How to fix freshwater system problem

[skipjack27]

I have a 27' flybridge cruiser with a freshwater tank and pump that reticulates to 8 hot and cold water taps (sink, washbasin, and 2 showers) on board. It has quite suddenly refused to turn off after being turned on and pumping up to pressure. It happily supplies water to all outlets, but will not turn off automatically after the outlets are shut off, and has to be turned off at the fuse panel.

I am assuming that this indicates an air leak somewhere in the pump or water system - a leak that prevents the pump from sensing the restoration of normal pressure and shutting off automatically. Is this correct?

On that assumption, I've carefully tightened the connections to the water tank and to the in-line water filter near the tank, but to no effect. I am guessing that air is being sucked in by the pump:

1. either at the pump itself (leaky seals? Can this be a problem? It is an old pump - may not have been replaced for more than 20 years)

2. or at the connections to any one (or more) of the 8 tap connections.

Am I on the right track? Where is the problem most likely located, in the view of those with experience with this problem?

Jeff

 

[Grandad]

Re: How to fix freshwater system problem

I suspect that your pump is no longer able to attain the pressure setting on your pressure switch. If there's a pressure gauge installed and you know the historic system pressure level, you could see if the pressure is up to normal levels. If unknown, you could try adjusting your pressure switch to a lower setting to see if the pump can maintain a lower pressure. I suspect your pump parts have worn to the extent that it needs rebuilding. - Grandad

 

[Mischief Managed]

Re: How to fix freshwater system problem

I agree with Grandad, it's likely not making enough pressure and I would only suspect a leak if the tank was going dry and the cabin was getting wet. Definitely look into a rebuild kit, pumps are usually very easy to rebuild.

If the motor needs new brushes and/or bearings, don't be afraid to change them either. I "rebuild" electric motors all the time (I just ordered a $2.28 6200 RS bearing for a palm sander motor last night as a matter of fact...) and there's nothing complicated about them.
Bearings and brushes come in standard sizes, so it takes little effort to find them for sale on the internet. You don't need to know the motor manufacturer.

 

[Grub54891]

Re: How to fix freshwater system problem

Cap the outlet hose at the pump itself. Turn it on and see if the pump builds enough pressure. If it does you have a leak.If not the pump is wore out. Had one that had no external leaks but the pump would still run till capped off. After a bit of deep thoughts,I found the heat exchanger in the water heater had gotten a hole in it from age. The freshwater was going out the engine exhaust hoses so no inside leaks would show up.replaced water heater and problem solved!
Grub

 

[Merc4ever]

Re: How to fix freshwater system problem

After 20 years I would say it served it's life and needs to retire. I would put in a new pump but that's just me.

 

[Grub54891]

Re: How to fix freshwater system problem

After 20 years I would say it served it's life and needs to retire. I would put in a new pump but that's just me.

Yeah the pump is old,I was just stating that the pump might be ok,just check for a water heater internall leak.I changed the pump in the afore mentioned thread and sill had the same problem. Just passing on my experience.
Grub

 

[skipjack27]

Re: How to fix freshwater system problem

Thanks for those comments, guys. I think the time has come to replace the pump...