Water Pressure

[Traveller]

Fitted new Jabsco pump to the water system. Would not switch off. No identifiable leaks but the pump just kept working, although I did not think the flow coming out of the taps was anything to shout about. Supplier replaced on basis it might be a dud but the same thing is happening with the new one. Been right through the boat - no leaks and the bilge is dry. It is a Jabsco Par Max 2.9 and is driving two sinks and Paloma - so two hot and two cold taps plus shower. At testing I was only running one tap at at time and made sure there was no air in the system. I just cannot fathom this out - maybe the accumulator is dodgy but would that cause this?

Help!!

[WotEver]

If it doesn’t switch off there can only be three causes...

 

1. It’s not pumping very well and cannot raise the pressure. 

2. The pressure switch is faulty or set too high. 

3. There is a leak (a big one). 

 

As 1 & 2 are unlikely to be a pump fault on two different pumps and as you’ve discounted 3, then I’d firstly ensure that you have no blockage prior to the pump (like a blocked filter). If that all seems fine then try reducing the pressure. 

 

 

[bizzard]

9 minutes ago, Traveller said:

Fitted new Jabsco pump to the water system. Would not switch off. No identifiable leaks but the pump just kept working, although I did not think the flow coming out of the taps was anything to shout about. Supplier replaced on basis it might be a dud but the same thing is happening with the new one. Been right through the boat - no leaks and the bilge is dry. It is a Jabsco Par Max 2.9 and is driving two sinks and Paloma - so two hot and two cold taps plus shower. At testing I was only running one tap at at time and made sure there was no air in the system. I just cannot fathom this out - maybe the accumulator is dodgy but would that cause this?

Help!!

Sounds like a restriction in the main pipeline from the tank, or muck in he tank, or tank vacuuming, release the filler cap and try it. You could take the inlet pipe off the pump and blow down it back to the tank which might shift any restriction. Have you plenty of water in the tank.   Could also be an enlarged prostate problem.

[Traveller]

Thats useful chaps thanks. I had though about a partial blockage but discounted that on the basis that as water was flowing from the taps and shower the pressure would still build up eventually. Apparently there is  no way to adjust the pressure switch on a Jabsco!

[Boredrider]

Is the pump overcoming the pressure relief valve on the calorifier?

[Machpoint005]

34 minutes ago, WotEver said:

If it doesn’t switch off there can only be three causes...

 

1. It’s not pumping very well and cannot raise the pressure. 

2. The pressure switch is faulty or set too high. 

3. There is a leak (a big one). 

 

As 1 & 2 are unlikely to be a pump fault on two different pumps and as you’ve discounted 3, then I’d firstly ensure that you have no blockage prior to the pump (like a blocked filter). If that all seems fine then try reducing the pressure. 

 

 

 

4. Knackered accumulator?

[bizzard]

As long as its not leaking a knackered accumultor won't cause it, in fact it might improve matters.

[Machpoint005]

1 minute ago, bizzard said:

As long as its not leaking a knackered accumulator won't cause it, in fact it might improve matters.

It wouldn't make the pump to cut out (stop) as it should, although I agree it might improve the flowrate.

[Chewbacka]

When I had a dead cell on a battery the voltage was low enough for the pump to run but it went slow  and even after a 30secs with all taps off it could not achieve enough pressure to switch off.  Taps on and flow was not too bad.  So check voltage at the pump.

[DHutch]

20 minutes ago, Boredrider said:

Is the pump overcoming the pressure relief valve on the calorifier?

That was my first thought.

 

Whats the flowrate and or pressure like on the taps. If you open them slowly, what do you get?

Is the water level in the tank going down? (might b hard to see if tank is large, not indicator)

Can you dis-connect the outlet and see if the pump is running/pumping as expected? Put a tap on that and test?

 

 

Daniel

[bizzard]

I have a feeling in me water that Traveller might not have a calorifier. He mentions a Paloma. He may even have an air cooled engine with no waterworks.  But of course he may have some other kind of hot water boiler feeding a calorifier.

Edited November 28, 2018 by bizzard

[Traveller]

BMC 1.5 but you are correct bizzard in that water heating is via a Paloma. When I crack the taps water comes out ok, although as I said earlier it seems a little lack lustre re the flow rate and especially so on the Paloma side of things. The Paloma heats the water ok though so there is enough flow-through it to fire to up. The pump is pumping water as expected.

Edited November 28, 2018 by Traveller

[ditchcrawler]

1 hour ago, Chewbacka said:

When I had a dead cell on a battery the voltage was low enough for the pump to run but it went slow  and even after a 30secs with all taps off it could not achieve enough pressure to switch off.  Taps on and flow was not too bad.  So check voltage at the pump.

Reading the rest of this thread you could be right, maybe not a duff battery but low voltage at the pump for some reason. Check the voltage at the pump with the pump running.

 

Second thought before you do that, try the pump with the engine running, that's an easier first check as the charging voltage may make it work OK and narrow things down a bit

 

[Traveller]

The previous pump worked ok until it broke! Voltage is a thought though, although I have tried it with the generator charging the batteries as well as with engine running. What reading would you expect?

[Tony Brooks]

18 minutes ago, Traveller said:

The previous pump worked ok until it broke! Voltage is a thought though, although I have tried it with the generator charging the batteries as well as with engine running. What reading would you expect?

With the pump running the charging voltage minus any voltdrop along the cables. It should be no less that whatever the battery voltage is minus about 0.5 volt.

[ditchcrawler]

above 12 volts on the pump motor with the pump running

[philjw]

Just a stupid thought, they haven't given you a 24V version of the pump have they?  I don't know if that would work at all on a 12V system but it definately would not perform well ?

[Traveller]

Thanks all. As helpful as ever ?

[Machpoint005]

15 minutes ago, philjw said:

Just a stupid thought, they haven't given you a 24V version of the pump have they? 

Not a stupid thought at all. Forgetting about the bleedin' obvious is stupid, not asking the question is stupid, and as it used to say on drawings

"IF IN DOUBT ASK"!

[WotEver]

22 minutes ago, philjw said:

Just a stupid thought, they haven't given you a 24V version of the pump have they?  I don't know if that would work at all on a 12V system but it definately would not perform well ?

That’s actually a bloody good thought

4 hours ago, Machpoint005 said:

4. Knackered accumulator?

Not unless it’s leaking and OP said ‘no

leaks’  

[Flyboy]

2 hours ago, philjw said:

Just a stupid thought, they haven't given you a 24V version of the pump have they?  I don't know if that would work at all on a 12V system but it definately would not perform well ?

I think you may be on the money there. Definitely not a stupid thought.  A quick check on the current draw will give an indication of whether it's possibly a 24volt pump. Running on 12 volts would give approx half the draw of a 12volt one.

[Traveller]

Spot on. They have sent me a 24v model in error. I never even thought to look, assuming as I did that 24v would not even run.

 

I could have been looking for a leak forever without the great help from this forum ?

[rusty69]

Good call Philjw. I would never had thought of that. 

Edited November 29, 2018 by rusty69

[MtB]

57 minutes ago, rusty69 said:

Good call Philjw. I would never had thought of that. 

 

Curiously it crossed my mind as I started reading the thread, as when I bought mine from Midland Chandeliers (that well known shop for boat lighting), there was probably more 24v pumps on the shelf than 12v. This struck me as odd, and I wondered at the time how many 24v units were being purchased in error. 

 

[rusty69]

2 minutes ago, Mike the Boilerman said:

 

Curiously it crossed my mind as I started reading the thread, as when I bought mine from Midland Chandeliers (that well known shop for boat lighting), there was probably more 24v pumps on the shelf than 12v. This struck me as odd, and I wondered at the time how many 24v units were being purchased in error. 

 

You say that now Mtb! 

 

I just bought a spare last week, stuffed it under the bed without checking the numbers. Have just checked, and thankfully, it is the correct one.