Multiple water pump failures

[vanboosh]

Has anyone experienced multiple water pump failures? My neighbour has had 3 pumps die in in the last 6 months… 

[BWM]

Either a load of rust or similar contaminating the water feed from the tank or more likely an erratic power supply to the pump.

[Tony Brooks]

A large hire fleet I know of suffered such failures on a few boats. It turned out to be undersized cables causing volt drop so the motors ran too slowly and that caused them to draw too much currant so they burned out. So in response to your question is it a motor failure or does it run but not pump water.

 

Edited to add it might be caused by trying to run it with all but totally discharged batteries not allowing the motor to get to the design speed.

Edited November 10, 2022 by Tony Brooks

[MtB]

7 minutes ago, Tony Brooks said:

A large hire fleet I know of suffered such failures on a few boats. It turned out to be undersized cables causing volt drop so the motors ran too slowly and that caused them to draw too much currant so they burned out. So in response to your question is it a motor failure or does it run but not pump water.

 

 

Or better still for the OP to get the neighbour to come on here and post the details directly, rather than doing it by Chinese whispers.

 

 

[Tony Brooks]

3 minutes ago, MtB said:

 

 

Or better still for the OP to get the neighbour to come on here and post the details directly, rather than doing it by Chinese whispers.

 

 

 

I agree because this may well take a number of diagnostic questions being answered to come to a satisfactory conclusion. It is always more difficult trying to do it second hand.

[vanboosh]

1 hour ago, BWM said:

Either a load of rust or similar contaminating the water feed from the tank or more likely an erratic power supply to the pump.

Don’t think it’s rust - newish boat with stainless tank. How would we check for erratic power supply? Just hold a multimeter on it and see if it fluctuates? 

1 hour ago, Tony Brooks said:

A large hire fleet I know of suffered such failures on a few boats. It turned out to be undersized cables causing volt drop so the motors ran too slowly and that caused them to draw too much currant so they burned out. So in response to your question is it a motor failure or does it run but not pump water.

 

Edited to add it might be caused by trying to run it with all but totally discharged batteries not allowing the motor to get to the design speed.

This sounds like a possibility! Motor failure rather than not pumping water. 

I’ll send him the forum link and see if he can reply to clarify things. 

Edited November 10, 2022 by vanboosh

[Alan de Enfield]

3 minutes ago, vanboosh said:

This sounds like a possibility! Their batts also does not too long ago, so could be connected. Motor failure rather than not pumping water. 

 

Check the cable for volt drop, or find out what size it is, how long (from the battery) it is and what current the pump draws.

[ditchcrawler]

Put a multimeter on the motor terminals set on voltage and see what the voltage does when the pump is running and report back

[Tony Brooks]

55 minutes ago, vanboosh said:

Don’t think it’s rust - newish boat with stainless tank. How would we check for erratic power supply? Just hold a multimeter on it and see if it fluctuates? 

This sounds like a possibility! Motor failure rather than not pumping water. 

I’ll send him the forum link and see if he can reply to clarify things. 

 

Measure the voltage at the batteries with the motor RUNNING & note it

 

Measure the voltage at the connection where the boat's wiring is connected to the pump wiring with the motor running and note.

 

Subtract the second from the first and you will have the volt drop on the circuit. I would not want to see any more than 0.3 to 0.5 volts for a 12V boat. The lower, the better.

 

If there is a high volt drop it needs more investigation because it could be a fuse, switch or terminal problem.

 

 

[Sea Dog]

3 hours ago, vanboosh said:

My neighbour has had 3 pumps die in in the last 6 months… 

Of course, it may also help to know the make/model of the pumps concerned. If your neighbour is replacing quality pumps at an alarming rate, the fault is indeed likely to lie in the boat's system. On the other hand...

[magnetman]

I wonder if it was something like a Shurflo pump with no accumulator. They do a lot of work on a residential craft and the brushes are not all that huge. I'm pretty sure there are some dodgy chinese pumps with shurflo branding which are even worse than the real ones.

 

Still it does seem odd to only get two months.

 

Assuming the OP means 3 consecutive failures rather than having several different pumps on the boat.

 

Cheap pumps are also available without branding of course.

Edited November 10, 2022 by magnetman

[frahkn]

9 hours ago, vanboosh said:

Has anyone experienced multiple water pump failures? My neighbour has had 3 pumps die in in the last 6 months… 

When I first bought the boat (second hand) I changed 4 Shurflo pumps in less that a year. Having changed to Jabisco I no longer have any problem.

[blackrose]

You went through 4 pumps in a year? I had a new Shurflo pump leak after 4 years which I repaired by fitting a new pump head for 25 quid. When it leaked again a year later I realised they were crap and changed to Jabsco.