Changing a bathroom shower tap microswitch on an old Hymer644 (1998)

[Geoff Powell]

Hi,
I'm new to motor homes and have bought a Hymer 644 (1998). The bathroom has a tap/shower on which the microswitch has gone, first open circuit and now short circuit. My problem is I don't seem to be able to remove the cover from the tap to identify and change the micro switch. (Photos attached) has anyone any ideas as I'd rather not have to buy a complete new shower tap. Thanks, Geoff

 

[ianp]

Need clearer photo's Geoff!

 

[me you and pogo 2]

Hi Geoff,
We had a similar problem with our shower tap, it trickled and there wasn't much pressure. We couldn't get to it or remove it easily.

If yours is the same problem this how we fixed it.

When the mobile motorhome repairer man came he looked at it and gave us two choices;

1. fit a water pressure switch in the moho system for about £50 or
2. repair the micro switch for about £25 (I seem to recall)

Due to the age of the moho it's possible the other micro switches might go.

Option one would ensure that all the taps would continue to work even if the micro switches failed later. (I am informing you what he told me).

Option two would be to repair the switches each time they fail.

We went for No1, he fitted a water pressure switch (a Whale pressure costs about £25) in the plumbing system at the beginning of the pipe work just as it comes out of the fresh water tank.

I hope this helps.

Regards
Dave

 

[Rollin]

a water pressure switch (a Whale pressure costs about £25) in the plumbing system at the beginning of the pipe work just as it comes out of the fresh water tank

that's an interesting idea, so does the pressure switch link up to the existing pump or does it have its own pump built-in?

 

[pappajohn]

that's an interesting idea, so does the pressure switch link up to the existing pump or does it have its own pump built-in?

Either, depending on the pump.
Having micro switches usually means a submersible pump in the tank so a stand alone pressure switch is fitted in the tanks outlet pipe and is wired to the pump.
Open any tap, the stored pipe pressure drops, the pump turns on.
Tap off, pressure builds in the pipes and turns off the pump.

An 'out of tank' inline pump usually incorporates the pressure switch but works the same way.

Why any converter still uses micro switches taps is a mystery.

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[TheBig1]

plumb this in close to the pump and connect it and the pump to the 12v supply. just disconnect and ignore the microswitch wiring. as above it will allow the pump to run until it builds up pressure in the pipes. adjust this shutoff pressure using the knurled nut on the top

a very simple fix and easy basic diy

 

[Manic]

You could always fit a waterproof switch near the tap and reroute tap wire to that and use that to turn water on or off

 

[ianp]

Having a system pressure switch is quite a standard set up on small marine craft etc and is usually accompanied with an accumulator in order to smooth out any pulsations etc. They also, depending on the accumulator size, give some degree of pump free water supply as the accumulator is a reservoir. I'm not sure of the capacity of the small submerged pumps to be able to supply at the pressures required though without undue stress. Has anyone looked into it in depth rather than just as a quick easy way out?

 

[TheBig1]

Having a system pressure switch is quite a standard set up on small marine craft etc and is usually accompanied with an accumulator in order to smooth out any pulsations etc. They also, depending on the accumulator size, give some degree of pump free water supply as the accumulator is a reservoir. I'm not sure of the capacity of the small submerged pumps to be able to supply at the pressures required though without undue stress. Has anyone looked into it in depth rather than just as a quick easy way out?

once the pump has loaded the pressure past the non return valve, there is no stress on the pump. most caravan systems now work with a pressure switch and submersible pump