problems with pressurised water system

Another unsuccessful day, after remaking all connections the only improvement was that it now primes better with a little help, but still cycles on/off every 20 secs or so.
Anyway I have ordered a new Jabsco Par Max 1.9 12V automatic boat water pump Model 31295-0292 for under 60 quid.
Try that when it arrives.
Thanks to all for your inputs.

You will also be fitting an inlet strainer I hope . eg http://www.jabscoshop.com/marine/pu...ump-inlet-strainer-hose-for-par-max-pumps.htm
 
I suspect the original fault may be in the pump body itself. I had one which had a tiny hairline crack which sucked air in when pumping but was too microscopic to leak water out when not pumping. It therefore constantly cycled trying to compress the newly sucked in air in the pipework.
Your new pump should cure the problem. Make sure you do not overtighten the pipe connectors in the pump body. You can use some ptfe tape with a solution like 'perfect seal' to effect a totally water and airtight connection.
 
Yes VicS, I have flushed out and refitted the original filter in the input line for now.
Onto the next problem, Jabsco manual toilet back-filling into bowl. Torn between replacing joker valve etc or fitting twist and lock pump.
 
Ferring, the filter to which Vic refers is to remove grit and particles from your tank and prevent it going through your pump. You are referring to the original water filter which is designed to remove bacteria and other animals from your water supply. They do completely different things. The bacteria filter should be totally removed or replaced. It will do you tummy no good if it is old. It should only be fitted after the pump. By fitting it before the pump you are restricting the pumps ability to draw the water from the tank. Effectively you are creating a restriction between the tank and the pump which you do not need.
 
Onto the next problem, Jabsco manual toilet back-filling into bowl. Torn between replacing joker valve etc or fitting twist and lock pump.

Just the water in the immediate section of discharge pipework flowing back? If so the " base valve gasket" and the Joker valve need replacing.
If back flow continues and overflows the bowl then you either do not have a vented antisyphon loop in the discharge pipe or the antisyphon valve itself is not opening and requires attention/cleaning.

A Twist and lock pump is usually a good idea. (IIRC anew base valve gasket comes with it and joker valve?)
 
VicS yes it is a very slow back-fill and does not overflow (unless bouncing or heeling heavily). Shutting the waste sea cock seems to stop it, so I presume that creates a vacuum. There doesn't seem to be a vent only a high loop of waste pipe.
 
VicS yes it is a very slow back-fill and does not overflow (unless bouncing or heeling heavily). Shutting the waste sea cock seems to stop it, so I presume that creates a vacuum. There doesn't seem to be a vent only a high loop of waste pipe.

make sure the vent valve in the top of the loop is operating. It should open to break the syphon effect although the base valve should stop the back flow if in good order esp if a twit and lock pump is fitted . That has a modified piston that clamps the valve shut when locked.
Joker valves are aptly named IMO

You should also have a vented loop in the inlet pipe between the pump and the bowl ( not between the seacock and the pump). The little wet/ dry switch is not really intended to stop water syphoning in via the inlet, merely to stop the pump pumping water in. It only has a couple of weighted rubber flaps in it!
 
I'm not clear whether you have a hot water tank/calorifier as well. I've been having similar problems (and have posted recently about my recurrent pump "grrumping") The cause turned out to be a second pressure relief valve on the hot water tank which was releasing water back into the cold feed. I'm not sure why there were two pressure relief valves (my post yesterday asking about this has had no responses :-( Hope this helps!
 
Thanks all for the inputs, fitted new pump & strainer today and problem seems resolved. Pump primed immediately and once air bled out of system pump shuts off as soon as taps closed. I monitored for about 20 minutes without the pump kicking in.
Now onto the toilet issue, waste draining back into bowl. I suppose a new twist and lock pump is on the cards to replace the obsolete system.
 
Thanks all for the inputs, fitted new pump & strainer today and problem seems resolved. Pump primed immediately and once air bled out of system pump shuts off as soon as taps closed. I monitored for about 20 minutes without the pump kicking in.
Now onto the toilet issue, waste draining back into bowl. I suppose a new twist and lock pump is on the cards to replace the obsolete system.

It does seem a sensible upgrade and IIRC comes with the new parts ( bottom valve gasket and joker valve) you might replace anyway. Then consider fettling up the old pump to keep as an emergency spare.

It may be worth overhauling the old water pump to keep as a spare as well.
 
Just a thought but I got a brand new Jabsco toilet with large bowl, seat, lid and the Twist and Lock version of the pump for around £100 on eBay. I then sold the old assembly complete on eBay for £40 - collection only.

When you look at the cost of just buying the Twist and Lock conversion it made sense to replace the whole lot.

Richard
 
Just to close out this post:
New Twist and lock toilet arrived and fitted today. Only snag was the new toilet has a different footprint for the mounting studs. Some drilling and epoxying and all is well.
Can't believe the difference, no more two handed wrestling to get the pump started and so far so good, no back-fill into toilet bowl.
Well worth the 100 quid spent.
Thanks to all for your inputs.
 
Hello Ferring, i want to buy a Mirage 2700, but the owner has no other papers than a sales contract wuth the old owner, but in my counry i need at least a paper issiued by the manufacturer with technical data and specifications... please do a paper like this exist for the boat? i
thanks for any help...
 
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