Bilge pumps, again

[Tim M]

I have am having terrible problems when it comes to bilge pumps. I keep fitting new ones, only to have them last a week and then blow up/fall apart. Some memorable failures have included:
3 Rule fully automatic pumps - all have lost their automatic feature. 1 "disintegrated" - the red top part came away from the white body. Another just stopped working all together.
Countless non automatic Rule 500pgh (coupled to float switch). All have broken in some way or other. Most of the time they just don't work any more. One very memorable one was when Jimbo and I were washing the boat and the pump started steaming, it continued to do so for about a minute after I turned it off. That was a write off.
I thought it must be Rule pumps that were the problem, so I started experimenting.
I tried a Wale, that lasted about about 3 weeks before stopping. That was followed by a Johnson. Again, just stopped working after several weeks.
Last week I bought a nice looking pump (cant remember what its called but its pretty substantial) off another ribnet member. That lasted 7 days before dieing. Strangely he has a similar one installed in his rib and its going strong after several months.

Where am I going wrong??? I've had alsorts of theories. At first I thought that if petrol went near the pump that would be the problem, but no petrol has been anywhere near the majority of these pumps. Then we thought it was Turtlewax shampoo that I clean the boat with. I gave up using that and 2 pumps have gone since. The pumps are installed correctly, and work fine to start off with....

Someone has suggested to me that maybe I have some sort of electrical problem, in that when the engine is running maybe it causes some sort of voltage spike to kill the pump. Surly, since the pump runs off the battery, the battery would absorb any sort of spike?

Any suggestions please - I need to get this sorted as its costing me a fortune!

[C2 RIBS]

Yep , help Tim as his boat gets wet and I know having been ankle deep last weekend when the last failure occurred on an instructors course and I can support Tim nothing but water was in the boat(ok bar us!)

[Tony]

Hi Tim
Have the pumps cracked? I had two do that..
Also you could put a fuse in between the battery and the pump to see if it blows?
hope this helps
Tony

[Polwart]

tim,

here are some ideas that spring to mind:

Are you running your pumps dry? (ie. when no water is there) - I believe they don't like that.

Is there any constriction in the output tube that is making the pumps work harder?

Is your pump just under specced for the job so it is running much more than it should?

I did read somewhere about cheap fake pumps from china which look like the genuine article but have much smaller motors - but can't believe that could be the problem for all of yours.

I would be suspicious about an electrical fault though - should be easy enough to check the voltage and current with the engine on and off - and see if there are "in spec".

Might be worth sending a few back to rule. At least they should be able to tell you if it is "chemical", "wear" or "electrical".

Failing that get a manual pump and make the crew earn their trip!

[Hightower]

Have all the bilge pumps that you've been using been Auto ones with built in floats/mechanisms?

[Tim M]

Hi Ian. Didn't realise you were on the instructors course. Sorry about the wet feet!

In answer to some of the above:

Yes several of them have cracked. (Bilge pumps seem to be made of really crap plastic)

The pump is fused.

The fully automatic rule ones say they are run dry-proof. The non auto ones are linked to a float switch which means they cut out when there is still about an inch of water in the bilge.

Water-flow doesn't appear to be restricted - I am using the correct diameter hose, and it only has to pump the water about 3 ft before it goes out the back of the boat.

Andy, the rule ones have some sort of wizardry inside which works out if there is water present, so no float switch. As I said I have used pumps with a separate float switch, and of course that one from last week had a float switch.

It's baffling! I'm just about to go and buy another. Anyway want to place bets on how long it lasts?

[Hightower]

Check the voltage at the business end with the engine running before you go buy another one. Make sure it's within the recommended range. I guess that there are no other electrical quibbles onboard.

If you've made a collection on dead pumps, I would suggest sending them off to the manufacturers with a letter explaining the problems you're having and get them to analizse the sample ones to see if they can suggest what's happening. At worst you'll have to pay a bit of postage, at best you might get the answer you're looking for, with some new pumps mailed back too.

Does the coding say they have to be Auto pumps? Can you use a manual one nstead? How about a hand bilge pump as a back up.

[DGR]

That sounds very odd - but if all the pumps from a load of different manufacturers are dying regularly, then I doubt it is the pump.

I'd check that the installation is correct (pump heights, pipe diameters etc) - although it sounds like you've got that side of it covered - the only other common feature is the power supply. I'd check and double check the voltage - if you've got 2 batteries, make sure that they aren't accidentally being supplied with 24V - if they are set to run when the isolators are off, double check the voltage with them on - and put a meter across it to see what's happening when you are running the engine.

I've got 4 rule auto bilge pumps on mine - 2 on deck, and 2 in the engine box. The deck pumps are on pretty much 100% of the time for 6 or 7 months a year, and last summer both deck pumps failed within 2 weeks of each other after 3 years of reliable service. They are the only bilge pumps I've ever used - but have no issues with them!!

D...

[codprawn]

My first Rule auto packed up after about 4 months - the replacement has been fine for 18months and works harder than most with the weather we get!!!

You mention them cracking - how are they mounted? Mine is just stuck to the hull with some sort of sealant - it's crude but it gives a certain amount flexibility to absorb vibration etc.

Another possibility is do you get a lot of sand coming on board? I doubt they would like that much!!!

[hobbit555]

Sounds electrical to me

Is there any electrical circutry in the pumps check the polarity

also which way round is the earth on the system

just some of the problems I have encountered