Problems with Hymer water system (1 Viewer)

Jul 5, 2013
11,713
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Tunbridge Wells, Tunbridge Wells, UK
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On our latest outing the microswitch on my Hymer basin tap failed for the second time and a few days later so did the one on the kitchen tap. I am getting fed up with this especially as they are very awkward to fix. At the moment I have rigged a simple on off switch using the basin's wiring. So I just switch it on and the pump starts to run and then just open the tap you want to use. The problem is that if you forget to switch it off the pump will probably burn out, so this can only be a temporary fix.

It seems to me that I have three options.

Option 1. Just keep replacing them each time they break. The problem with that is that it will be time consuming for me to do or expensive to employ somebody to do it for me.

Option 2. Do what Lenny HB did and replace the Hymer's submersible pump with with a pressure switched Sureflow pump I have discussed this with him, but my problem is that the noise of that pump running to flush the toilet in the middle of the night would wake up y wife. And also my double floor is only 125mm or so high so it would be very difficult to fit anywhere convenient.

Option 3. Replace the micro switched method of turning on and off the pump with a pressure switch system. This would have the advantage of keeping the quiet submersible pump and also would seem to me to be simpler to do, so . Has anybody done this on a Hymer and if so how did they make it work please. I am not sure how I could make this work with the toilet and also what I do with the existing microswitch wiring. The internal and external shower still work on the microswitch so should I disconnect them too?

Has anybody successfully carried out Option 3, and if so can they explain how please?

Many thanks for any help you can give
 
Jul 2, 2019
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doncaster
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Im with lenny on the spray bottle ,or even a fairy liquid bottle and a good circular squirt 👍
 
Apr 27, 2008
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Eastbourne East Sussex
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Although I haven't tried it, what I would try would be to fit a pressure switch anywhere in the cold supply, wired to the original connections from the duff tap. It won't matter if you turn on a tap with a working microswitch that the pump is effectively turned on both by the pressure switch and the microswitch. If another microswitch fails you won't even know.
 

Two on Tour

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Sep 16, 2016
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Although I haven't tried it, what I would try would be to fit a pressure switch anywhere in the cold supply, wired to the original connections from the duff tap. It won't matter if you turn on a tap with a working microswitch that the pump is effectively turned on both by the pressure switch and the microswitch. If another microswitch fails you won't even know.

One of these should fit the bill.

https://www.rainbow-conversions.co.uk/water-fittings/whale-in-line-pressure-switch-674-p.html

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Nov 4, 2011
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I fitted a Whale pressure switch instead of micro switches.
I just cut the main pipe from pump and fitted the switch in that line, removed one wire from from pump feed and used twin core wire to extend this wire to the switch and return to pump.
removed the wires from one of the tap micro switches and joined wires together, set whale switch sensitivity, job done.
since then I have changed back to the micro switch system, but I can’t remember why, maybe the other half didn’t like the clicking from the pump occasionally.
 

OldAgeTravellers

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Jan 6, 2014
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Wake pressure switches tend to be rather iffy. Manic tried one and got rid of it and OldAgeTravellers tridd one as well and ended up fitting a Shureflo type pump.
In fact I am now back with the Whale switch and it is working well.
I got fed up with failing micro switches at ridiculous prices so fitted a Whale switch in the rear by the trauma heater. I then took all the micro switches out of circuit. Then realised that if the frost dump ever worked the pump would run for ever so fitted a micro switch to that, to cut the pump if the dump valve opened I also fitted a relay to the D+ switch so as to cut the pump when the engine was running. Then when in Portugal the Hymer pump failed and I couldn't find a replacement so I temporarily fitted a bulge pump from a chandlers and bought a SeaFlo pump, the nautical version of the SureFlow pump to fit when I got home. That worked very well with "at home" type pressure but the pressure switch kept burning out so I went back to the whale pressure switch which was still in circuit at the rear of the motorhome so not so affected by the pumping pressure. I have recently fitted an accumulator to further smooth out flow as the pump is so powerful. It has been an expensive journey but I am pleased with the final result. Yes the pump is noisier than the centrifugal one but most of that is transmitted vibration through the chassis.

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peterc10
Jul 5, 2013
11,713
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Tunbridge Wells, Tunbridge Wells, UK
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Thanks for all the comments. We prefer to spray with diluted washing machine liquid and flush with water. Wife hates the smell of stale pee.

As I understand it the microswitch system does not turn on the pump directly such that the current runs through the switch itself. Looking at the gauge of wire it would probably not take the current. Instead the wires goes to a relay which then switches on the current to the pump. Is that correct? If so, I am struggling with the concept of running pump wires directly to the taps. Surely they need to go to the relay or relays (not sure if each tap has its own relay or all the taps share one relay). I am no electrician and would not recognise a relay and do not know where it, or them, are in my Hymer. And I am also struggling to understand how the toilet flush manages to switch on the pump, as I do not want to stop that working.

So could someone help me with more information on how Option 3 works please, as that is the one I still favour if I can have it. We had a Sureflow pump in our previous motorhome and hated the noise it made when it turned on, whether we were trying to sleep or not.
 

Lenny HB

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Oct 18, 2007
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Fairly certain there isn't a relay. The switch wires connect to larger wires in the loom, the small cables to the only account for 500mm of the total length of several meters.
 
Last edited:
Feb 22, 2008
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We use top tank liquid diluted in spray bottle, smells sweet , not as sweet as me, and reduces water and cassette emptying .

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peterc10
Jul 5, 2013
11,713
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Tunbridge Wells, Tunbridge Wells, UK
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Fairly certain there isn't a relay. The switch wires connect to larger wires in the loom, the small cables to the only account for 500mm of the total length of severalmeters.
So that means the small wires take the full current? That might explain why the switch I installed felt warm in use! And it could explain why the microswitches fail so often?
We use top tank liquid diluted in spray bottle, smells sweet , not as sweet as me, and reduces water and cassette emptying .
As I understand it that kills the enzymes in the bio laundry detergent we put in the cassette.
 
Nov 4, 2011
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When I did mine as I said link one of the micro switch wires together ( van side not tap side) this in affect makes the pump run constantly and then one pump wire to one side of whale switch and the other whale wire to the pump.
 

OldAgeTravellers

LIFE MEMBER
Jan 6, 2014
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Thanks for all the comments. We prefer to spray with diluted washing machine liquid and flush with water. Wife hates the smell of stale pee.

As I understand it the microswitch system does not turn on the pump directly such that the current runs through the switch itself. Looking at the gauge of wire it would probably not take the current. Instead the wires goes to a relay which then switches on the current to the pump. Is that correct? If so, I am struggling with the concept of running pump wires directly to the taps. Surely they need to go to the relay or relays (not sure if each tap has its own relay or all the taps share one relay). I am no electrician and would not recognise a relay and do not know where it, or them, are in my Hymer. And I am also struggling to understand how the toilet flush manages to switch on the pump, as I do not want to stop that working.

So could someone help me with more information on how Option 3 works please, as that is the one I still favour if I can have it. We had a Sureflow pump in our previous motorhome and hated the noise it made when it turned on, whether we were trying to sleep or not.
On ours there was no relay but the switches fail because of the very tight bend in the thin wire as it enters the microswitch.
Your option 3 was my initial attempt. All I did was to fit the whale pressure switch as I said, in my case at the back next to the Trauma Heater. Then I shorted out all the tap switches taking them out of service so I could just have the Whale microswitch in the circuit. The Hymer pump will then run until the selected pressure is reached and you now have a pressurised system. The toilet flush works fine on a pressurised system. I didn't even bother to isolate the switch wire on it although we rarely use the flush as it uses too much water. We use a spray bottle all the time.

Things to note:
  1. Best to carry a spare pump, mine failed within a few months but it may have been on the way out anyway.
  2. Fit an isolating switch so as to be able to turn the pump off when not using the van or if you get a leak.
  3. Be aware that the system is pressurised so it is best to check that all joints are sound.
  4. If you don't fit a micro switch on the dump valve, even more important to switch the pump off when not using the van.
  5. I fitted a relay to reduce the current on the switches, could be another point of failure if not.
  6. Check that the one way valve above the pump is good or the pump will keep switching on for no apparent reason.
  7. if you don't understand relays then also switch the pump off when motoring so there is no risk of leaks from pipes flexing in transit.
Good luck.

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Sep 10, 2019
3,358
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Warwickshire
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Hymer camp c546
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Use a spray bottle at night.
We too use the spray bottle at night, also colour changing light, motion detected, ( not that kind) :X3: which you can set to a certain colour, under the toilet rim, so no need to disturb each other or grandkids, popping the light on, hope you get sorted
 

Lenny HB

LIFE MEMBER
Oct 18, 2007
52,710
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On the coast in West Sussex
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658
MH
Hymer B678 DL
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Since 2008 & many years tugging
So that means the small wires take the full current? That might explain why the switch I installed felt warm in use! And it could explain why the microswitches fail so often
Had 3 Hymer always used the microswitches until I fitted the Shureflo pump on this one.
It ever been the microswitch itself that has failed always the wires or connections to them.

Its the poor design of the tap that causes the problems.

I think the switches are rated at either 6 or 10 amps pump takes less than 4amps.
 

Lenny HB

LIFE MEMBER
Oct 18, 2007
52,710
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On the coast in West Sussex
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658
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Hymer B678 DL
Exp
Since 2008 & many years tugging
also colour changing light, motion detected, ( not that kind) :X3: which you can set to a certain colour, under the toilet rim, so no need to disturb each other.
We could switch on the low level night time curtesy lights but don't need to because of those stupid blue LED's that are permanently on in the cab reading lights. :LOL:

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peterc10
Jul 5, 2013
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Tunbridge Wells, Tunbridge Wells, UK
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On ours there was no relay but the switches fail because of the very tight bend in the thin wire as it enters the microswitch.
Your option 3 was my initial attempt. All I did was to fit the whale pressure switch as I said, in my case at the back next to the Trauma Heater. Then I shorted out all the tap switches taking them out of service so I could just have the Whale microswitch in the circuit. The Hymer pump will then run until the selected pressure is reached and you now have a pressurised system. The toilet flush works fine on a pressurised system. I didn't even bother to isolate the switch wire on it although we rarely use the flush as it uses too much water. We use a spray bottle all the time.

Things to note:
  1. Best to carry a spare pump, mine failed within a few months but it may have been on the way out anyway.
  2. Fit an isolating switch so as to be able to turn the pump off when not using the van or if you get a leak.
  3. Be aware that the system is pressurised so it is best to check that all joints are sound.
  4. If you don't fit a micro switch on the dump valve, even more important to switch the pump off when not using the van.
  5. I fitted a relay to reduce the current on the switches, could be another point of failure if not.
  6. Check that the one way valve above the pump is good or the pump will keep switching on for no apparent reason.
  7. if you don't understand relays then also switch the pump off when motoring so there is no risk of leaks from pipes flexing in transit.
Good luck.
Many thanks for that. Not sure what you mean by "shorting". Is that just connecting the two incoming wires together? Is it essential to do all of them. Will one or two be enough to supply permanent current to the whale switch? I ask because I do not know how to get to the showers.

As to your things to note
1 Yes we have always had a replacement Reich pump, complete with non return valve and hose. Never been used yet
2 Hymer already has an isolating switch for the water pump. Do I need another?
3 Will do that.
4 Our Alde system does not have an automatic dump valve. We have a manual one. If we are not using it in winter I always drain the system by hand, If we are using it in winter the heating is usually always on.
5 Would not know how to do that. What switches are you referring to? The only one will be in the pressure switch wouldn't it?
6 What valve are you referring to? The non return valve above the submersible pump seems to work well. We have never experienced any spluttering on our system. The only other one would be in the whale unit. Do they fail like that often?
7 Our system seems to be watertight. The taps run water for a while when switched on without the pump on.

Finally, do you know if there are better alternatives to the Whale unit? I understand that they are fiddly to set up because they are sensitive to different voltages on the system when charging. Seems to be strange that they do not fit a voltage stabiliser.


We too use the spray bottle at night, also colour changing light, motion detected, ( not that kind) :X3: which you can set to a certain colour, under the toilet rim, so no need to disturb each other or grandkids, popping the light on, hope you get sorted
When you get to our age you go so often that you can get there with your eyes shut :ROFLMAO:
 
Last edited:
Nov 4, 2011
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You only need to to one switch wires, gives pump permanent supply for the whale switch to control.
 
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peterc10
Jul 5, 2013
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Tunbridge Wells, Tunbridge Wells, UK
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I am a bit confused when reading Whale's information about the pressure switch. They say that it is suitable to fit to a 1/2" flexible pipe in one part of their specification and a 10mm flexible pipe in another part. Will this fit the flexible pipes in my Hymer system or will I have to get an adaptor?

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Lenny HB

LIFE MEMBER
Oct 18, 2007
52,710
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On the coast in West Sussex
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658
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Hymer B678 DL
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Since 2008 & many years tugging
I am a bit confused when reading Whale's information about the pressure switch. They say that it is suitable to fit to a 1/2" flexible pipe in one part of their specification and a 10mm flexible pipe in another part. Will this fit the flexible pipes in my Hymer system or will I have to get an adaptor?
Looks like the only version now is is for ½“/12mm quick fit fittings
Hymer pipes are 10mm so you will need quick fitting into semiridged pipe then adaptor to 10mm.

Make sure you buy nylon adaptors as the polyprolene ones break when you try to fit them to speedfit pipe.
I found if you warm speedfit pipe up, then with a bit of force you can get it on to a 12mm adaptor.
 
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peterc10
Jul 5, 2013
11,713
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Tunbridge Wells, Tunbridge Wells, UK
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A class
Exp
Since 2013
Looks like the only version now is is for ½“/12mm quick fit fittings
Hymer pipes are 10mm so you will need quick fitting into semiridged pipe then adaptor to 10mm.

Make sure you buy nylon adaptors as the polyprolene ones break when you try to fit them to speedfit pipe.
I found if you warm speedfit pipe up, then with a bit of force you can get it on to a 12mm adaptor.
According to their catalogue on their website their pressure switch can be used with 10mm flexible pipes, presumably with a jubilee clip, as well as their own 12mm system of pipes and fittings which they call Quick Connect. No mention of Speedfit.
 

Coolcats

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Uggh - I could just about live with not flushing but going to the loo at night without washing your hands no way :sick:
I’m with you on this always flush and hand wash anything else……well……🤮🥴

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Jun 12, 2020
449
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I know you have a liking for option 3, but in my van I can switch off the pressure-switched pump overnight and there is still enough pressure in the system for a silent, quick flush and hand wash.
 

Lenny HB

LIFE MEMBER
Oct 18, 2007
52,710
147,676
On the coast in West Sussex
Funster No
658
MH
Hymer B678 DL
Exp
Since 2008 & many years tugging
According to their catalogue on their website their pressure switch can be used with 10mm flexible pipes, presumably with a jubilee clip, as well as their own 12mm system of pipes and fittings which they call Quick Connect. No mention of Speedfit.
I miss read it.
I clicked on specification it said no specification for this product a good website not.

Does say fits their own 12mm Quick Connect & ½" flexible so it looks like a short length of ½" pipe & adaptor.

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