water pump surging

[iotum]

My motorhome (Adria Compact SL Plus) has had water pulsing issues from new. I have a Whale pressure switch and an in tank Reich High Power Pump plus water pump.

 

After many attempts to find the perfect setting for the Whale pressure switch I decided to fit a Whale surge damper which fixed the problem immediately. All was well until I filled the water system the other day and now the surging is back but at a slower pulsing rate. I've tried adjusting the whale pressure switch setting over it's full range and all I can get is either pump on or pump surging. At no point can I get the pump to shut down.

 

Consequently I am now having to switch the pump off and on at the main control panel to avoid constant noise from the pump and wearing out the pump / switch.

 

My immediate thought was that I must have a leak somewhere caused by a frozen pipe over the winter. But I took particular care to drain the system of water using a Floe draindown attachment and also driving the vehicle around with the drain valves open for a while to release any dregs of fluid.

 

I've scoured around the vehicle looking for any sign of water leaks but nothing is showing up.

 

Also when I run the pump there's no air coming out of the taps (at least not yet) which I would have expected with any sort of leak in the pipes.

 

So my current conclusion as likely cause is :

1 - An air leak at a pipe joint that is letting in air and I haven't found the water leak yet.

2 - A faulty pressure switch

3 - A faulty pump

 

Does anyone have any other suggestions of likely cause or steps I could follow to diagnose the problem more accurately.

 

Thanks

 

Tim

[rajohno]

Tim, are you sure the surge damper is still working.

The whale damper uses an air cushion within a plastic honeycomb to cancel the pulses in the system, it may have lost its air or the honeycombe may be compromised putting you back to square one, not the best designed damper considering the price!

[iotum]

As far as I can tell it's ok. It's just an upside down bottle of air so I didn't think there was much to go wrong with it. If it had a leak then I would expect to hear air coming out of it followed by water.

 

Have thought of one thing to try which is to drain the system and pressurise it with the Floe adapter and see if it maintains the 15 psi .

[Derek Uzzell]

Welcome to the Out&AboutLive forums, Tim.

 

I’m quite surprised that Adria would have fitted to a 2017 motorhome a water system that includes an ‘old tech’ Whale pressure switch.

 

Whale’s literature for their pressure switch is here

 

http://www.rainbow-conversions.co.uk/user/downloads/Whale/Adjusting%20your%20pressure%20switch.pdf

 

but the advice doesn’t really address the problem you’ve described.

 

Obviously the Reich pump is in working order because it is delivering water to the taps. As I understand it, the water emerging from the taps shows no sign of spurting/spluttering that might suggest air is entering the water system. (In fact, with a submersible-pump like the Reich pump, the only way for air to get in when the pump was running would be at the pump’s inlet inside the fresh-water tank.)

 

Suggest you drain down completely, make absolutely sure all drain-valves are fully closed, carefully refill and see if that does any good. If there are no water leaks and the problem is still present, logically the switch must be the prime suspect.

[witzend]

iotum - 2021-04-27 6:49 PM

 

My motorhome (Adria Compact SL Plus) has had water pulsing issues from new. I have a Whale pressure switch and an in tank Reich High Power Pump plus water pump.

 

Tim

If the Reich pump has a pressure relief valve could it be that your Whale switch is conflicting with it

[iotum]

Thanks for the welcome Derek. This forum contains so much useful info for the newbie like me. Even if it doesn't provide the answer it contains explanations which get me thinking about ways to solve problems.

 

I'm away in the van right now - first outing after lockdown - but will do more investigating when I get back. I've also ordered replacement pump and pressure switch. Even if not required then good to have spares.

 

Yes I was surprised at the Whale pressure switch. It seems very fussy and off grid can require frequent changes. Adria have put the switch under the steps to the bed area which is normally only accessible from the garage and not easily if you have a lot of stuff in there. So I've modified the steps so I can now lift off one of the stairs (magnetically attached) and access the switch so it's much quicker to adjust.

 

On the surging issue I have a new theory. I'm assuming the Reich pump has a non-return valve upstream of the impeller. If that is damaged or stuck open then it would explain the surging and also why I'm not getting air in the system (because the pump is under water, it also has some sort of auto vent feature so any air in the pump should automatically bleed out).

 

I'll take a more detailed look when I get home and maybe swap it out with the new pump. If that resolves the problem then I'll see if it's possible to disassemble it and fix it and it can become my spare pump.

 

Will update this post when I know more.

 

thanks all for help so far.

[Derek Uzzell]

Reich submersible water pumps come in various models that have different flow rates and water delivery pressures. The 1st image attached below shows a current “Power Jet Plus” pump with a 25 litres per minute flow rate and a delivery pressure of 2.1 bar.

 

Some Reich pumps have an integrated check valve (non-return valve - NRV) but most don’t. A NRV is needed to prevent water siphoning back through the pump into the fresh-water tank, and the NRV may be attached to the pump’s outlet (arrowed in the 1st image), or close to the outlet but separate. An example of a Reich NRV is shown in the 2nd image.

 

Historically, some submersible water pumps were notoriously reluctant to prime and, when initially submerged, needed to be shaken to expel air and allow the pump’s impeller to 'get a grip’ on the water. OK if an Aquaroll-type external water container was being used, but not if the pump was in a motorhome’s fresh-water tank. Reich advertise “a patented ventilation system which is integrated into many of our pumps and provides immediate output after immersing into the tank”, and your Reisch pump should have that feature ad not suffer from priming problems.

 

As you are considering swapping your original water pump for a new one, presumably you can get at the original pump fairly easily. It would be worth you checking that there’s no ‘crud’ in the impeller area and giving that part of the pump a good clean. But I wouldn’t bother swapping the pump over until all else fails, as the symptoms suggest the cause of the surging is elsewhere. (As far as I’m aware - as the pump needs to be waterproof - it would not be practicable to dismantle/repair your original pump.)

 

If there’s no water leakage preventing the water system from pressurising properly, the prime suspect for the ‘surging’ must be the Whale Pressure Switch. So if the problem does not spontaneously cure itself, beginning by swapping the Pressure Switch would make sense. And, if there are no leaks and fitting a replacement Pressure Switch and pump is ineffective, that would just leave the Whale surge damper. Installation instructions for the damper are here

 

https://www.camperlands.co.uk/downloads/whale-surgedamper-instructions.pdf

 

The Whale damper is quite ‘cheap and cheerful’ (though not exactly cheap) with no pressure adjustment. As mentioned in this 2013 Caravantallk thread

 

https://www.caravantalk.co.uk/community/topic/78809-busted-whale-surge-damper/

 

the Whale damper can faill, but (as you mentioned in your 2nd posting above) if the damper’s body cracks, it should be expected that water would leak from it.

 

Problems are not always explicable. While on holiday in France in 2018 the pipework of my Rapido’s water system suddenly began to vibrate violently, sufficiently so that we cut the trip short and came home to the UK. I thought the SHURflo water pump was at fault (as that seemed the obvious reason) but replacing the pump made no difference. Once the water pump had been judged blameless and I’d investigated further, because I couldn’t access much of the Rapido’s water system pipework, I sidestepped the problem by rejigging the pipework so that the part of the system in which I believed the problem lay was no longer in use. Fortunately this ploy cured the vibration, but I’ve no idea what the root cause of the vibration was, how a motorhome specialist would have addressed the problem or how long they would have taken.

[iotum]

Thanks Derek. You were correct, it was the pressure switch.

 

I took it apart this afternoon and found a loose rubber valve as you can see in the attached photo. Popped it back into the obviously correct location, reassembled and all is good again.

 

I was wondering what might have caused the valve to come loose in the first place. I suspected the use of the floe air clearing system so I tested that and then took the pressure switch apart again but the valve was still in the correct spot. But I did notice that there was still water in the tube behind the valve. So my guess is that the water froze and pushed the valve out. One to remember for next winter.

 

So quite a useful experience as I now know a bit more about how my van works and I also have a spare pump and pressure switch which I can keep handy for any future emergencies.

 

Thanks all for the input and hope this might prove useful for anyone else who gets surging with a whale pressure switch.

[Derek Uzzell]

This webpage carries an exploded view of the Whale Pressure Switch

 

https://www.whalepumps.com/marine/siteFiles/resources/docs/product-accessories-spares/Fresh_inline_pressure_switch.pdf

 

and the item that became loose in your valve is identified as a “Non return valve”.

 

This Whale document

 

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

 

and the “Helpful Hints” section includes the following advice:

 

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.

 

(I notiice that there’s a Whale video showing how to clean the switch’s NRV.)

 

 

So the Pressure Switch’s NRV not sealing properly (which would certainly have been happening in your case!) plainly can cause pump-cycling to occur. (I assume there’s another NRV on or near your Reich pump.)

 

You may well be right that residual water freezing inside the Pressure Switch pushed the NRV out, or your ‘Floe-ing’ when you winterised your motorhome displaced the NRV but not when you carried out the test yesterday. Either way it’s something to be aware of and will be very helpful for other motorcaravanners that have a motorhome with the dreaded Whale switch.

[iotum]

Thanks Derek. Have saved a copy of that exploded view for future reference. Suspect this might not be the last issue I have with the pressure switch.

 

The Reich pump has no NRV attached. I think it just relies on a vacuum to prevent the water syphoning back into the tank when the pump is turned off. It seems to work but we do notice that the pump occasionally comes on without a tap being opened. It won't be a perfect seal so air will eventually break into the vacuum. Alternatively if the pump has been turned off at the main control panel then when switching back on there is a brief operation of the pump as it brings everything back up to pressure...same reason.

 

I suspect the reason Adria have left the NRV off is to reduce the risk of damaging the pump with ice in the the winter. Without the NRV, once the rest of the system has been drained then any water between the pump and the outlet of the tank would drain out into the tank. With an NRV then it would just sit there unless forced out by operating the pump to clear it. The Adria manual does state that you should run the pump to clear it when draining down but it's an easy one to forget with potentially expensive and annoying consequences.

[Derek Uzzell]

Truana’s advice about submersible and ‘pressure’ water pumps can be found here:

 

https://www.truma.com/uk/en/camping-guides/guide-water-pumps-for-motor-homes-and-caravans#to-502f261c-696d-4dea-8200-77d5300c745f

 

and this other link may be useful

 

https://www.outandaboutlive.co.uk/caravans/articles/practical-advice/caravan-water-systems

 

The usual arrangement for modernish motorhomes is that, when a submersible water pump is fitted, the pump is turned on and off via micro-switches on the taps and shower water-outlets. This, of course, adds complication, with pairs of electrical cables leading from each outlet and - if no NRV were fitted - water would siphon through the the pump back into the fresh-water tank and the system would lose pressure. Then, when an outlet was opened, there’d be a significant delay before the system came back up to pressure and a good stream of pressurised water was delivered from the outlet.

 

However, as Adria has chosen to fit the pesky Whale Pressure Switch that has its own NRV, there should be no imperative need for another NRV at or near the pump.

 

Even when there’s a NRV attached to a subersible pump’s outlet, that NRV will be ‘downstream' of the pump itself and, when the water system is drained down, the fresh-water tank is empty and thereand there might be residual water trapped ‘downstream’ of the NRV, the submersible pump should still self-drain.

 

I admire your faith in Adria’s risk management philosophy. As they’ve chosen for a motorhome a ‘caravan type’ cheap as chips water system, it’s just as likely the omission of a NRV is due to penny pinching.