensor stopped sensing water.
Regardless of the new pumps I still have the same noise.
I agree with John T1594, the pump has four mounting points each with a rubber pad to cushion vibration and noise.
I just finished, this year, a complete reinstalling of new waterlines throughout the boat. I went with 15mm Pex, just slightly larger hose than the original. It did seems to quiet the noise a bit.
I lie my pump on the bulkhead rather than screw it into the side of the settee also. It sits on the four rubber mounts and a thick rubber pad. The noise is much less noticeable in this position. It's a more solid base for the pump.

 

[centerline]

the problem is undoubtedly due to the vibration of the motor, which is normal in itself, and some noise will be normal and a good thing incase a waterline should begin leaking, so that you can hear the pump cycle when it should not be
if the pump is mounted to fiberglass or a thin plywood, the noise can get unreasonably loud, but it can be dampened.

if you were to remove the pump from its mounting spot and then cut a piece of 3/4 plywood as big as possible that you can fit into the space, and then mount it solidly at its corners, then remount the pump on to the plywood. it will act as a sound absorber/deadener.

if its possible you may even build the plywood with a right angle leg on it so it can be attached to two surfaces on two different planes, which will be way more solid. the larger the plywood, the better it will be... and dont scrimp and try to get away with 1/2" plywood, because if you are trying to dampen the sound, you want it as solid as possible.

and make sure the pressure line coming from the pump is not viberating against a panel somewhere, as that can cause a noise as well, especially if its laying against a thin flat fiberglass surface...