Jabsco water pump

[Captain Zim]

So as usual, if something is about to break, it waits until you are half way through a shower and covered in soap before deciding to give up. Seriously, why can't the pump just go whilst I'm filling the kettle? Anyway, after somehow sorting myself out, I take a look to find that the pressure switch on the bottom of the jabsco par max has been merrily leaking away and has completely rotted the connection for the power in. This is bad enough, but my thought is, this seems a bit of a design oversight where water can leak down and sit begin the plastic cover like this. Has anyone seen this before and is this normal? Also, if anyone knows where i can pick up a new 40psi switch in the London area tomorrow (preferably river lee side) I would be most grateful. Thanks

Edited December 20, 2013 by Captain Zim

[smileypete]

If the little box on the end can be removed and carefully dismantled (noting how the bits are), it probably contains a standard microswitch, which can be had for a couple of pounds from Maplins et al.

 

A tube of Fernox LSX jointing compound from the likes of Screwfix will help stop it leaking, maybe it wasn't tightened properly in the first place.

 

I thought Jabsco were pretty good.

 

cheers, Pete.

~smpt~

Edited December 20, 2013 by smileypete

[Captain Zim]

It is four years old used daily so I wouldn't necessarily say it had done badly. Just odd that the water could potentially leak into a compartment with electrical wiring. But i suppose there are only so many ways of designing something. Thanks for the advice re the micro switch. I think it is salvageable.

[smileypete]

One of these, possibly:

 

 

http://www.maplin.co.uk/p/low-cost-standard-microswitch-gw71n

 

cheers, Pete.

~smpt~

[ditchcrawler]

If the water has entered the switch I would suspect the diaphragm

[Captain Zim]

Agreed. I replaced it temporarily with a 25psi switch I had. Will see how that goes until I can get another 40. I thought I'd post once more to say that I've discovered the makers of jabsco, ITT, are actually based in Hoddesdon and Letchworth in case anyone round this way (ware) needs them. I'm not sure yet if you can turn up to collect from the factory but I checked the postmark of my last order 3 years ago (jiffy bag survived in the engine room) and that was sent from Letchworth.

 

Lastly, I know this has been posted before but can anyone give me an idiots guide to sorting out an accumulator tank. It's the cleghorn warning (jabsco) one that says it came pre-pressurised to 3 bar. I've no idea what it's at now. Thanks

[Captain Zim]

I'm hijacking my own thread with another question. I know that the answer to this is don't do it. But is it possible to adjust the cut in cut out values on a 25psi switch for the jabsco by turning the small adjustment screw? The problem I have is that this switch cuts in at 0.7 bar and I need to raise this to at least 1 bar for the morco to work.

[bottle]

The problem I have is that this switch cuts in at 0.7 bar and I need to raise this to at least 1 bar for the morco to work.

 

If it cuts in at 0.7 and the Morco needs 1 bar, then adjusting the switch will not make any difference surely the reason the Morco works is the pressure flow of the pump.

 

or

 

I have totally misunderstood how a Morco works.

 

 

edit: stupid typo, now crossed out, see following posts.

Edited December 21, 2013 by bottle

[Captain Zim]

You may be right. I don't know what the screw does in terms of adjustment. The morco needs 1 bar minimum. This pump allows the pressure in the pipes to drop to drop to 0.7 bar before kicking back in to pump up to about 1.7. So I need to adjust it, if possible, to kick in at 1.0 bar instead of 0.7 bar so that this is the minimum pressure in the pipe at any time.

 

The pressure switch I had to replace kicked in at 1.4 bar so was always well above the minimum 1bar needed by the morco.

 

This little screw is adjustable for pressure but I don't know how or what it adjusts specifically.

[MtB]

The Morco doesn't know or care what the pressure is. It is only concerned with the flow rate.

 

Try it!

 

 

MtB

[PaulJ]

I could be wrong-but does that screw not just adjust the cut in pressure and not the actual pressure of the pump? Seem to remember this when had to turn down the pressure on a pump as was to high for the prv. And you couldnt so had to get a low pressure pump. You could fit a D switch however which is a bit of a pain and cost but does make for a far more reliable system (my boat has one fitted) as is more often than not the pressure switch that plays up.

[bottle]

Thanks Mike, I should have put flow in post #8 a misleading typo sorry Captain Zim

[MtB]

Lastly, I know this has been posted before but can anyone give me an idiots guide to sorting out an accumulator tank. It's the cleghorn warning (jabsco) one that says it came pre-pressurised to 3 bar. I've no idea what it's at now. Thanks

 

Broadly speaking adjust the air pressure in it with the pump OFF and the taps open do there is no water pressure in the system.

 

Set the air pressure to match the cut OFF pressure of the pump, i.e. 1.4 bar or 21psi for the switch you are using now The pressure is not at all critical but it needs to be equal to or lower than the cut OFF pressure, so if you have is set to 3 bar still, it will have been doing bugger all since you fitted it!

 

MtB

Oh, and finally, yes the little screw adjuster thing usually raises both the cut IN and cut OFF pressure, and I suspect the only difference between your 21 psi switch and a new 40 psi switch will be the calibration set in the factory so you may as well simply adjust yours.

 

MtB

Thanks Mike, I should have put flow in post #8 a misleading typo sorry Captain Zim

 

Never a truer word than your sig, Bottle!

 

MtB

[Captain Zim]

Luckily (since I clearly don't know what I'm doing) the removed pressure switch was 2.8bar cut off so the accumulator would have been about right. I understand flow rate is different to pressure but the Morco handbook does say minimum 1bar water in. When I first set this up on a 25psi switch I got the Morco cutting out with explosive ignition. It only stopped once I changed the pressure switch. I will try it since the worst that can happen is the misses freaks out when the heater pops but I still don't understand why the morco manual says minimum 1 bar if it doesn't matter....?

[bizzard]

Agreed. I replaced it temporarily with a 25psi switch I had. Will see how that goes until I can get another 40. I thought I'd post once more to say that I've discovered the makers of jabsco, ITT, are actually based in Hoddesdon and Letchworth in case anyone round this way (ware) needs them. I'm not sure yet if you can turn up to collect from the factory but I checked the postmark of my last order 3 years ago (jiffy bag survived in the engine room) and that was sent from Letchworth.

 

Lastly, I know this has been posted before but can anyone give me an idiots guide to sorting out an accumulator tank. It's the cleghorn warning (jabsco) one that says it came pre-pressurised to 3 bar. I've no idea what it's at now. Thanks

Jabsco, Cleghorn Waring do have a counter at Icknield way Letchworth.

[Captain Zim]

Thanks bizzard. And PaulJ, that's exactly what I'm looking for. Any knowledge on exactly how it adjusts cut in pressure. This is what I need to change from 0.7 bar to 1 bar. Screw in or screw out?

[PaulJ]

Sorry Captain Zim-just went and looked at pump. It does says on pump ' Does not change Flow or Operating Pressure' but adjusts shut off pressure only and not cut in.

Oh and its a Shurflo pump too so MtB may be right...

[Captain Zim]

Thanks for looking and MtB sincere apologies, I completely missed your bit about the screw. Nice one. Here goes...

[smileypete]

On the shurflos it's screw in to increase both cut in and cut out pressure.

 

Don't wind it it tooooo far or there's a risk the pump motor will stall before it cuts out, and the motor will get rather hot!

 

The Morco may well be happy with the lower cut in pressure so worth a try first.

 

cheers, Pete.

~smpt~

Edited December 21, 2013 by smileypete

[PaulJ]