Freshwater Pump Pulsation Fixed

Dcsqatar

Well-known member
Joined
Dec 11, 2018
Messages
113
Fluid Motion Model
R-29 S
Vessel Name
Beautiful Red
MMSI Number
338348082
I received my new R29S about a month ago and have been living on it since. All is wonderful except my wife (and neighboring boats) did not like the loud pulsation noise when the freshwater pump ran. I sought Tugnut guidance and read prior posts. There was no clear consensus on a solution beyond trying to better isolate water distribution lines from the hull, which I had already done with only limited success. I went ahead and replaced the factory-installed Jabsco 3.5 gpm, constant speed pump with a Johnson Pumps 10-13329-103 Master 5.0 GPM Variable Flow Demand Pump, about $180 on Amazon. It was an easy replacement, with same size hose fittings and same 15A electrical supply requirements. It is quiet and maximum flow has improved as well. I considered an accumulator also, but in my case it was not needed. Wife and neighbors are happy. I will hold on to the old pump as a spare since some reviewers have had problems with variable speed pumps not shutting off and over heating. No such problem so far.
 
I had the same annoying issue. Cleaned out the filter that was just prior to pump inlet. Problem solved. Found some shavings from when plastic pipe cut during installation.
 
interesting!

does the extra pressure of 5GPH put any of the installed fittings more at risk of failure?
 
I'm told if you run two faucets simultaneously the thumping is reduce and even eliminated. Mind, I've not tested this. 😉
 
We had the same issue on 2019 R27-OB and I likewise replaced factory water pump with same Johnson 5.0 gpm variable flow pump. We still had some noise at the head station, which could be eliminated turning on another faucet simultaneously, which wasn't a solution. Then we installed a Johnson 2 liter accumulator and all is good. I wish we had installed the accumulator first and kept the original pump. B-O-A-T!
 
It is interesting that there is no clear consensus on this. I know two owners that put accumulators in first, only to find the problem unresolved and then added a variable speed pump too. Regarding “does the extra pressure of 5GPH put any of the installed fittings more at risk of failure” I think both pumps have the same rated discharge pressure but the new pump has a larger displacement (capacity per stroke) and therefore produces more flow. There is a marked increase in faucet flow rate, which is a bit of a concern since if crew is not careful water will be consumed faster.
 
I will repeat my comment above. I cleaned the inlet filter and problem solved. First mate was very pleased with the noise and pulsating elimination. It may not be everyone's problem but I suggest trying it before you buy a new pump or accumulator. For those that bought a new pump and it solved the issue there is the possibility that by installing a new pump you unknowingly took care of the dirty filter problem. This is especially true of new boats. What I found were plastic pipe shavings that were probably created during the manufacture of the boat.

The reason even a small amount of debris can cause the issue is because these pumps work based on measuring pressure on inlet and outlet side. when it is unequal pump either turns off or on to compensate.

It is a free possible solution worth the 15 minutes to take apart, clean and put back together. the connections are clips that are easy to remove. Good idea to check any other filters at the faucets or shower head.

I am going to try wrapping any exposed water lines in pipe insulation to eliminate thumping which is unrealted to pump pulsation.
 
If you plan on cleaning the pump filter as a regular maintenance procedure which it should be. Installing a shut off valve between the water tank and pump makes the job easier. I guess this depends on the location of the pump and tank. In my case the pump is located in the 1/4 berth next to the tank. If there is any water in the tank and the filter is removed off the pump the water from the tank drains and makes a mess. With the shut off valve installed there is minimal water drainage a small towel is sufficient for water absorption of lost water.
 
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