Whale water pump stopped working

[TheCheltenham]

Our Whale Watermaster has stopped on our Bailey 450/5. We're on the first day of a 14 day holiday.

The 10 amp fuse was blown. I've replaced that. Nothing. No sound of it trying to pump at all. So it's not the seal or something not working. It's dead. I guess it could be:
1) The outside pump itself
2) The socket and internal side
3) The internal electrics

What could I do to check any of it? I could probably get a replacement pump, but the socket and internals are too much work while were away.

I'll put the details I have from the paperwork in the comments below.

Thanks so much for your thoughts and advice.

 

[Jcloughie]

My first move would be to remove the pump and see if there is 12 volt across the terminals when water is called for.

If you have 12 volt it points to a blown pump.

And/or. Wire the pump directly to the battery to see if it works.

John

 

[ProfJohnL]

I presume you have a submersible pump. I agree with JCLoughie's suggestion, but for future reference one of the most common causes for a pump failure is allowing the pump to run whilst the water container is empty, or for any reason the pump does not shut off when the taps are closed.

The reason this is damaging, is the pump consumes up to 100W peak power some of which it converts into heat. It relies on the flow of water through the pump to keep it cool. If the flow of water is blocked the temperature of the pump will begin to rise, It will rise even more quickly if the water carrier is empty. The temperature can rise far enough to soften the plastic of the pumps motor housing which can distort and damage the motors water seals. When water is available it can get into the motor and when that happens the motor will fail quite quickly.

You need to know if your pump is controlled by microswitches in every tap (a micro switched system) or by a single pressure switch (a pressure switched system)

If its a micro switched system, then whenever a tap is just cracked open a micro switch in the taps body closes and completes the power circuit for the pump. If a micro switch fails to break the circuit when the tap is closed, the pump will run continuously. You need to check every tap including the shower water valves are turned off completely. I have had to point this out on a number of occasions to folks whose shower had a mixer tap and a trigger on the shower head.

If its a pressure switched system, the pump runs to increase the pressure in the pipe work and when it rises far enough the pressure switch interrupts the pump circuit and turns it off. When you open a tap, the pipe pressure is released and the pump turns on. if your tap is only open a little, the pump may repeatedly switch on and off as it may be able to create more pressure than the cracked open tap releases. That is normal behaviour. Normally in a pressure switched system the pump will stop running in under 5 seconds from fully closing the tap.

If the pump takes more than a few seconds to turn off after the tap is closed, it suggests the pressure switch may need to be adjusted - the instructions to do this should be in your caravan handbook or they can be found on the Whale pumps (Munster Simms) website. This is voltage dependant which can change if you switch from using an mains Electrical Hook Up (EHU) to just caravan battery.

However if the pump continuously pulses even when the taps are closed, it means you have a water leak somewhere. In some cases there is no visible leak, in which case its probably debris in the non return valve which is usually fitted into the pressure switch. Sometimes these can be repaired by dismantling the pressure switch and cleaning the parts before reassembling it. Other wise it may need a replacement pressure switch .

 

[audiorob]

Might be worth taking the strainer off the submersible pump and while disconnected from the caravan ensure the impeller can rotate with a small screwdriver.

 

[IanB1485]

have to disagree with prof john about the 100W consumption (8.3 amps ) all the common submersible pump I've tested at locked rotor have only ever pulled a little over 3 amps and when running dry -i.e no load about 1.8 amps. the rest of his analysis is accurate

 

[Buckman]

Generally Whale pumps are extremely reliable so there may be another cause. Maybe you can test the pump at a third party source to determine if it is the pump? IanB should be able to advise.

 

[ProfJohnL]

have to disagree with prof john about the 100W consumption (8.3 amps ) all the common submersible pump I've tested at locked rotor have only ever pulled a little over 3 amps and when running dry -i.e no load about 1.8 amps. the rest of his analysis is accurate

Specifically I wrote "the pump consumes up to 100W peak power " and I know that sound a lot but pumps use electric motors and the starting current all-be-it for normally a fraction of a second can peak out at 100W. That is why pump fuses are typically rated at 10A to cover the inrush current. the running typically 3 to 4A when things are working correctly, but if the pumps flow is blocked, or the impeller is jammed, the pump will increase the current it draws.

During the 1990's I was employed and part of my responsibilities was to test various different appliances to assess their reliability and failure modes for clients. We tested virtually every make and model of caravan submersible pump to destruction we had a rig that ran pumps on a cyclic programme for weeks/months to mimic typical caravan usage. We monitored flow rates against a 2 metre head (to mimic the height of a shower head above an external water container, and current draw. and of course time to significant change or failure. We also ran pumps dry and with the water flow blocked to simulate possible scenarios as I describe in my previous posting.

 

[TheCheltenham]

Thank you for such comprehensive answers, exactly what I needed. I will see if the pump impeller can rotate, see if I can test it elsewhere and then check thr voltage.

I think it's a pressure switched system.

Thanks again.

 

[Dustydog]

Indulge this old dog😉.
We are talking about an on board pump not a submersible as suggested ?
Whatever it is I believe the same principles apply as described by the Prof.

 

[ProfJohnL]

Indulge this old dog😉.
We are talking about an on board pump not a submersible as suggested ?
Whatever it is I believe the same principles apply as described by the Prof.

The op stated:-
"
The 10 amp fuse was blown. I've replaced that. Nothing. No sound of it trying to pump at all. So it's not the seal or something not working. It's dead. I guess it could be:
1) The outside pump itself
2) The socket and internal side
3) The internal electrics"

Which I took to mean an external pump.

 

[Buckman]

I presume you have a submersible pump. I agree with JCLoughie's suggestion, but for future reference one of the most common causes for a pump failure is allowing the pump to run whilst the water container is empty, or for any reason the pump does not shut off when the taps are closed.

Many modern caravans now have an inbuilt cut off that shuts down the pump if either the onboard or external water supply fails. I am not sure which year the OP's caravan is, but this may be a heads up for others with new caravans.