Jabsco Par Max 4 fresh water system flow problem

[Seven Spades]

I would buy another water pump, we always carry a spare. If your water pump fails it is miserable, I you buy a spare you can fit it and see if the problem goes away, if it does all is good and if not then you have a spare pump.

 

[billskip]

Or the pressure switch controlling the pump is faulty and not operating at the correct pressures. We need a pressure gauge fitted into the system so that we can see exactly what is going on with the pump cut in pressure! The fault finding needs to be logical and scientific, otherwise it’s just guesswork!

A pressure gauge does help and if easy to fit ok, but it is not the cause of the problem, of course it's guesswork trying to fix on a forum ...
I have worked with many many (I won't say hundreds but not far short) of these systems, installation and repair from systems with accumulators 3mtrs high x 1½ mtrs diameter and smaller than Skylark's system...the all work the same way.
It is not good for the pump to "hunt" as this will cause excessive heat in the switch contacts and pump.
Unfortunately Skylark is 250 miles away from his boat and it's difficult for him to give information.
The differential pressure switch works on a high pressure " off" diaphragm and the low pressure "on" is set by increasing or decreasing the "gap" .

If Skylark increases the "low pressure on" he will just close the gap and the pump will "hunt" more quickly..it will give him better water pressure and also a future problem. It will not fix the problem.

 

[JOHNPEET]

A pressure gauge does help and if easy to fit ok, but it is not the cause of the problem, of course it's guesswork trying to fix on a forum ...
I have worked with many many (I won't say hundreds but not far short) of these systems, installation and repair from systems with accumulators 3mtrs high x 1½ mtrs diameter and smaller than Skylark's system...the all work the same way.
It is not good for the pump to "hunt" as this will cause excessive heat in the switch contacts and pump.
Unfortunately Skylark is 250 miles away from his boat and it's difficult for him to give information.
The differential pressure switch works on a high pressure " off" diaphragm and the low pressure "on" is set by increasing or decreasing the "gap" .

If Skylark increases the "low pressure on" he will just close the gap and the pump will "hunt" more quickly..it will give him better water pressure and also a future problem. It will not fix the problem.

With all due respect, I’m fully aware of how these systems are meant to work and I really don’t want to get into a discussion about which of us has the greater knowledge in this respect. Prior to retirement, I had a career spanning over 40 years in Engineering Building Services in the NHS, including a period as Chief Engineer for the largest Healthboard in Wales. I was also professionally registered with the Engineering Council. I’ll leave that there!

Some of the comments that you’ve made within this thread haven’t actually made any sense, so I chose not to respond to those.

Fitting the gauge is to be considered a diagnostic tool, to help identify the cause of the fault - not a remedy!

Fault diagnosis has to follow a logical path - understand how the system is supposed to function, understand the symptoms of the fault (note my initial response in this thread), determine/measure the points of failure, determine the cause of the fault.

Without the pressure gauge, which would not be expensive to fit permanently into the system and would be a valuable tool for the future , we are missing the vital facts for stage 4 of the above.

This is almost certainly a pressure switch or pump fault (or associated problem such as a loose connection) but I prefer to work on facts, not guesswork!

 

[billskip]

With all due respect, I’m fully aware of how these systems are meant to work and I really don’t want to get into a discussion about which of us has the greater knowledge in this respect. Prior to retirement, I had a career spanning over 40 years in Engineering Building Services in the NHS, including a period as Chief Engineer for the largest Healthboard in Wales. I was also professionally registered with the Engineering Council. I’ll leave that there!

Some of the comments that you’ve made within this thread haven’t actually made any sense, so I chose not to respond to those.

Fitting the gauge is to be considered a diagnostic tool, to help identify the cause of the fault - not a remedy!

Fault diagnosis has to follow a logical path - understand how the system is supposed to function, understand the symptoms of the fault (note my initial response in this thread), determine/measure the points of failure, determine the cause of the fault.

Without the pressure gauge, which would not be expensive to fit permanently into the system and would be a valuable tool for the future , we are missing the vital facts for stage 4 of the above.

This is almost certainly a pressure switch or pump fault (or associated problem such as a loose connection) but I prefer to work on facts, not guesswork!

Ha ha ha I won't bore you with my history, I was only trying to give confidence to the op that I am familiar with the system and it's problems.

As for the NHS...well I also have a lot of experience with them normally it was due to the resident engineer not being able to trouble shoot the problem...you carry on willy waving, I have not in this thread said the help you are trying to give is unhelpful.

 

[Skylark]

Thanks to all for your comments and observations.

Having a root around, I’ve found this 1bar FSD gauge which I recall using to pressurise my Yanmar sail drive when I suspected a leak. Looks like 2bar versions are widely available for little money.



The blue plastic pipe is about 8mm dia and has quick-fit fittings.

A few years ago I had to replace galley tap and, iirc, it has plastic quick-fit (very different size to the above) pushed and Jubilee clipped into the red and blue rubber water hoses.

So, what’s the correct name for the blue plastic hose in the picture and is there a fitting with taper to push into a rubber hose?

Is there a difference in water pressure between hot and cold outlets?

The easiest access will be the galley. If I can adapt the gauge above (2 bar version) to fit with tapered plug and jubilee clip into either hot or cold rubber pipe, I’ll be able to measure pressure as an open tap flows.

Does this sound like a plan?

 

[billskip]

Does this sound like a plan?

Sounds like a good plan.
Let us know the results please

 

[JOHNPEET]

Thanks to all for your comments and observations.

Having a root around, I’ve found this 1bar FSD gauge which I recall using to pressurise my Yanmar sail drive when I suspected a leak. Looks like 2bar versions are widely available for little money.

View attachment 184112

The blue plastic pipe is about 8mm dia and has quick-fit fittings.

A few years ago I had to replace galley tap and, iirc, it has plastic quick-fit (very different size to the above) pushed and Jubilee clipped into the red and blue rubber water hoses.

So, what’s the correct name for the blue plastic hose in the picture and is there a fitting with taper to push into a rubber hose?

Is there a difference in water pressure between hot and cold outlets?

The easiest access will be the galley. If I can adapt the gauge above (2 bar version) to fit with tapered plug and jubilee clip into either hot or cold rubber pipe, I’ll be able to measure pressure as an open tap flows.

Does this sound like a plan?

Yes, that sounds like a plan.
You’ll likely need two fittings to adapt what you have to a 12mm or 15mm hose connector depending on what size the flexible pipe is to your taps. If the blue pipe is definitely 8mm OD, you can get a 8mm push on connector to 1/2”bsp female . Then get a hose connector to suit your flexible pipe with 1/2”bsp male thread which will screw into the above fitting. I can send you some photos later if needed.

 

[JOHNPEET]

Is that a screwed plug at the other end of the manifold that you have?

 

[Skylark]

Is that a screwed plug at the other end of the manifold that you have?

Both ends are threaded but I confess that I had one of my Assy Engineers make it up for me. The large hex piece is a valve, handle is hidden from view, for venting.

Happy to measure anything.

Picture and description of what’s required to connect 8mm plastic pipe to Beneteau red/blue rubber water hose very much appreciated.

I’ll gather all of the required hardware before booking train to Scotland. Boat now on hard for winter. I tend to visit once per month over winter time.

 

[Boater Sam]

I was not suggesting that the accumulator was the problem, it cannot be, but just suggesting the easiest way to get the correct pressure into it, once you have sorted the pump.
The pump or pipework is the problem. Those pump pressures are very low, uncommonly so IME.

Do all the taps have aerators on the outlet? They can block with grit. Same with shower roses.

 

[Dogone]

I’ve got two water pumps. All things fail on a boat and if it’s something, like this is, that stops the show when it fails then you need two (as suggested above). I happen to have the Marco pumps, which I recommend highly. No accumulator is needed. They are variable speed, constant pressure devices, self contained, very compact and not terribly expensive. Fit one in parallel with a 3 way valve and a changeover switch whilst you sort out the bust one at leisure.

 

[Skylark]

I’ve got two water pumps. All things fail on a boat and if it’s something, like this is, that stops the show when it fails then you need two (as suggested above). I happen to have the Marco pumps, which I recommend highly. No accumulator is needed. They are variable speed, constant pressure devices, self contained, very compact and not terribly expensive. Fit one in parallel with a 3 way valve and a changeover switch whilst you sort out the bust one at leisure.

Interesting comment, thanks.

This, for example?

Marco UP2/A Automatic Water Pressure System

 

[Dogone]

Interesting comment, thanks.

This, for example?

Marco UP2/A Automatic Water Pressure System

Your link is to the pressure switched pump. The E version is what I have with electronic control. I have the dual 6 with a 12 as backup. You can pick one with the pressure and flow rate to suit your boat. Here’s the range:

Electronic Pressure System Pumps | Marco Pumps Shop

 

[Skylark]

To close this thread and to thank all who offered their advice.

I was offered a warranty (2nd) replacement for the (1st) replacement pressure valve and the issue has now gone away. The first replacement Jabsco valve was evidently not to spec.