Pressure switch clicking !!!

[Kenzo]

Hi All,
We recently purchased a new Adria caravan. We have an issue... When we run the taps, all is well and the pressure switch kicks in just after the tap is closed. But it makes a "clicking" sound that is very annoying. I have followed the manual instructions in trying to reset it and although I have been able to reduce the "clicking" to 4-5 clicks, it is still there. The system seems to be working fine besides.
Is there a knack or trick in fixing this that I am missing. The dealer representative told me that the advice from Adria was "that the clicking is the sound of the switch doing its job i.e. it’s the pressure building up in the system to the point where the power to the pump is cut off"... Correct ???
I appreciate your help.
Many thanks,
KK

 

[Damian]

A pressure switch does exactly what its name suggests, it operates on pressure of the water to activate the microswitch.
It is not unusual for it to operate a few times on initially switching a tap off, but it should not keep operating continuously.
It is more pronounced when using hot water as it takes time to rebuild the pressure in the hot system.

 

[ProfJohnL]

Hello KK

The dealer is correct, it is the pressure switch doing what its supposed to do.

You do not tell us which Adria model of van you have or the type or make of pump that's fitted, but I believe its most likely a Truma submersible pump. This means you have a separate pressure switch fitted inside the caravan.

You wont do any damage if you try adjusting the pressure switch a little above or below the manufactures recommended settings, this might cure the problem, but do ensure the pump does actually turn off and not just sits there spinning without moving any water - that will shorten the pumps working life quite dramatically.

The only other way to remove the problem is both expensive and frankly I would not recommended it but: you could replace the pump control system by replacing all the taps with ones that contain a micro switch. The micro switches are all wired in parallel, so when ever a tap is opened its micro switch turns on the power to the pump. The down side to this approach is there's a lot more wiring and I'm not convinced the micro-switches are the most reliable devices.

 

[Kenzo]

Thank you all for replying.
The model is Adria Adora Rhine with a whale pressure switch.
I am pleased that all seems well and I may have another go at doing a slight adjustment to see if it "lessens" the clicking.
Prof, I don't see us replacing the taps and as you say the current system may be better and more reliable. Thanks for the advice. I appreciate it.

Best,
KK

 

[Gafferbill]

Hi Kenzo..............your Whale water pump is displaying symptoms of a high battery voltage which causes it to pulsate.
Do you always have your on board battery charger turned on?
If so your caravan's 12 volt supply will be in excess of 13 volts and your Whale pump works best at 12 volts.
Turning off the charger may solve the problem.

If your Whale pump is the submersible type then Whale has a modification that cures the pump of its susceptibility to battery voltage.

Whale IC pump control

........I have just updated my submersible pump with a new pump and controller and I can vouch that the system works well completely curing any pulsating.

 

[ProfJohnL]

Hello Gaffer,

I have seen this assumption of pressure switch oscillation due to high battery voltage before but I cannot see any logical explanation for it.

Can you explain what you think is happening?

 

[Gafferbill]

Yes Prof........the problem is known as hunting in a control system.

The control system in this case is the pressure switch which is manually set to register pressure in the system in order to turn the pump off when the taps are closed and on when they are opened.
This setting will be different for any given battery voltage since it is battery voltage that determines the pressure the pump can achieve.
If the pressure switch is set when a low voltage is available and then a high voltage is applied the switch will over correct itself detecting low pressure as soon as the pump stops and switching the pump immediately back on again and then detecting high pressure and immediately switching back off again.....thus pulsating or hunting.
Eventually this pulsating builds the pressure to a point where the pump switches off completely and stops pulsating.

Readjusting the pressure switch to the high voltage available to stop this pulsating will cause the pump to fail to turn off when a lower voltage is available.

For their pressure switch submersible pumps Whale highlight the problem in this video

........note that the OP has only told us that he has a Whale pressure switch so I am assuming he has a Whale pump which may not be the case.

 

[ProfJohnL]

Hello Gaffer,

Thank you for your answer,

I had to read it several times to understand what you believed is occurring.

Yes Prof........the problem is known as hunting in a control system.

I'm not convinced the effect we read about is technically hunting in its strictest sense, and i will explain why a bit further down.

The control system in this case is the pressure switch which is manually set to register pressure in the system in order to turn the pump off when the taps are closed and on when they are opened.

This setting will be different for any given battery voltage since it is battery voltage that determines the pressure the pump can achieve.

I agree with these two bits 100%

If the pressure switch is set when a low voltage is available and then a high voltage is applied the switch will over correct itself detecting low pressure as soon as the pump stops and switching the pump immediately back on again and then detecting high pressure and immediately switching back off again.....thus pulsating or hunting.

Now this is the bit that does not ring true:- We established the pressure switch is manually set to a particular threshold level. The switch setting does not change during this pulsing effect so it cannot "over correct" as that implies there is a feedback signal to modify its setting, and that does not exist in this system. So this means some other effect is causing the actual pressure to oscillate, and that oscillation is being detected by the pressure switch.

Eventually this pulsating builds the pressure to a point where the pump switches off completely and stops pulsating.

Readjusting the pressure switch to the high voltage available to stop this pulsating will cause the pump to fail to turn off when a lower voltage is available.

I agree with that.

So what is the cause of the oscillating water pressure, and having thought a bit more about it its better described as water hammer, where a mass of water is moving in a pipe and its inertia causes a pressure differential at either end of the pipe. The pipe has some compliance, and so the slug of water has some freedom to move like a piston in a cylinder.

In a caravan water system there is quite a lot of complaint material, the pipes are a relatively soft plastic with walls that have elastic characteristics, and where there is a storage water heater there is a necessary volume of air to allow for expansion of water as it heats. All the characteristics needed for the hammer effect.

Having worked on a design of a Submersible impeller pump, I can tell you the research we did looked at a wide range of makes and models pumps. All the pumps had different detailed characteristics which explains why Whale state the Watermaster system may not work with all pumps. But there is a general pattern of flow vs pressure when at low back pressures you get maximum flow, and you get maximum pressure with zero flow or "stopped off". The graph of flow vs pressure is an convex curve rather than a straight line. This is important because depending on where you set the pressure switch on the curve will affect the systems tendency to oscillate or not.

Its important to understand that the pressure switch will have some hysteresis. It will switch over when ever the pressure oscillation is greater than hysteresis value of the switch.

With a low pressure switch setting, the pump will be capable of passing a higher flow of water which will have a greater inertia. So if the pump stops, the water will try to continue causing a momentary low pressure. this may be detected by the pressure switch causing the pump to turn on again for a moment. this may repeat a few times until enough water has been locked in the pipe by the Non return valve damping the oscillation to a point smaller than the switch's hysteresis.

By setting the pressure switch to the upper flatter portion of the pumps pressure curve, the higher back pressure prevents such a large flow of water which means the inertial energy is much lower so the hammer effect is contained withing the natural hysteresis of the pressure switches characteristics.

This also explains the effect of the change if the supply voltage is increased. The pumps transfer curve is raised higher which puts the pressure switches setting into the high volume portion of the curve.

So the effect is "hammer" rather than "hunting"

 

[Gafferbill]

Hello Gaffer,

I have seen this assumption of pressure switch oscillation due to high battery voltage before but I cannot see any logical explanation for it.

Can you explain what you think is happening?

..........So you did know what was causing the pump to pulsate!

I did not think I was making an assumption........ I thought I was offering some advice to the OP to help him with his problem.
I did not assume I was the fountain of all knowledge so I backed up my post with a link to Whale who obviously can speak with more authority on the subject than I can.

hammer.......hunting.......pulsating...... all offer a good description as far as I can see

 

[ProfJohnL]

..........So you did know what was causing the pump to pulsate!

To quote a line from a music hall song "No I didn't know that i knew!" :cheer: It just needed a nudge on this occasion to get the little grey cells working . Life University- Fluid Mechanics 101 :side:

 

[Kenzo]

Hello Gafferbill and Prof...
I am impressed with your depth of knowldge but I am a man of limited technical knowledge and dont know if the answer to my problem is contained in here.
The submersible is a truma and the pressure pump is a whale so I wonder if the Warermaster IC will work. I am also confused as to why I need one of these. This is a brand new caravan and surely the pressure swithch should not be pulsating / clicking. BTW, I dont think we have an onboard battery charger and if we have I don't know where it is or how to turn it off.... !!!
So, I still have a pusating pressure swithch and am a little concerned about that.

Thanks a mill,
KK

 

[Parksy]

Hello Gafferbill and Prof...
I am impressed with your depth of knowldge but I am a man of limited technical knowledge and dont know if the answer to my problem is contained in here. KK

Don't worry KK, we're no wiser either :huh:

The submersible is a truma and the pressure pump is a whale so I wonder if the Warermaster IC will work. I am also confused as to why I need one of these. This is a brand new caravan and surely the pressure swithch should not be pulsating / clicking. BTW, I dont think we have an onboard battery charger and if we have I don't know where it is or how to turn it off.... !!!
So, I still have a pulsating pressure switch and am a little concerned about that.
Thanks a mill,
KK

Most new caravans have onboard battery chargers but the pulsating could be caused by a number of factors, air in the system is a very common cause. When you connect the water ensure that you turn on both hot and cold taps at the furthest point from the pump, this will probably be the shower and washroom sink. When the water has stopped spluttering and runs freely turn off and do the same with the kitchen taps. The hot water boiler has to fill up and if it hasn't done so this might introduce air locks which would cause pulsing.

 

[Dustydog]

http://en.m.wikipedia.org/wiki/Hysteresis
For us mere mortal caravanners the above link will demonstrate you too can help solve the OPS problem.

 

[Gafferbill]

Kenzo.......I realize that I don't really know what I am talking about so you should take advice from your other contributors.

Please ignore any contribution I have made to your thread.

 

[Dustydog]

The submersible is a truma and the pressure pump is a whale so I wonder if the Warermaster IC will work.

Thanks a mill,
KK

Kenzo
Can you clarify the above statement please.
Is your pump submerged in the aquaroll or is it a free standing Whale like mine inside the caravan?

My on board Whale pump has a "hunting" water pressure surge " water hammer " damper fitted adjacent to the pump.
For six years now after a tap is closed the onboard pump c tines to run from 2 to 5 seconds before switching off. This is deliberate and normal.. Every few hours or so the pump may kick in for a fraction of a second to maintain pressure for when a tap is next turned on.

is this what you are experiencing?
It could be the damper is defective ??

Going forward may I suggest you send a copy of this entire thread to your dealer, Adria Truma and Whale requesting their technical answer to your problem ASAP.

Good luck

 

[colin-yorkshire]

Hello Gafferbill and Prof...
I am impressed with your depth of knowldge but I am a man of limited technical knowledge and dont know if the answer to my problem is contained in here.
The submersible is a truma and the pressure pump is a whale so I wonder if the Warermaster IC will work. I am also confused as to why I need one of these. This is a brand new caravan and surely the pressure swithch should not be pulsating / clicking. BTW, I dont think we have an onboard battery charger and if we have I don't know where it is or how to turn it off.... !!!
So, I still have a pusating pressure swithch and am a little concerned about that.

Thanks a mill,
KK

hi KK.
if I could be so BOLD and suggest you forget the exelent technical do-dahs bits , and all that!!.
and for a minute consentrate on the practical side of things. simply put, you have a pump in a container that is powered by the vans 12v electrics this fills the water system with water half of this goes to the taps, (cold) the other half goes to a tank with an element that heats it up, this in turn also goes to the taps (hot) in order to obtain water either hot or cold you turn on the tap the the water comes out, ok so far!!!, in order to keep the taps flowing the pump replenishes the system with fresh water out of the container, and that is all there is to it!!!!!!!.
however there is a complication, and that is without some sort of device to cut power to the pump it will continue to run endlessly, and in a short time the pump would fail.
there are two ways one can do this though either,
1. have micro switches in each tap, so when the taps turned on the pump starts and replenish the water and then cuts the power to the pump when the taps turned off, or.
2. instead of on the taps have a micro switch on a pressure device that controls the operation of the pump by sensing a drop in pressure when the taps turned on,
both types of control will work with the same objective and that is to reduce the time the pump actually runs and exetend it's life,
one problem exists however with the pressure sensed system, this is of course obvious!!! and that is the pump will continue to run even after the taps turned off, until the water pressure rises to a predetermined level and as a consequence will also turn the pump on if the pressure drops for other reasons.
also as the switch operates it emits an audiable click that can de distracting at times if it operates frequently, this can be reduced by manual adjustment (the method is described in the van handbook) but it is always going to do this!! it is a part of caravanning we all have to accept using water from a container,
personally I find it less distracting than the noise one gets on site from a day to day basis, if it does bother you at night turn off the pump at the switch, when water in not required. and back on in the morning.

EDIT,
BTW, if your water pump pulsates as you describe, it will probably be a poorly adjusted pressure valve, I doubt there will be anything faulty in such a new van, imho, the system is working correctly just not at the right time. mine goes out of adjustment just by draining the system,(end of stay) it is the first thing I do after setting up once everything is connected at the site.

 

[ProfJohnL]

HEllo Kenzo,

I'm sorry if the explanation of what happening lost you a bit. So lets try to be more proactive.

Most caravan pump systems will from time to time exhibit the effect you describe. This is not exceptional and does not represent a fault.

According to Adria's web site they only use Truma submersible pumps in their current ranges. That also means they will use the Truma pump connection which means you cannot fit the Whale Watermaster IC system - it simply wont fit the Truma components.

I have not been able to find any alternative control system, which rather limits your options.

Dusty's suggestion of a surge damper may work, but its not actually designed to prevent your specific problem.

I suggest the first and no cost option is to re-adjust the pressure switch to work at a slightly greater pressure. It won't harm the caravan system, but there is a danger if the battery voltage falls the pump may not turn off. You would need to be watchful about this and adjust the pressure switch down a bit as the voltage changes.

You might find another pump may not exhibit the same oscillation. Even pumps of the same model will have slight differences in performance which might be just enough to prevent your problem.

You could go further and fit the Whale pump and inlet fitting along with the IC component.

Ultimately it may be a case of accepting it.

 

[Kenzo]

Hi All,
I contacted Whale in this matter. While I have yet to adjust our pressure switch, I thought in may be helpful to post the relpy, kindly emailed to me by Whale. Thanks to them for taking the time to reply. I will post agin once I have adjusted the pressure swithch, which hopefully will fix our problem.

Thanks to all for taking the time to post

KK.

I have been forwarded your details to contact you regarding your enquiry related to water system pressure switch settings. The issue you have explained regarding the pressure switch clicking means that the product needs adjusted. When the switch leaves the production line it will be set to a default setting, this setting will be close to the switching position required for most caravan systems, but as every caravan model is slightly different some adjustment may be needed. With the difference in caravan models being more or less pipe work and number or style of outlets, adjustment may be required. Having to adjust the pressure switch is perfectly normal and if the caravan is used on battery, adjustment would have to be made depending on the performance of the battery. If the pressure switch is set too high then the pump will not turn off as the pressure required to activate the switch will not be achieved. If the switch is set to low the switch may click on and off repeatedly and cause fluctuations in flow of the water supplied.

Setting the switch can be a bit of a fiddle if you’re not used to it or familiar with it but becomes easier with practise. If you have the caravan connected to mains power and your aqua roll filled and connected you can then adjust the pressure switch. On the pressure switch there will be a small knob that can be turned, if it is turned clock wise the off pressure will be increased, anti-clock wise the off pressure is decreased.

• Ensure the water system is connected and main pump switch is on.
• Turn the knob clock wise until it starts to tighten but do not tighten it up as we will need to turn it back again.
• Open the kitchen outlet on cold and listen to make sure the pump starts to run, there should also be flow at the outlet.
• Now close the outlet, the pump should continue to run and not switch off.
• While the pump is running, slowly turn the knob on the pressure switch anti clock wise until the you hear a click and the pump stops running. You have now found the off pressure setting.
• Go the kitchen outlet and open it, when the pump starts to run close it again. The pump should now stop.
o If the pump does not stop the pressure adjustment knob will need another slight or quarter turn anti clock wise
o If the switch makes multiple clicks but the pump does stop then you can adjust it slightly higher “Clock wise”.

How close to the correct pressure setting you want depends on the individual but with a bit of time and slow carful adjustment a perfect setting can be achieved.

If you always caravan with mains hook up this should not need adjusted again but in some cases it may need a slight adjustment to allow for settlement or aging of the system. However if you caravan using the battery and no mains hook up then the pressure switch will need adjusted as the battery performance falls, the less voltage in the battery then more you will have to reduce or back off the pressure switch to allow the pump to achieve off pressure.

In the attached link in your email the IC unit was mentioned. This IC control can only be attached to a Whale water master socket and not an inline pressure switch or Truma socket. The IC unit when used with the water master socket will regulate the pressure setting for you on mains or battery meaning you do not have to adjust the pressure switch setting. It will also detect an empty aqua roll and stop your pump from running continually when dry. This will preserve the life of the pump and avoid premature failure.

I hope this information is of help but if not please contact us via telephone and we can talk you through the pressure switch setting process and or any other Whale product related questions.

 

[Dustydog]

Thanks Kenzo.

An excellent response from Whale which will be of great use to a lot of caravanners.
Maybe PCv could publish it in a future edition.

 

[Len_Cuff]

As I randomly suffer from this problem, can someone tell me what this pressure switch looks like? Assume it'll be in the front locker where the water comes in and the hot tanks is? (Adrea Adora 2010)

 

[ProfJohnL]

There is a picture here

http://www.seamarknunn.com/acatalog/whale-pressure-switch-5200.html?gclid=CjkKEQjwia-dBRC07eeatYGe-78BEiQArZhbgKUJHqpyTsLv290V5_yO3lLKpSqfZIqMhtx4Et1DlrLw_wcB#.U6vGTPldU2E

 

[Gafferbill]

The explanation from Whale clearly states that their pressure switch can only be accurately set for any given battery voltage.

The battery voltage changes when the battery charger/power supply is turned on and this will put the pressure switch out of adjustment.

The OP in his original post complained of repeated clicking of the pressure switch after tap turn off.........this in my experience (for a submersible pump system) is a symptom of a switch set to turn off at one battery voltage and then being subjected to a higher battery voltage such as when a supply from the charger/power supply is turned on and available to the pump.

I passed on this information to the OP in post 5 of this thread.

Many people only caravan with an electric mains hook up and with their charger/power supply turned on 24/7.
In this scenario, once your pressure switch has been set to this voltage, it is unlikely to display the symptoms described by the OP