problems with pressurised water system

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Ferring

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My recently acquired Mirage 2700 has a pressurised cold water system. The pump cycles about every minute even when no water is used. Water pressure is good at both taps when used.
I see from a web article (http://www.jabscoshop.com/advice-and-support/jabscoshop-about-pressurised-fresh-water-pumps.htm), that the accumulator should be Teed into the main pump output, but on my system the accumulator tank is in line, i.e. the water flows through the tank to the taps. It is a Jabsco pump. There are no apparent water leaks.
Can anyone suggest where I should start? Does the accumulator tank configuration need to be changed? Also there is a teed in manual pump tap to the pump input at the tank outlet. As I see it this shouldn't cause the problem as it is non pressurised side of pump.

Thanks
 
Your accumulator sounds weird, usually a single in/out at one end and an air fill (to set pressure) at the other...

If there are absolutely no leaks then the only place the water can go is back the wrong way through the pump, new valve might be in order. Similar problem mentioned here recently, the solution was a 1 way valve up stream of the pump inlet.
 
Ferring said:
My recently acquired Mirage 2700 has a pressurised cold water system. The pump cycles about every minute even when no water is used. Water pressure is good at both taps when used.
I see from a web article (http://www.jabscoshop.com/advice-and-support/jabscoshop-about-pressurised-fresh-water-pumps.htm), that the accumulator should be Teed into the main pump output, but on my system the accumulator tank is in line, i.e. the water flows through the tank to the taps. It is a Jabsco pump. There are no apparent water leaks.
Can anyone suggest where I should start? Does the accumulator tank configuration need to be changed? Also there is a teed in manual pump tap to the pump input at the tank outlet. As I see it this shouldn't cause the problem as it is non pressurised side of pump.

Thanks
Click to expand...
IF there really are no leaks
Most probably the little valves in the pump are not sealing properly and the pressure is leaking back though the pump

May just need a clean otherwise a pump valve overhaul called for.

If no filter on the pump suction fit one
 
You may still have a leak. Have you looked at the safety valve on the calorifier?

My pump failed at the pressure switch & gave the same symptoms. I traced it to a faulty pressure switch
I bought a new pump & that solved the issue.
I then bypassed the pressure switch & mounted the pump in the bilge with a switch in the cabin. I connected the outlet to the shower hose outlet & put a nine foot length of hose on the inlet which I can move about the boat. Now if I get any small water leaks or leaks below the engine that the main pump does not move I can hoover the water up with the old water pump. Being a half inch hose it nearly gets the lot so the old unit was not completely wasted
 
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Thanks all for the suggestions.
I have looked more into the setups on internet and it seems the small in line tank (probably about 1 litre) is not an accumulator as there are only in and out water connections. Not sure what it is and maybe I will bypass it tomorrow after trying to clean the pump valves, any advice on how to strip the pump?
No hot water system installed.
 
Our experience was similar. The acumulator is the star culprit! Assuming the system is 'mature' then this is where the slow loss of pressure and hence the hunting of the pump happens. Replace it and everything should be OK.

Whilst you are doing all this, put a stop tap in the main line from the tank to the pump. Enables you to work on the system without having to drain it all down.
 
Apologies if this is useless info but could there be a sensitivity adjustment on the pressure switch as there is in caravan systems?

It involves turning a small screw until the pump operates, then turning it the opposite way a set number of turns.
 
Ferring said:
Thanks all for the suggestions.
I have looked more into the setups on internet and it seems the small in line tank (probably about 1 litre) is not an accumulator as there are only in and out water connections. Not sure what it is
Click to expand...

Perhaps it is some form of activated carbon, or similar. water freshness filter. If it is it would probably have to be replaced every year. It about the right size.

If it is not leaking it is not connected to your pump cycling problem
 
I think that you will find that It is a pressure tank that is filled with air in the top part. This compresses & as the tap is turned on the air reduces pressure & pushes the water out so that the pump does not have to work immediately or keep cycling. It works like an expansion tank on a boiler ( not the one in the loft the one in the boiler if you have one) & can absorb pressure change. It is probably leaking air & that is why you cannot see water. Take it off & see if you actually need it ,or drain it out & re connect. try that before playing with the pump. I doubt that the pump valves have any obstruction in them
 
Daydream believer said:
I think that you will find that It is a pressure tank that is filled with air in the top part. This compresses & as the tap is turned on the air reduces pressure & pushes the water out so that the pump does not have to work immediately or keep cycling. It works like an expansion tank on a boiler ( not the one in the loft the one in the boiler if you have one) & can absorb pressure change. It is probably leaking air & that is why you cannot see water. Take it off & see if you actually need it ,or drain it out & re connect. try that before playing with the pump. I doubt that the pump valves have any obstruction in them
Click to expand...

I though the Op had established that it is not an accumulator but if you are right, and the pump cycling is due to air leaking from the tank, once all the air has leaked the cycling will stop.
 
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''If there really are no leaks
Most probably the little valves in the pump are not sealing properly and the pressure is leaking back though the pump
May just need a clean otherwise a pump valve overhaul called for.
If no filter on the pump suction fit one''

+1
Jock89
 
On a typical Westerly installation, the manual pump pumps into the pressurised side of the system, and has its own connection to the tank for its supply. This annoying problem was caused by the pressure leaking back through the foot pump. I proved this by taking the connection to the pressure system off and blocking it with a AA battery which is a perfect fit. The problem stopped at once.

I purchased a new one - not cheap, and it did the same thing! Asking Whale about it, they said they were not surprised, and suggested fitting a one way valve on the tank side of the manual pump. So much for selling things that work. And yes - the one way valve worked! But then I had wasted all that money and they would not refund as it was now 6 months old.
 
Thanks again all for the suggestions.
Spent a few hours trying some things today, without any success.
The mysterious small tank turns out to be a filter fitted on the pump output, not input, which I removed..
I also removed the Teed in manual pump from the input.
I stripped the pump and removed minimal amount of dirt from the diaphragm and valves.
I also tried blocking off the pump output but this caused the pump to run continuously, whereas it cycles when connected to taps normally.
I also tried connecting the output directly to a single nearby tap but still cycling, which is how I left it.
The pump needed assistance to prime by pouring water back down the system every time I broke the lines, the water tank is at a low level below the pump. Still no signs of any water leaks.
Tomorrow I will try resealing the connections in the single tap configuration.
Any other help much appreciated.
 
Ferring said:
Thanks again all for the suggestions.
Spent a few hours trying some things today, without any success.
The mysterious small tank turns out to be a filter fitted on the pump output, not input, which I removed.. A water purifier of some sort I would guess
I also removed the Teed in manual pump from the input. Good that eliminates that
I stripped the pump and removed minimal amount of dirt from the diaphragm and valves.
I also tried blocking off the pump output but this caused the pump to run continuously, whereas it cycles when connected to taps normally. It ought to cut out but perhpas having the outlet blocked means if would not have purged itself of air
I also tried connecting the output directly to a single nearby tap but still cycling, which is how I left it. zero progess then :(
The pump needed assistance to prime by pouring water back down the system every time I broke the lines, the water tank is at a low level below the pump. Still no signs of any water leaks. A diaphragm pump with good clean properly seating valves ought to self prime
Tomorrow I will try resealing the connections in the single tap configuration.
Any other help much appreciated.
Click to expand...


I reckon a full pump overhaul with appropriate overhaul kits may be called for. Some people would splash the cash and fit a complete new pump,
 
VicS said:
... Some people would splash the cash and fit a complete new pump,
Click to expand...

A while ago the Surflo on Gladys was leaking, and being a complete PITA. I bought a brand new Jabsco for less than £60 when the Surflo repair kit was c £30 and saved myself at least another £30 in my time. It took about 10 min to fit a new pump, job's a good 'un
 
As said it could be the presusure switch has failed or the pressure tank, check the pressure. Another thing I would do is take the pump apart and check the diaphragms at the bottom of the pump if the water out one is split that is the problem. The main problem we had with our Jabsco water pump when long distance sailing is I can't remember how many times I had to change the pressure switch.
 
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.
 
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