Shut off valve / switch for a Whale shower?

[Robinhood]

....I think Roger needs to have the mental strength to use only the cold tap, then turn it off and see how long the pump keeps running. :-)

 

If it turns off after some seconds, my theory is a variation of Keith's - a faulty non-return valve in the hot-water circuit.

 

The pressure up the "hot" side is often somewhat less than up the "cold" side, due to the convoluted route it takes.

 

Without a full-functioning non-return valve, with both taps (it being effectively a "mixer") open and the shower-head closed, the water could be pumped in a complete circuit until pressure equalises in both legs and the pressure switch is triggered (especially if there has been some drain-back in the hot side in the iterim).

 

With the cold-tap only open, without the non-return effect there is a possibility that there will be some back-flow created out of the "hot" side, which will only be re-pressurised when the cold-tap is closed (There would then be a pump run-on which would eventually cease as the hot-side reaches pressure).

 

 

[Derek Uzzell]

I envisage the water system in Roger’s Sundance comprising

 

1: A submersible water-pump (quite likely Whale-made) in the motorhome’s freshwater tank, with a hose leading to

 

2: a Whale in-line pressure-switch with a hose leading from this to a ‘junction’ where

 

3: one hose leads to the motorhome’s cold-water outlets and

 

4: another hose leads to a water-boiler (quite likely a Carver Cascade) where water is heated and

 

5: is led by hoses to the motorhome’s hot-water outlets.

 

Basically the type of simple system in the Fig 2 diagram here

 

http://www.whalepumps.com/rv/siteFiles/resources/docs/resource-library/db_180.25_v2_0211.pdf

 

but with the addition of a hot-water heater.

 

Although it’s usual for a system employing a submersible water-pump to have a non-return valve (NRV) on, or close to, the water-pump, evidently the Whale in-line pressure-switch has its own integrated NRV.

 

Assuming that Roger’s Sundance has a switch on its electrical control panel to turn the water-pump on or off, it should be straightforward to check the likelihood of the NRV being faulty.

 

Make sure the freshwater tank has plenty of water in it; turn the water-pump on; open all the water outlets and wait until water runs freely from all outlets without any ‘spluttering’; turn off all the water outlets at the taps.

 

The water-pump should now run until the pressure in the system has risen to a point where the Whale in-line pressure-switch turns off the electrical supply to the water-pump. Wait until this happens and then turn off the water-pump using the control-panel switch. Wait, say, 10 minutes. If the NRV is faulty, it should be anticipated that the pressure in the system will by now have dropped significantly as water drains back through the NRV into the freshwater tank. Turn the pump’s control-panel switch on and, if the water-pump does not begin to run, or only runs momentarily, then the NRV is OK. If the pump needs to run for a significant length of time, then the NRV is probably faulty.

 

This, however, is largely academic as far as Roger’s odd shower-head behaviour is concerned.

 

Let’s take my leak hypothesis first. This is predicated on there being a leak between the Whale shower unit’s cold tap and the shower-head. The leak has no effect on the pressure in the water system while the shower-head is ‘open’, but prevents the system being pressurised quickly when the cold tap is open and the shower-head is closed.

 

I’m going to suggest that, however peculiar it may seem that this only applies to the cold tap/shower-head combination, if water were emerging into the bathroom when the pump was failing to shut off, or (as the bathroom’s plastic fitting might prevent this occurring) if the floor beneath the bathroom (when inspected by looking under the motorhome) showed evidence of water seepage/damage, there’d be little doubt what’s happening.

 

As I said earlier, without knowing exactly how the taps are connected to the shower-head it’s difficult to know what’s going on, but it would certainly be advisable for Roger to check the floor’s underside. (And, if he tries out Robinhood’s suggestion to turn the cold tap on and the shower-head off and let the pump run until it stops (or doesn’t stop!) I’d definitely get someone to check whether water starts to drip from under the floor.)

 

When Roger’s Sundance’s water system has all its water taps shut off, the system is ‘closed’. The water-pump raises the pressure within the system until a predetermined pressure threshold is reached when the Whale in-line pressure-switch will turn off the pump’s 12V power-supply. As long as the NRV is OK and the system has no leaks (and the water-heater is not turned on) the pressure within the system should remain unchanged for quite a while.

 

If a bathroom tap is turned on (and the shower-head is turned on) the water system becomes ‘open’ - water will emerge from the shower-head, the pressure within the system will drop, the Whale in-line pressure-switch will turn on the pump which will pressurise the system. As long as the tap is turned on the pump will continue to run.

 

When the bathroom tap is turned off the pump will run until the predetermined pressure threshold is again reached when the Whale in-line pressure-switch will turn off the pump’s 12V power-supply. Roger says that, as long as the shower-head is not closed, turning off each of the two bathroom taps results in the pump stopping in less than 5 seconds. If he leaves the hot tap open (with the cold tap closed), but turns off the shower-head, the pump also stops in less than 5 seconds. But if he does the opposite, leaving the cold tap open (with the hot tap closed), when he turns off the shower-head the pump continues to run for minutes not seconds.

 

When all the hot taps in the motorhome are turned off, and the kitchen cold tap is turned off, and the shower-head is turned off, the Sundance’s water system is ‘closed’. Even if the bathroom’s cold tap is in its ON position, the system is still ‘closed’ and, unless water is leaving the system somehow (which will reduce the pressure in the system and cause the water-pump to continue to operate) the system will remain ‘closed’.

 

In Roger’s case there’s a pump in the freshwater tank that’s ’trying’ to pressurise the system and a pressure-switch that’s not shutting off the pump. While the pump is running it won’t matter whether the NRV is faulty or not, provided that the pump can force water through the NRV. And (as far as I can see) any suggestion that a ‘circular’ flow of water could be provoked in a ‘closed’ pressurised system by turning off the shower-head has the flavour of a Perpetual Motion Machine.

[Robinhood]

Quiet evening in, Derek? ;-)

 

Derek Uzzell - 2016-08-10 8:23 AM

 

.....and (as far as I can see) any suggestion that a ‘circular’ flow of water could be provoked in a ‘closed’ pressurised system by turning off the shower-head has the flavour of a Perpetual Motion Machine.

 

 

....well, that would be true of course if it were being suggested that this were going to continue "perpetually", but the suggestion was it could happen until pressure were equalised round the system.

 

It's a long time since I read fluid mechanics, but there are many circumstances under which this could occur.

 

Domestic water installation rules dictate, for instance, that a mixer tap that allows mixing of water within the tap body (rather than having two separate outlets), must have backflow protection on both legs to prevent such a happening. (And I know that in many circumstances, in this case the expected effective head on the two supplies may be vastly different, but in others, it will be roughly the same).

 

The problem is that much of all this is conjecture without knowing the full geography and componentry of Roger's system.

[Derek Uzzell]

Robinhood - 2016-08-10 9:03 AM

 

...The problem is that much of all this is conjecture without knowing the full geography and componentry of Roger's system.

 

Yeah - that’s the killer.

[RogerThat]

Hi everyone,

 

Sorry it's taking me a day or two to reply, work is crazy busy at the moment!

 

Thanks once again for all your detailed replies, thoughts and suggestions.

 

Derek's five-point list above of the water system is spot on and as promised here are some pics of my water system - along with what I *think* each part is. I may very well be wrong on my part identifications so don't quote me on the accuracy of these :)

 

(click on each picture to view the hi-res version)

 

 

Water tank (hot and cold, confirmed re Carver Cascade water heater):

 

https://owncloud.dg2.org/s/IeBlQyZyZnabSsA/download

 

 

On the left with the tag still attached is the Whale pressure switch, not sure what the item on the right is, NRV perhaps?:

 

https://owncloud.dg2.org/s/XAAultE3GmOhg61/download

 

 

Various connectors, these are situated to the left-side of the pressure switch:

 

https://owncloud.dg2.org/s/hyi4tKw2EsPFwNj/download

 

 

Connectors viewed from slightly higher up (again, click any of these to enlarge):

 

https://owncloud.dg2.org/s/mHd68fQAvEyKQwX/download

 

 

The in-tank submerisble pump:

 

https://owncloud.dg2.org/s/UkWGqRfcfcGOqwI/download

 

 

And not really relevant, just shown for completeness, the water-level sensor:

 

https://owncloud.dg2.org/s/Hg3hcvhWnSZ7bWa/download

 

 

Hopefully those pics will shed some light on my plumbing :)

 

Robinhood said: "I think Roger needs to have the mental strength to use only the cold tap, then turn it off and see how long the pump keeps running"

 

Yes, I need to man up, it would probably help lol :) There's no water in the system at the moment but this is something I intend to do. While at the same time, as Derek suggested, keep a very close eye both inside and outside for water appearing from places it shouldn't be appearing from!

 

I too am wondering (as per Robinhood suggestion above) if by shutting off the cold water supply at the shower head, if the water is then being pumped from the cold water tank, in to the hot water tank, in reverse. Does the Carver tank have a NRV on the outlet side to prevent this? Could this have failed? However, at some point one would then assume that the hot tank being back-or-reverse-filled would eventually contain enough pressure to shut the pump off (as the water can't return fully to the cold tank due to there only being one outlet which is being pumped out in the opposite direction). Maybe the pump will eventually stop after a few minutes? I need to be brave and test this out!

 

As suggested, I do have a switch on the main control panel of my MH to turn the water pump on and off:

 

https://owncloud.dg2.org/s/ZI8xNzLoOzNfgiY/download

 

I turn this off each night (I probably don't need to?) and when I turn it on the following morning, the pump doesn't make a sound - which suggests there is no pressure drop in the system when it's left for a several hours.

 

What I've not done is peer at the bathroom floor underneath the MH. If ever it stops raining here today I'll take a peek underneath and look for any signs of water damage or stains.

 

Which means, the things I need to do are:

 

1) Check under the bathroom floor outside for signs of a leak / water damage

 

2) Fill the water system, run the cold tap, turn off the shower head knob and wait...

 

3) While waiting (and counting/timing) to see if the pump does eventually shut off I'll also check for signs of leaks or drips both inside and outside

 

Anything else I can or should be checking while I have water in the system?

 

 

[Keithl]

Hi Roger,

 

The unidentified object next to your pressure switch is a 'grit;' filter.

 

It splits in 2 with a bayonet action to clean. It is recommended to clean it at least once a year.

 

Keith.

[Derek Uzzell]

Roger

 

As Keith advises, the object to the right of the pressure-switch is a filter. It’s almost certainly an old-style SHURflo filter - though I’ve never seen one installed ‘stand alone’ before. If you do decide to dismantle it to clean it, be careful as (given its age) it may be fragile. This link suggests that this design of filter is no longer available

 

http://www.marcleleisure.co.uk/store/filter-shurflo-posiflow-trailking-pump-threaded-cons-p-3808.html?osCsid=3e31a835e53567337cb9ec943973da89

 

so a breakage would require fitting the current SHURflo filter (example here)

 

http://www.marcleleisure.co.uk/store/filterstrainer-pumps-threaded-connections-p-3846.html?osCsid=3e31a835e53567337cb9ec943973da89

 

or dispensing with a filter altogether.

 

Whale’s exploded-view diagram for the in-line pressure-switch indicates that the switch’s non-return valve (NRV) will be in the switch’s body where the short length of hose joins the filter to the pressure-switch. There might be another NRV ‘upstream' of the filter (ie. between the filter and the freshwater tank) but this shouldn’t really be necessary.

[Robinhood]

...The Carver Cascade has an NRV integrated into the cold-water inlet, and these are known to fail from time-to-time.

 

I can't find reference to the pressure-switch having an integrated NRV, but as Derek refers to a cut-away drawing, I'll take his word for it.

 

I can't see any more NRVs in the system.

 

I doubt there is any NRV provision in the tap unit (and thus it could pump-over).

 

If you do your cold-tap test and the pump finally stops after some time, (negating the "leak" theory) my money is still on a faulty NRV at the Cascade inlet (though this is far from conclusive). (It could be a faulty NRV in the pressure switch, but this seems less likely as you don't appear to experience pressure loss when not in use).

 

It should be possible to check for this by heating the water, running the cold-tap test, and seeing if the (cold) inlet hose to the Cascade warms up (as would be potentially possible arising from reverse flow by overpumping through the unconstrained tap body).

[Derek Uzzell]

The “cut-away drawing” can be seen in this Whale document

 

http://www.whalepumps.com/rv/siteFiles/resources/docs/resource-library/db_180.25_v2_0211.pdf

 

Within the document’s “Handy Hints” section is the statement

 

b) If the pump cycles on/off:

- Supply voltage may be high because battery charger is on. Adjust switch (see leaflet 180.10) and/or fit a surge damper

- Check for air or water leaks in taps and piping

- Non-return valve may be held open by grit. Remove the two assembly screws in the inlet nipple to gain access to the non-return valve

 

[roger20]

A couple of years on and reading through this thread I wonder if the experts could give me some guidance please on using a shower in our new Hymer Exsis T.

In our Autotrail we had a shower head with an inbuilt cut-off switch which worked really well with the pressure sensing switch plumbing system - adjust temperature and minimum flow first, then cut-off the flow ready to shower. The Hymer sounds to have micro switches built into the taps so when using the cut-off on the shower head the pump is still running.

The Whale pressure sensing switch seems to be a possible solution. If I understand how this might work, turning the tap on will set the pump running and then the showerhead switch will cut the flow, thereby increasing the pressure in the pipework and so cutting the pump off a second or so later. Releasing the showerhead switch will reverse the process, the reduced pressure restoring power to the circuit again.

For those that may know the Hymer access hatch to the water pump/tank it looks like a fairly simple fix with easy access to break into the pipe from the pump for the Whale switch  and also into the  2 wires providing power to the Reich submersible pump.

The Autotrail had a system with a Shurflo pump which although not submersible still presumably relied on the water drawn from the tank (in the same way as a submersible) to create a system which was sufficiently sealed to enable the pressure valve to operate.

Does this look like a possible solution or could there be possible problems?  

[Derek Uzzell]

The Whale pressure-switch allows a submersible water-pump to be used while sidestepping the need to install the electrical wiring normally required for water outlets (taps, shower) that employ micro-switch operation.

 

Plainly, if you chose to insert the Whale switch into your brand-new Exsis t588’s water system, there will be a potential negative impact on the Hymer warranty, but in principle it should be practicable to hack into the Hymer’s wiring as you suggest.

 

My Hobby motorhome had a SHURflo pump triggered by tap/shower micro-switches, but it also retained its pressure-sensitivity. There are certain technical advantages to that arrangement, but the micro-switch wiring increased complexity.

 

In-line pressure-switches are not a Whale monopoly (example of Comet product here)

 

https://www.leisureshopdirect.com/water/caravan-plumbing/water-supply-fittings/pressure-switches/pressure-switch-comet

 

but I’m not aware of anyone having done what you are proposing.

 

(It OUGHT to work - but whether it would work well is another matter. I believe you’ll just have to suck it and see...)

 

 

[roger20]

Thanks Derek

Reassuring that your system had both but might just give Whale a call as well. Not concerned about hacking the wiring - already too far down that road anyway fitting a reversing camera and altering the radio wiring. As delivered the radio only plays when the engine is running. Serves us right for being penny pinching and not choosing the £2500 multi-media option!

[monique.hubrechtsgm]

Is the Whale name in above comments a brand or what ever it means? Apart from a real Whale.

[Derek Uzzell]

Whale is a brand, with its factories in Northern Ireland.

 

http://www.whalepumps.com/about.aspx

 

(Although their products have been used for many years by UK motorhome manufacturers, I doubt that they are used by non-UK converters.)

 

[aandncaravan]

roger20 - 2018-05-09 9:16 AMThanks Derek

Reassuring that your system had both but might just give Whale a call as well. Not concerned about hacking the wiring - already too far down that road anyway fitting a reversing camera and altering the radio wiring. As delivered the radio only plays when the engine is running. Serves us right for being penny pinching and not choosing the £2500 multi-media option!

Roger, I did exactly what you are proposing on my last van. The microswitches failed in 3 taps within a few weeks, so rather than replace the M.switches I took the opportunity to fit more modern taps that didn't have microswitch operation.Suggest you ensure that you have some kind of Pump isolation switch. The pump sometimes operates randomly through the night as pressure drops in the pipework so a good idea to isolate it when not being used.The vehicle might already have one, usually in the Earth return, but you might need to be careful how you wire things to keep that operational?I also fitted an inline pump at the same time to supplement the existing pump. However, that proved to be a waste of time, not improving the Shower flow at all.

[roger20]

Thanks everyone. I will go ahead and fit in due course and report back. On the Hymer there is already a pump switch in the bathroom which will isolate the circuit so the Whale pressure switch will just be an interruption of the circuit already in place. As the pump is in the tank rather than directly within the habitation area it does tend to be fairly quiet so I just need to take care not to let it run dry or without priming properly. Don't recall having these hearing issues 15 years ago!! 

[roger20]

Just an update to confirm that adding the pressure switch worked exactly as intended. It may need some fine adjustment because it seems sensitive to the battery voltage when initially adjusted.

Hopefully this may help someone else who likes to shower and use as little water as possible when the need arises.