What’s this?

[Banus]

So although everything is working perfectly, I imagine that the water system / filters haven’t been cleaned prior to me purchasing the van so thought I’d take a look.
I removed and checked the wire filter strainer on the side of the pump which was fine but then came across this which apart from being in line didn’t really have any clues as to what it was. Could it be another filter? Any idea?

 

[Jcloughie]

It is a surge damper. It stops the initial force from the tap.

Also, the filters do not get cleaned. They are either removed or replaced. But the tap strainers can be cleaned periodically.

John

 

[Gralay]

No it's not another filter it's a surge damper

 

[Gralay]

It is a surge damper. It stops the initial force from the tap.

Also, the filters do not get cleaned. They are either removed or replaced. But the tap strainers can be cleaned periodically.

John

Sorry John you beat me to reply
Gra

 

[audiorob]

(x3) Think you will find this is a surge damper for your water system.

If you have a filter it may be within the water inlet housing or in line depending on the system you have. Google 'caravan water filter' to see if you have either!
Always worth checking the screw filters at the end of tap spouts for debris - a regular task - but make a note of how it fits together as you remove it!

 

[ProfJohnL]

It is a surge damper. It stops the initial force from the tap.

....

Yes it is a surge damper, but its function is not quite what you have described.

The problem it solves is to prevent mixer taps and particularly showers from alternately pulsing with very hot water and the selected temperature when the cold pump is controlled by a pressure switch and whilst delivering water it is able to to generate enough excess pressure to cause its control switch to operate.

What happens is when the water system pressurises enough the cold pump is turned off and the cold water stops flowing instantly. However the hot water tank always has a small air cap which has been pressurised and continues to deliver the hot water even though the cold has stopped.

The hot water back pressurises the cold system through the taps mixing valve and prevents the the pump from turning on whilst the air cap continues to expand and push hot water out and drops its pressure, this eventually allows the pump to turn on again and restores the cold flow until it exceeds the pressure switches threshold.

The surge damper simply provides a similar air cap for the cold water side of the system, and this helps to match the pressure decay of the hot system and keeps both hot and cold systems in step with each other.

 

[Gagakev]

Yes it is a surge damper, but its function is not quite what you have described.

The problem it solves is to prevent mixer taps and particularly showers from alternately pulsing with very hot water and the selected temperature when the cold pump is controlled by a pressure switch and whilst delivering water it is able to to generate enough excess pressure to cause its control switch to operate.

What happens is when the water system pressurises enough the cold pump is turned off and the cold water stops flowing instantly. However the hot water tank always has a small air cap which has been pressurised and continues to deliver the hot water even though the cold has stopped.

The hot water back pressurises the cold system through the taps mixing valve and prevents the the pump from turning on whilst the air cap continues to expand and push hot water out and drops its pressure, this eventually allows the pump to turn on again and restores the cold flow until it exceeds the pressure switches threshold.

The surge damper simply provides a similar air cap for the cold water side of the system, and this helps to match the pressure decay of the hot system and keeps both hot and cold systems in step with each other.

Interesting Prof, so as you describe mine is not working correctly as the shower does pulsate, can the surger be cleaned? Or is a replacement on the cards?
PS: it has always pulsated so we are used to it now!!!

 

[Buckman]

Interesting Prof, so as you describe mine is not working correctly as the shower does pulsate, can the surger be cleaned? Or is a replacement on the cards?
PS: it has always pulsated so we are used to it now!!!

If not set up correctly it will pulsate and if you have one of those Eco camel shower heads even worse. Do you have the Whale system or Truma?

 

[ProfJohnL]

Interesting Prof, so as you describe mine is not working correctly as the shower does pulsate, can the surger be cleaned? Or is a replacement on the cards?
PS: it has always pulsated so we are used to it now!!!

Functionally it's just an upturned pop bottle to provide an air spring, and it should only contain air until the water is pressurised.

I personally have never come across one that lost all its air, but some may be lost as turbulent water entering at the bottom when it pressurises might absorb some of the air and carry it out into the pipe work when the pressure is released.

If yours has lost its air or its connection has become blocked then it can't function as intended.

Basically it shouldn't need cleaning, but there would be no harm if you did.

 

[Jcloughie]

Interesting Prof, so as you describe mine is not working correctly as the shower does pulsate, can the surger be cleaned? Or is a replacement on the cards?
PS: it has always pulsated so we are used to it now!!!

Pulsating may also be due to a badly set up pressure switch, if your system has one.

John

 

[ProfJohnL]

Pulsating may also be due to a badly set up pressure switch, if your system has one.

John

A surge damper is only necessary where a pressure switch is used. If the pump is controlled by switched taps, it runs as long as the taps are open, and there will be no differential pressure between hot and cold so mixing taps should work fine.

 

[Jcloughie]

A surge damper is only necessary where a pressure switch is used. If the pump is controlled by switched taps, it runs as long as the taps are open, and there will be no differential pressure between hot and cold so mixing taps should work fine.

I agree, but there are a few types of pressure switch, (which is why I said, depending on the installed system). If not adjusted properly and operating incorrectly it might be thought of as pulsating. I never suggested switched taps.
John

 

[Gagakev]

If not set up correctly it will pulsate and if you have one of those Eco camel shower heads even worse. Do you have the Whale system or Truma?

No Eco camel shower head, and on the Whale system.

 

[Gagakev]

Pulsating may also be due to a badly set up pressure switch, if your system has one.

John

All other taps work fine and yes do have pressure switch

 

[ProfJohnL]

All other taps work fine and yes do have pressure switch

Especially showers often have enough restriction to the flow of water that the pump can still cause the pressure switch to operate. so that is not overly surprising.

I should have made it clear the surge damper is designed to keep the pressure in both hot and cold more closely matched, which in turn prevents you getting surges of hot water which can scald in a shower.

 

[Banus]

Well that’s all very interesting and I’m glad that I didn’t try to prize it apart thinking there may be a serviceable filter in there. Talking of which, many of you must recognise this that I drop into my Aquaroll. Is it a filter, is there a filter in there, and can it be dismantled to clean any debris?

 

[otherclive]

Well that’s all very interesting and I’m glad that I didn’t try to prize it apart thinking there may be a serviceable filter in there. Talking of which, many of you must recognise this that I drop into my Aquaroll. Is it a filter, is there a filter in there, and can it be dismantled to clean any debris?

It’s more a strainer designed to stop bits/grit going into the pump and system.

 

[Ferrodo]

It’s designed to float to above the water level thus stopping any water flowing to your taps. Clever way of not flooding your van.

 

[Buckman]

It’s designed to float to above the water level thus stopping any water flowing to your taps. Clever way of not flooding your van.

How would that work as it is independent from the pump?

 

[otherclive]

How would that work as it is independent from the pump?

A TIC post perhaps?

 

[Banus]

Ok so I understand and can clearly see it’s a strainer / filter but was wondering if it’s possible to dismantle it to clear out the debris. All filters are either cleanable or replaceable. There is a groove visible at the base that I was tempted to slip a screwdriver into to prise apart but thought better of it without checking first!!

 

[Ferrodo]

How would that work as it is independent from the pump?

Ah Buckman my friend….twas nought but a joke

 

[otherclive]

If it’s doing its job only smaller stuff will get through and I’d have thought the system filter( if fitted) would then remove them, and isn’t that one replaceable? Looking on the web I cannot see any strainers sold individually all that seems around are replacement hose kits at circa £20+. Unless anyone can confirm that the strainer disassembles I’d tend to use a tap or garden hose to flush in the normal flow direction.