Fresh Water system has low pressure at faucets

GregR

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Bought the boat this time last year. During survey there was low pressure at the faucets, like a dribble, and the fresh water pump would not shut off. Fresh Water pump was replaced as part of the sale. This helped but the pressure was still weak and the pump ran for a long time anytime I turned a faucet on. Boat then went into storage for the winter.

This spring I found a leak in one of the fresh water lines in the engine compartment and repaired it. Slight improvement. Pump would still run for a while anytime I turned on a faucet though. I noticed water on the swim platform when the pump was on, did some looking, discovered the source was the dock water regulator/filler, so I replaced that. After replacing this the pump would run for a only few seconds when turning on a faucet (this was good), then stop, so it felt like the problem was resolved. I get an initial good surge of water, then a dribble again though.

Everything works great when connected to dock water.

It's an issue now because I need to winterize the fresh water system and I don't have enough water flow to do so.
 
Check the inlet side for blockage. There is usually a screen filter that gets plugged.
 
Thanks, yup I pulled the screen and cleaned it out, same result.
 
flush some water back into the tank from the pump inlet side.
 
You are suggesting disconnect the hose from the tank to the pump, at the pump, and then push some water thru from the pump to the tank? Makes sense, if there's a clog there. Could I use an air compressor as well?
 
Yes, an air compressor at low pressure should work as well.
 
It could be a spider nest in the vent as well. If it can't suck air it can't push water. to test remove the filler cap if it works better replace the cap and blow out the vent line.
 
I would bet on the clogged vent but is there a cartridge water filter? If so it could be clogged.
Jim
 
I doubt it s a clogged vent as you notice it when filling the tank

If flexible hoses there could be a pinched hose, or someone could have replaced a hose with cheap stuff that collapses.

Inlet screen, pre filter before the pump, leak on the suction side.

Or it could be the pump. Are you sure it was replaced? New stands for Never Ever Worked anyway :).

Finally, check the voltage at the terminals with the pump running
 
I'm pretty sure it's not the vent, assuming this is the same as the overflow. When I fill it up good water flow comes out of the hull overflow.

The pump is new, I confirmed that.

I'll be back on the boat next weekend and will check all these. I plan to take my air compressor with me.
 
What kind of pump? If a diaphragm pump check a piece of dirt preventing one of the valves from closing
 
I'm not sure what brand/model. It's red and white if that helps. I'll be back on boat Friday.
 
Did you check your aerators on your faucets? Just unscrew one and see what kind of flow you get. Mine build up some scale over time but if you are getting surge first then a drop in pressure, you have a different issue. It's easy to check though.
 
quote:

Originally posted by MichaelNJ

Did you check your aerators on your faucets? Just unscrew one and see what kind of flow you get. Mine build up some scale over time but if you are getting surge first then a drop in pressure, you have a different issue. It's easy to check though.






I did, cleaned all 4 of them, same problem.
 
I used my air compressor with 30 lbs of pressure, disconnected the hose at the water pump between the pump and the freshwater tank, blew air until I could hear bubbling in the tank, that fixed it
 
Pickup tube must have been blocked with something. Maybe a piece of sealant. It may find it's way back there again if it didn't break up or dissolve.
 
Probably cleared either pickup tube or vent. Easy / cheap fix. Nice.
Jim
 
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