# Jerky water pump



## wp1234 (Sep 29, 2009)

A question to any new Rapido owners - is your water pump jerky ?

Ours seems to operate in a pulse type fashion especially when having a hot shower .Ive checked the obvious things like a blocked filter, and loose water pipe connections but nothing seen that might cause this 

Is this normal on Rapido models if not any thoughts on where I should look next ?

Thanks
Wyn


----------



## Poulbot (Nov 8, 2013)

The reason for the pulsing is generally due to the pump trying to push a certain volume of water through an opening which is not large enough to allow it and therefore causing back pressure which the pressure switch is sensing (assuming it's a pressure pump, Shurflo etc).
A very simple demonstration of this is if you slowly close the tap, as you restrict the flow the pump will start to pulse. So I assume you have the tap fully open when demanding water?
Does it happen on all taps? Hot and cold? How old is the M/H?


----------



## wp1234 (Sep 29, 2009)

It's a 3 month old Rapido 9 and it seems to happen with hot and cold no matter what position the shower control is in.
Thanks to your message I've carried out a few tests and it seems the fault lies with the shower head itself so, taking off the head and running the water cures the issue . 
The new Rapido showers seem to have some sort of water saving head ( the make of it is Ecocamel) so I guess this has an internal fault .


----------



## shingi (Apr 18, 2008)

Fit yourself a Whale Surge Damper 720 available from many motorhome accessory outlets, which you place next to the pump between that and your main outlet feed. Not unique to Rapidos, affects all types. Cheers Mick
(Costs about £20 and comes with fitting instructions.)


----------



## Poulbot (Nov 8, 2013)

It might be worth asking your Rapido dealer if he has come across any other M/H's with the same issue. I am surprised that Rapido have released a M/H with a known problem as I think they are a pretty good brand.
You have a number of options, which you may or may not want to carry out if the M/H is still under warranty.
You could fit an accumulator tank after the pump in order to absorb these fluctuations in pressure.
You could fit a shower head which allows more flow.
You could increase the setting of the pressure pump switch to make it less sensitive to the back pressure.
The downside of the last option is that you would put your plumbing system under greater pressure on standby.
You also need to check the maximum working pressure of the water heater because you don't want the pump to exceed that figure.


----------



## wp1234 (Sep 29, 2009)

Mick thanks for this . 

More tests and it seems that it mainly the hot water that causes the pulsing , I take it this surge damper works on hot as well as cold ?


----------



## Poulbot (Nov 8, 2013)

Surge dampers / Accumulator tanks / expansion tanks are fitted just after the pump (pressure side) on the cold water line.
In this way all outlets, either hot or cold will have a smoother flow.


----------



## wp1234 (Sep 29, 2009)

Interesting , never heard of them before . I wonder why manufacturers don't fit as standard . Do most Motorhomes fit them then or does it just depend on how ' jerky' the system is ?
Cheers
Wyn


----------



## Poulbot (Nov 8, 2013)

They don't fit them because it is an extra cost, generally on the larger systems the plumbing system doesn't suffer from the same sensitivity as the smaller ones and also I think many of the smaller systems use the submersible type of pump which doesn't have a pressure switch but have microswitch taps.


----------



## eurajohn (May 9, 2005)

It's not a problem unique to Rapido or indeed the type of shower head fitted but as advised earlier one of the pump and plumbing. 
Normally it will not cause problems or poor shower performance and an accumulator will certainly stop it.

If you search back you will find TECHNO100 documented with pictures the fitting of one to his Rapido.


.


----------



## shingi (Apr 18, 2008)

Hi again Wyn,

Just supporting what the others have said, this surge damper will definitely solve your problem. Before ordering/buying it, check the diameter of the exit pipe from your pump (normally 15mm) as the only other bit you'll need is "T" connector to introduce it into your existing system, and the damper itself must be installed vertically perhaps against an adjacent partition.


----------



## deefordog (Dec 31, 2013)

If fitting a Shurflo accumulator http://legacy.shurflo.com/pages/Food_Service/beverage/accumulator_tanks/tanks.html, it's important to set the charge pressure with the pump OFF and at least one outlet open. This is detailed in the operation manual in the above link. The link covers the installation aspects and the accumulator can be mounted in any position.

If the existing pump has a pressure/flow switch on the base (as per a Shurflo Trail King), this needs to be set so that at low flow rates (<4lt/min?), there's at least a 2 second gap between the pump turning on and turning off. This is covered in the Trail King manual but I can't find the link at the moment - sorry.


----------



## wp1234 (Sep 29, 2009)

Thanks for all the great info.
As my Motorhome is still under Rapido warranty I've emailed them to see what they have to say .
As pointed out I can't be the only one with this problem can I .

Will report on the response when I get it.

Wyn


----------



## TheNomad (Aug 12, 2013)

If your present pump is a Fiamma one, then consider swopping it (or getting dealer to swop it!) with their electronic sensor control version. It's a straight swop as the fittings and mounting bolt holes are in the same places.
This was only option for us as I had no room near pump to fit and expansion tank.

I changed ours for one of them a few months ago, and the difference really is massive.....no more surging or pumping at the taps or shower head at all. VERY happy indeed.

http://www.amazon.co.uk/Fiamma-Aqua-Sensor-Water-Pump/dp/B004N6XUQI


----------



## Pudsey_Bear (Sep 25, 2008)

Link to Techno100 (Andy) pump accumulator thread

http://forums.motorhomefacts.com/63...apido-7090-project-thread-66.html#post1151212


----------



## wp1234 (Sep 29, 2009)

TheNomad said:


> If your present pump is a Fiamma one, then consider swopping it (or getting dealer to swop it!) with their electronic sensor control version. It's a straight swop as the fittings and mounting bolt holes are in the same places.
> This was only option for us as I had no room near pump to fit and expansion tank.
> 
> I changed ours for one of them a few months ago, and the difference really is massive.....no more surging or pumping at the taps or shower head at all. VERY happy indeed.
> ...


t's a Shurflo Trial King 2095-204-112 that's fitted to my Rapido so now I'm wondering if there is an electronic adjustment that can be made to improve the surging effect.Also space for an anti surge gizmo under the floor if I need to fit will be challenging - more research needed.

Is there a new series 9 owner out there experiencing the same issue ?


----------



## deefordog (Dec 31, 2013)

wp1234 said:


> t's a Shurflo Trial King 2095-204-112 that's fitted to my Rapido so now I'm wondering if there is an electronic adjustment that can be made to improve the surging effect.Also space for an anti surge gizmo under the floor if I need to fit will be challenging - more research needed.
> 
> Is there a new series 9 owner out there experiencing the same issue ?


Same pump that we've just fitted to our 2008 Kontiki except that ours is the 10lt/min version. I'd be tempted to tweak the pressure switch on the base to see what happens. If you note where it's set to start with, you can always return to this point if adjustment makes no difference to your problem.


----------



## Pudsey_Bear (Sep 25, 2008)

As mentioned previously check the pressure the water heater can stand be for upping the pump


----------



## deefordog (Dec 31, 2013)

IIRC, the 7lt/min Trail King 2095-204-112 will deliver a max 20psi with an open outlet. The flow switch merely cuts the pump in and out as the system pressure drops when a tap is opened. Just found this on the Shurflo website, not specific to the OP's pump but gives some extra info:

*PRESSURE SWITCH OPERATION (If Equipped) The pressure switch reacts to outlet pressure, and interrupts power at the preset shut-off pressure indicated on the pump label. When outlet pressure drops below a predetermined limit (*typically 15-20 psi. [1-1.4 bar] less than the shut-off pressure), the switch will close and the pump operates until the shut-off (high) pressure is achieved. The shut-off pressure is set to factory calibrated standards. CAUTION: Improper adjustment of the pressure switch setting, may cause severe overload or premature failure. Refer to SHURflo Service Bulletin #1031 for the adjustment procedure. Failures due to improper adjustment of the pressure switch setting will not be covered under the limited warranty. If the plumbing is restrictive or the flow rate is very low, the pump may re-pressurize the outlet faster than the fluid is being released, causing rapid cycling ( *ON/OFF within 2 sec.). If the pump is subjected to rapid cycling during normal operation, or for infrequent periods, damage may occur. Applications which exhibit rapid cycling should have restrictions in the outlet minimized. If not feasible consider a SHURflo Accumulator or a SHURflo "bypass" model pump.*


----------

