Another Fresh Water Pump question,

P

Paul&Ness

Well-Known Member
Joined
27 Apr 2014
Messages
175
Location
Southampton
Visit site
I am still finding my way round the various systems on my new, to me, boat (Princess 368) and I have a question about my FWP... When I turn on the fresh water pump at the elec panel the pump runs continuously whether the tap is on or not! Is that normal and if so is there such a thing as a FWP with a pressure activated on off switch?
 
Sounds like either a significant leak in the system, a fault with the FWP (which generally have a built in pressure swtich), or for some other reason it's not building pressure to switch off the pump.

I would have thought it unlikely that a boat like a Pincess would be delivered with a freh water pump that is not self regulating.

Does the pump sound like it's building pressure, or is it just running freely? Do you have water coming out of the taps at a normal rate?

Cheers,
Paul
 
The pump doesn't seem to build any pressure and it seems like it's just running... There is water coming out of the taps but at a very low pressure! The pump looks like an original, fitted around 1992. There is no accumulator as far as I can see, just a calorifier! I have filled the water tanks so that there would be as much pressure as possible but no change. The tanks are now 1/3 full as I have been draining the system to get the pump out.
 
sounds like the impellor in the pump has gone if no big leaks - not serious you can buy them easily enough. Or if its one of the newer style pumps they can usually be rebuilt too. Have a look at the pump and find the model number then go to ASAP supplies on the web and they will probably have what you need. Re pressure switch. usually there is a pressure switch - earlier boats it was seperate and easy to adjust and fix. Later model pumps have the pressure switch built in. Its usually just a micro switch in either case. But again you need to take ita aprt to find out which switch you have. Maplins sell micro switches.
 
I have stripped the pump down and it works on a diaphragm system. I cleaned and inspected the diaphragm as best I could and there was no visible damage. I appreciate that it could be a minuscule hole or tear and I may have missed it. I think I leaning towards changing the pump... 23 years sounds like a good innings!
 
There's not much to the diaphragm pump - a diagphram and a couple of valves - you can buy overhaul kits, but if you can't see anything wrong I doubt as there is anything wrong. Have you tried getting to pump out a bucket of water to see if it pumps okay?

If it's pumping okay in a test with a bucket of water and a hose pipe, but just spinning on the boat, my guess would be it's not the pump - perhaps air in the system, or a leak elsewhere? I get the same behaviour if I let the tank run empty - it takes time to purge the air - try opening all the taps to purge the air if that's the case.

Cheers,
Paul
 
had a minute, really impossible to see (er, almost!) hole in one of the two valves in a fresh water diaphragm pump. A repair kit and it's like new (must be the original fitting so reaching 40y...)
Could also be some dirt in the faces of the valves not letting them built the pressure.

cheers

V.
 
I took the pump apart, quite easy, cleaned and inspected it but couldn't see anything... I've been working on the problem for a couple of days, on and off, so I think a new pump may be worth the investment.
 
You must log in or register to reply here.

Share this page

Top