sure-flo pump problem

[frahkn]

A few months ago my Sureflo cold water pump failed - I had a spare so replaced it and kept the old one, intending to look at it later. I asked a question about it, on this forum, at the time.

 

Yesterday the new pump failed and on looking at it, the live input wire had failed just where it plugs into the pump. The plastic was burned at the end, where it had been arcing.

 

I replaced the manufacturers terminal with one of my own and so far all is well. But this led me to looking at the old pump at last. The same terminal showed the same signs of burning!

 

I don't think there is a design fault (no one has ever mentioned one) so can anyone suggest something that I might have done to lead to this problem? I should say that the pump is mounted vertically in a dry space.

 

Thanks.

 

 

This is a poor signal area so I may be slow in coming back to this.

[frangar]

Possible voltage drop in the feed to the pump leading to the pump drawing more current than designed....I take it there is a fuse in the supply cable of the correct rating?

 

Cheers

 

Gareth

[Phil Ambrose]

As Gareth has suggested, I would hazard a guess that the pump is a long way from the batteries, is the cable of sufficient size for the job?

Phil

[frahkn]

Thanks both.

 

The pump is indeed about 50 feet from the batteries but there is a fuse on the fuse board and another in line. Both are 10 amp.

 

Three issues occur to me a) As far as I know there was no problem for the previous owners - who were live aboard (I am not) The manufacturers wire (about 1 foot of it, leading to the burned connection) is much smaller cross section than the boat supply cable to which it is connected - would the overheating not take place at the boat/manufacturer junction? c) the boat is fitted with twin pumps (both the same model sure-flo) one for the hot water and one for the cold, the hot water pump is mounted horizontaly and has never failed.

 

Thanks.

[smileypete]

If it's a male/female plug in crimp connection, it could be the crimp on either side that's causing the overheating.

 

For good crimp connections best use decent quality BS4579/BS4G178 terminals in the right size, with a reasonable ratchet crimper. If tools for a good crimp aren't available, next best might be terminal blocks with bootlace ferrules on the bare ends of the cable.

 

The cheaper Shurflo pumps are usually intended for caravans and motor homes, and may not have tinned stranded wire suited to the harsh conditions sometimes found in the darkest recesses of a bote.

 

cheers, Pete.

~smtp~

Edited September 20, 2014 by smileypete

[frahkn]

Thanks smileypete.

 

It is the manufacturers connection which failed. The pump body has a spade terminal but the wire terminated in a connector covered by hard white plastic, partly melted and burned. I cut this off and replaced it with my own terminal, which is working so far.

 

My main concern is that the problem with the old pump now seem to have been the same.

 

I will pass a chandler tomorrow and am thinking of picking up a pump so as to have a spare - which brand would you suggest?

 

Thanks

[smileypete]

Just about anything is better than a Shurflo these days it seems.

 

Something with about 10lpm flow and around 2 bar/28psi cutoff should suit most people, couple of examples are:

 

Jabsco Par Max 2.9 11lpm 25psi (31395-0292 for 12V)

Whale Watermaster 12lpm 30psi (FW1214 for 12V)

 

That said the Shurflo ones are pretty fixable, a trawl of the forum will likely pick up the common problems and cures, but poor factory crimping is a new one on me!

 

cheers, Pete.

~smpt~

[Paul C]

2nd vote for Jabsco Par Max.

[frahkn]

My own connection is working so far but I bought a spare pump just in case - a Whale Watermaster (thanks smileypete).

 

One thing I have noticed is that the pump comes on when no taps are working, more often than it used to. And when using a tap, the pump doesn't just run and stop. It ends in a series of short stutters instead. I am pretty certain that I don't have a leak so I suppose the pressure in the accumulator? needs increasing. I will look at this once I get a pump.

 

Might this cause the overheating?

 

Thanks.

Edited September 22, 2014 by frahkn

[smileypete]

My own connection is working so far but I bought a spare pump just in case - a Whale Watermaster (thanks smileypete).

 

One thing I have noticed is that the pump comes on when no taps are working, more often than it used to. And when using a tap, the pump doesn't just run and stop. It ends in a series of short stutters instead. I am pretty certain that I don't have a leak so I suppose the pressure in the accumulator? needs increasing. I will look at this once I get a pump.

 

Might this cause the overheating?

 

Sounds like it's worth checking, they have a schrader (sp?) valve under a small plastic cover on top.

 

Also the water pump must have a strainer before the inlet to catch any debris from the tank, or it can bung up the pressure switch causing all sorts of problems.

 

Several methods for checking accumulator in these topics, last looks easiest if you have a suitable gauge.

 

http://www.canalworld.net/forums/index.php?showtopic=64181#entry1242776

http://www.canalworld.net/forums/index.php?showtopic=67658#entry1337817

http://www.canalworld.net/forums/index.php?showtopic=69282#entry1378367

 

The accumulator is usually between pump and calorifier inlet or a nearby non return valve, sometimes there's an expansion vessel for the calorifier as well (or instead? ).

 

Any expansion vessel is usually between calorifier outlet (or that non return valve), and the hot taps and needs a different method to set the pressure.

 

cheers, Pete.

~smpt~

Edited September 22, 2014 by smileypete

[frahkn]

OK - here is an update.

 

I got a footpump with a pressure gauge. Also noticed that the accumulator says "20 psi" on its label. The water pump is 30 psi and 11 litres per min.

 

With the power on but no tap running the gauge showed 45 psi; with the power off it showed the same; when a tap was opened the pressure declined to nil!

 

I then pumped it up to 20 psi and turned the power back on. Opening and closing a tap, the pump comes on at about 20 psi, the goes off but comes back on in a series of short stutters right up to 45 psi. So I have the situation where the cut in pressure seems to be 20 psi but the pump then goes off and come back on at higher pressures.

 

Overall the repressurisation has reduced, but not eliminated the stutter and I think it is this stutter which is causing the overheating of the connection.

 

Any solutions or ideas for further tests?

 

I am stumped.

 

Thanks.

[llutherr]

Jabsco.

[smileypete]

Sounds like it may be a pressure switch issue, best try the new pump.

 

If you're up for stripping the Shurflo down they're pretty fixable, there's quite a few previous topics to be found on it via the search facility.

 

Easiest gauge to use could be a £4 digital one off Ebay, leave the tap at a trickle and watch the pressure as the pump cycles in and out.

 

cheers, Pete.

~smpt~

Edited September 26, 2014 by smileypete

[FORTUNATA]

Just about anything is better than a Shurflo these days it seems.

 

Something with about 10lpm flow and around 2 bar/28psi cutoff should suit most people, couple of examples are:

 

Jabsco Par Max 2.9 11lpm 25psi (31395-0292 for 12V)

Whale Watermaster 12lpm 30psi (FW1214 for 12V)

 

That said the Shurflo ones are pretty fixable, a trawl of the forum will likely pick up the common problems and cures, but poor factory crimping is a new one on me!

 

cheers, Pete.

~smpt~

This is one of my new hobbies. People keep chucking away their pumps and I enjoy fixing them. I already have one of these pumps that's broken and ready to be tackled. Really they are a good pump but lately my own is a bit noisy. I've now got so many pumps I may start selling them on ebay.

[Paul C]

This is one of my new hobbies. People keep chucking away their pumps and I enjoy fixing them. I already have one of these pumps that's broken and ready to be tackled. Really they are a good pump but lately my own is a bit noisy. I've now got so many pumps I may start selling them on ebay.

 

I hope you have thought it through, people don't appreciate buying things which stop working soon after purchase, on eBay. Hopefully you can fix them well enough that they'll last before the time period for leaving feedback runs out....

[FORTUNATA]

Sounds like it may be a pressure switch issue, best try the new pump.

 

If you're up for stripping the Shurflo down they're pretty fixable, there's quite a few previous topics to be found on it via the search facility.

 

Easiest gauge to use could be a £4 digital one off Ebay, leave the tap at a trickle and watch the pressure as the pump cycles in and out.

 

cheers, Pete.

~smpt~

Not sure yet how much a new diaphragm costs. The one I'm looking at now has some wear around the diaphragm edge. It was also clogged with bits of silicon as s omebody went wild with a tube. For some reason also, there seems to be no way yet of manually priming the pump - seems internally air-locked. I spent some time unclogging the flap valves but clearly more in depth work is now required. You wouldn't believe the amount of pumps I'm getting from despairing boaters. I thought of a name for my e-water pump company LTD. "Clapped out Pumps Dot Com".

[smileypete]

Not sure yet how much a new diaphragm costs. The one I'm looking at now has some wear around the diaphragm edge. It was also clogged with bits of silicon as s omebody went wild with a tube. For some reason also, there seems to be no way yet of manually priming the pump - seems internally air-locked. I spent some time unclogging the flap valves but clearly more in depth work is now required. You wouldn't believe the amount of pumps I'm getting from despairing boaters. I thought of a name for my e-water pump company LTD. "Clapped out Pumps Dot Com".

 

I'd not waste too much time on a 'basket case' though , sounds like there's plenty of others!

 

To give them a bit of a re-con could clean the pressure switch internals and renew the micro switch, check the 'wobble bearing' and replace if worn, clean the diaphragm and re-seal with a smidgen of Fernox LS-X, renew the crimp connections if poor with decently done ones, then clean pump and test for a while.

 

Doesn't take long with a bit of practice or cost much. If offering a small guarantee for extra, would be wise to engrave/UV mark the main bits just in case.

 

cheers, Pete.

~smpt~

[FORTUNATA]

 

I'd not waste too much time on a 'basket case' though , sounds like there's plenty of others!

 

To give them a bit of a re-con could clean the pressure switch internals and renew the micro switch, check the 'wobble bearing' and replace if worn, clean the diaphragm and re-seal with a smidgen of Fernox LS-X, renew the crimp connections if poor with decently done ones, then clean pump and test for a while.

 

Doesn't take long with a bit of practice or cost much. If offering a small guarantee for extra, would be wise to engrave/UV mark the main bits just in case.

 

cheers, Pete.

~smpt~

I've found with these pumps they tend to p*** either air or water from the casing joint. This happens when the diaphragm is worn or distorted at the edge. So, now I may see if I can find a diaphragm. The repair kits are not cheap so I'll see if I can find just a diaphragm and then see if the pump can be used again as normal.

The diaphragm acts as a gasket as well so if it's distorted, getting an air seal is almost impossible. Neither does silicon work that well but breaks up as I found when I looked at the flap valves.

[smileypete]

Use some Fernox LS-X, not normal silicone. Put sparing amount on near edges of side facing pump chamber, tighten till housing is just showing a tiny gap, then wait til set and then tighten fully.

 

cheers, Pete.

~smtp~