Bilge pumps, again

Tim M · 08 March 2008, 07:59

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 · 08 March 2008, 08:06

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 · 08 March 2008, 08:12

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

Poly · 08 March 2008, 08:39

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 · 08 March 2008, 08:42

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

Tim M · 08 March 2008, 09:07

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 · 08 March 2008, 09:18

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 · 08 March 2008, 09:22

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 · 08 March 2008, 12:09

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 · 08 March 2008, 15:50

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

hobbit555 · 08 March 2008, 16:19

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

jwalker · 08 March 2008, 16:56

Quote:

Originally Posted by Hightower

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.

Or just crack em open and have a look.

The broken ones have suffered mechanical stress of some sort. Do they bend as you screw them down?

Searider · 08 March 2008, 17:07

Low voltage at the pump?

Have you checked the voltage at the pump when its running?

Low voltage might cause the motor to run hotter?

Hightower · 08 March 2008, 19:07

Quote:

Originally Posted by jwalker

Or just crack em open and have a look.

The broken ones have suffered mechanical stress of some sort. Do they bend as you screw them down?

I was thinking more of a play on the Manufacturers sympathys and that there might be a possibility of having one or two new ones back in return as well as them finding out that the problem was. It's also very important for the manufacturers to find these problems in the field as they might be able to make a better product in the future.

Chris · 08 March 2008, 19:59

I have had one of the Rule electronic auto pumps since lastt January and although my boat does not sit on a mooring so the pump does not get used as much it has been faultless so far and I have frequesntly seen it clearing water that is full of sand or mud from the deck.

BTW the rule auto works by the pump automatically running for a couple of seonds every 30 secs I think it is. If there is water present the load on the motor trigger the pump to continue pumping until the water has cleared and the load on the motor goes.

Clever stuff really!

Tim I really think you have some kind of electrical problem.

My suggestion would be to run a fresh set of cables and possibly a new switch as well.

Are you running the dual rocker switch option on the Rule auto which allows you to turn it on to auto or manual?

Chris

nik · 10 March 2008, 01:09

Quote:

Low voltage might cause the motor to run hotter?

No, less voltage = less heat.

Nick.

JABS · 10 March 2008, 07:43

Quote:

Originally Posted by nik

No, less voltage = less heat.

Nick.

No.

On a motor, lower voltage equals slower running which equals lower back EMF equals higher current equals more heat.

Chris · 10 March 2008, 09:31

Quote:

Originally Posted by JABS

No.

On a motor, lower voltage equals slower running which equals lower back EMF equals higher current equals more heat.

absolutely ! a motor will try to draw the current it needs so if there is a blockage and its not getting as much power as it wants then it can cause overheating of both the pump and the wiring.

Simon B · 10 March 2008, 11:29

Quote:

Originally Posted by Tim M

1 "disintegrated" - the red top part came away from the white body.

Is the red bit on top with the auto ones?

I'd send half of the scrappers back to Rule and half off to a local uni or technical college as a "project"

We've had a non auto 4000gph for 4 years with no problems other than a fuse holde in the console failing.

Hightower · 10 March 2008, 19:08

Quote:

Originally Posted by Chris

absolutely ! a motor will try to draw the current it needs so if there is a blockage and its not getting as much power as it wants then it can cause overheating of both the pump and the wiring.

Well if that's the case check that the wiring run against the size of cable so that you don't get too much Voltage drop for the Current needed.