Water Pump Problem

richardandros

Over the last couple of days, I have experienced a rather weird problem with our water pump. I first need to explain our water system because it's not conventional.

We had an inboard tank fitted before taking delivery of the van. The tank is filled via a normal submersible pump in the Aquaroll, controlled by a float switch in the inboard tank. Water to the van - 3 taps and the toilet - is delivered by a separate submersible pump in the inboard tank. The taps operate on microswitches.

Over the last few days, the inboard tank pump has switched itself on - at random, despite not being demanded by any of the taps. It has run for a few seconds - sometimes longer - and then switched itself off.

I have tried 'twiddling' each of the taps to make sure that none of them haven't been fully closed off but that doesn't seem to give a consistent result. I have also checked the security of the wiring to make sure there isn't an intermittent short and it all looks OK.

The other thing I have noticed is that if the pump water switch is switched off on the main switch panel - everything should be inoperative - including the toilet. However - now - the toilet flush operates even though the master switch is off.

This is pointing me towards a fault on the Thetford C260 PCB. It can't be damp related because there's no header tank on that model. That said, it doesn't explain why the toilet is still working when the master switch is off. Any ideas, anyone - plus I haven't a clue how to get to the PCB to change it anyway.

Many thanks

Richard

Cornersteady

@richardandros we had the pump switching on for a few seconds like that and it was the pressure valve/knob that simply needed turning slightly and that cured it. Btw this also happened at home as we have a pressure pump for the hot water and it was coming on at certain times, again a simple adjustment did the trick.

As to the toilet are you sure that it didn't do that (work) with the master switch off before all this?

Sorry I can't be more help. Help it gets sorted soon.

DavidKlyne

Richard

In our last motorhome that happened on a regular basis. As CS suggests it is usually a pressure problem. I imagine you have a submersble pump in your onboard tank? The pressure swtch looks like the picture below.

David

Cornersteady

https://clubtogether.caravanclub.co.uk/discussion/comment/889766#Comment_889766

@DavidKlyne that's exactly the pressure switch and turning the circular knob on the top cured the problem. I'm pretty sure the instructions were in the manual and/or online. It involves turning it while having the taps either on or off till the pressure pump switched on/off. Not very helpful - sorry.

nelliethehooker

@richardandros the toilet flush will be connected to your 12v supply, so it can be used off-grid, so could that be the reason it operates even when the master switch is off?

RedKite

You have microswitch taps, which means that you don't need a pressure switch. However nearly all taps supplied to the market have microswitches, but the caravan maker may decide not to use them, fitting a pressure switch is easier in construction because the wiring and time to connect microswitches is probably a bigger penalty in cost than the pressure switch cost. If you have a pressure switch it will almost certainly look like the one in the photo above. One point is that the water supply does not have to pass through it, although it is normally installed that way, it works just as well with one side blocked off and connected to a spur off the pumped water pipe 'T' style, and can be even cheaper to install like this, depending on the water pipe layout. If this is the case, then the cure is as above, twiddle the knob. They can be sensitive to the voltage supply, because the pump will have a higher pressure if the 12 v is up a bit, such as running from battery being charged by a mains connection, (13.8 v) or battery alone (12.5 v).

Your toilet flush button does two things. It opens a water valve, (otherwise the toilet would flush whenever you opened a tap), and it provides the equivalent of a tap microswitch, which may not be used if a pressure switch is fitted, just the same as the sink taps.

As for the master switch issue. Cant comment, thats down to the manufacturer.

If you really are using the microswiches, then I would ask if the toilet actually flushes for these few seconds, or does the pump just run ? In either case, it would point to the circuit board in the toilet.

My gut feeling is as mentioned above, you have a slightly out of optimum set pressure switch. (Somewhere in the system).

Good luck.

richardandros

Thank you all for your responses. However. - let me assure you - categorically - that there ISN'T a pressure switch in the system. I am familiar with that sort of system because that was the one fitted to our previous Bailey. Indeed, the Chief Tech at the former ALV - when I had a problem with a failed microswitch in one of the taps, actually suggested fitting a pressure switch in the system as an alternative to the fiddly job of changing the switch. I did, however, manage to change the microswitch.

I am also absolutely certain that when the master switch was off - it disabled the toilet as well. I always turn off the pump master switch when we go out and invariably when we got back and one of us dashed to the loo before I had chance to switch it on - the flush wouldn't work! Now it does.

This is why I said what was happening was weird🤔.

It's not a major problem - just annoying because I can't fathom out what's going on. I am a bit bothered about the toilet issue, though - because it obviously now has a constant 12v supply, whereas previously, it didn't.

I've tried ringing Jon from ALV but he's currently in his caravan in the nether regions of Scotland and phone reception is very poor. I'll try again today.

Thanks, once again, for your suggestions.

nelliethehooker

Hope you get it sorted out to your satisfaction @richardandros

richardandros

https://clubtogether.caravanclub.co.uk/discussion/comment/889799#Comment_889799

Thanks @nelliethehooker. In actual fact the pump switching itself on and off seems to have stopped over the last 24 hrs or so - so that points towards a tap somewhere, not previously seating itself properly and therefore not opening or closing the microswitch fully (whichever way around it is).

As for the loo - that remains a total mystery! When switching the master water pump off, previously - it disabled the inboard pump - therefore none of the taps or the button on the top of the toilet had any effect. Now - whilst switching it off disables the taps - the loo button still activates the inboard pump!

I'm baffled!

nelliethehooker

Glad to read that at least some of the problems appear to have disappeared @richardandros I guess the toilet issue is not that much of a trouble.