Water pump continues to run after tap closed

[klaatu]

The water pump on our six month old Globecar Summit 640 has started to occasionally continue to run after a tap has been closed, either the kitchen tap or bathroom tap. This has started happening approximately once a day.

The pump is operated by microswitches rather than by pressure, and is submersed in the water tank. As it happens with both taps, I’m pretty sure it’s not a microswitch problem (but I accept that it might be). I’m not sure what make of pump it is.

Turning the tap on and off for a couple of minutes eventually causes the pump to stop. As an experiment, today I tried doing nothing to see if it would stop on its own, but it didn’t after several minutes.

Turning the water pump off at the control panel doesn’t stop the pump when this issue occurs, but it does normally stop the pump operating when the taps are opened at other times.

Any suggestions as to what might be causing this?

 

[Phill D]

Turning the water pump off at the control panel doesn’t stop the pump when this issue occurs,

that to me suggests its getting an additional feed from somewhere.

 

[klaatu]

that to me suggests its getting an additional feed from somewhere.

Yes, my thoughts too, a short of some kind, but why it’s only activated by turning a tap on, and why turning the tap on and off causes it to eventually stop baffles me.

 

[klaatu]

Perhaps a relay is involved, and the relay is sticking?

 

[Phill D]

i guess thats possible but you would think the panel overides everything

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[andy63]

you could do with a wiring diagram .. just to see exactly how the switching occurs .. and if there are any relays in the wiring that could be sticking..
my initial thoughts
Andy
edit
I see you've already considered that

 

[klaatu]

i guess thats possible but you would think the panel overides everything

Yes, I find that odd.

 

[klaatu]

you could do with a wiring diagram

Yes, that would be handy!

 

[Wagoneer]

I guess the wires from the micro-switched taps feed to a common relay which triggers the pump. This setup avoids high pump currents passing through the micro-switched taps (and leading to their early demise).

Lenny HB modified his latest Hymer to this system. Perhaps Globecar uses a similar system.

Might be worth tracing the wires from the taps to check if they end up at a relay, possibly in the vicinity of the pump.

 

[TheBig1]

search for a relay near the wire that feeds the pump

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[Lenny HB]

Never seen a relay fitted as standard in a micro switched system. I always fitted a relay myself in every Motorhome & caravan I've had.

Dooes the problem only happen with one tap?
As the mico switches are often normally closed contacts (latest Reich taps are) and the cam in the tap holds the switch open in the tap closed position. It could be something broken in the tap or a faulty switch.

 

[TheBig1]

could also be a damaged wire in the body of the tap, seen a few of those but this, if I am reading right affects 2 different taps

 

[klaatu]

could also be a damaged wire in the body of the tap, seen a few of those but this, if I am reading right affects 2 different taps

Yes, initially I thought the same as it was only the bathroom tap which started the problem, but then yesterday it started with the sink tap too.

 

[Lenny HB]

could also be a damaged wire in the body of the tap, seen a few of those but this, if I am reading right affects 2 different taps

That would cause the tap not to turn on.

 

[Lenny HB]

Yes, initially I thought the same as it was only the bathroom tap which started the problem, but then yesterday it started with the sink tap too.

Wouldn't surprise me if more than one tap is faulty, if you have ever taken one apart to repair it you will know what a load of crap they are..

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[Allanm]

Do you have a shower tap? If so, does it still happen if you use that?

 

[mikebeaches]

Our van - Rapido V68 - may have a similar set up.

There is some sort of pressure switch/micro-switch outside the fresh water tank that controls the water pump. When the van hasn't been used for a while I often have to tinker to adjust the setting. Otherwise the pump just keeps running, as you've described.

The micro-switch has a small wheel on it to adjust the setting.

It always strikes me as a bit random, but I can normally set the balance so the taps work OK, and the pump switches on and off when it should.

 

[klaatu]

Do you have a shower tap? If so, does it still happen if you use that?

We do, but we have been mainly on sites for the last two months, and we are part of that weird group of people who use the site showers when available (and not manky), so the shower hasn’t been on for a long time.

So far the problem hasn’t occurred with flushing the toilet either.

 

[mitzimad]

For what they cost id change both microswitches see if that stops the problem if i doesnt youll have two spares

 

[jezport]

Or disconnect the micro switches and add a temporary manual switch and see how it goes.

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[Silver-Fox]

Why do they make these things so bloody complicated.

A simple pump that works when the pressure drops, what’s not to like.

Sorry no help though ?

 

[jezport]

Why do they make these things so bloody complicated.

A simple pump that works when the pressure drops, what’s not to like.

Sorry no help though ?

Because you are then running a permanantly pressurised water system which has a totally different set of problems. Personally I dont know which I prefer.

 

[Silver-Fox]

Because you are then running a permanantly pressurised water system which has a totally different set of problems. Personally I dont know which I prefer.

You know if you have a leak though ?

With micro switches you could still have a leak and not know.
Just a thought.

 

[Lenny HB]

Because you are then running a permanantly pressurised water system which has a totally different set of problems. Personally I dont know which I prefer.

Likewise, I keep saying if another micro switched tap gives problems I'll fit a pressure system. Then I think about all the problems I had with caravans with pressure switches.

 

[jezport]

You know if you have a leak though ?

With micro switches you could still have a leak and not know.
Just a thought.

As the system with micro switches is unpressurized a leak is highly unlikeley and if it does happen the pump wont empty the whole tank at high pressure into your van. Pros and Cons !

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[klaatu]

I have found a wiring diagram for the CBE distribution unit and there is indeed a relay involved, it is on the distribution unit circuit board. I can now hear it clicking when I operate a tap. I now need to confirm that it is this relay at fault when the problem occurs again - I’m betting it is.

Thanks for all the replies so far. I’ll update when I know more.

 

[Silver-Fox]

As the system with micro switches is unpressurized a leak is highly unlikeley and if it does happen the pump wont empty the whole tank at high pressure into your van. Pros and Cons !

I was thinking it will leak whilst the taps are being used but you wouldn’t know ?

 

[jezport]

I was thinking it will leak whilst the taps are being used but you wouldn’t know ?

may but as its not under pressure when the tap is open its unlikely to leak much

 

[funflair]

We have had pressurised systems with Surflo pump for 20 years now, in that time we have had a small leak on the pumps three times, every time easily fixed by stripping and cleaning.

Martin

 

[Silver-Fox]

may but as its not under pressure when the tap is open its unlikely to leak much

?

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