# Fiamma Expansion Tank



## dovtrams (Aug 18, 2009)

Hi

This bit of kit was mentioned a few months ago, is it worth fitting it and what does it do?

Dave


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## twinky (Aug 11, 2008)

It acts as a kind of shock absorber for the water pressure. They are a pressure vessel containing an air filled balloon. When you shut off the tap a back pressure is created and these will absorb that, supposedly protecting the pump.

I was going to get one of these for my previous van that made a right racket when shutting the tap. Sold the van first though.

Are you looking at these because you have a problem?


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## JohnsCrossMotorHomes (Jul 21, 2007)

dovtrams said:


> Hi
> 
> This bit of kit was mentioned a few months ago, is it worth fitting it and what does it do?
> 
> Dave


Hi,

For £20 odd they are worth fitting as it absorbs the pump pulses and you get a steady stream of water instead of 'squirts' as the pump works.

It also will extend the life of the pump

Peter


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## Rudderman (May 31, 2005)

I got one from JohnsCrossMotorhomes a couple of years ago. Money well spent, I would not be without one.


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## gnscloz (Oct 4, 2008)

will this quieten the pump down and stop thr surging then? assume it fits before pump then?


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## JohnsCrossMotorHomes (Jul 21, 2007)

gnscloz said:


> will this quieten the pump down and stop thr surging then? assume it fits before pump then?


Hi,

No it fits after the pump!

Peter


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## Rudderman (May 31, 2005)

Hi

Yes, this will quieten the noise a bit, but it must be fitted AFTER the pump.


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## 1300man (Dec 30, 2008)

hi i see theres a valve fitted ,does it need air pressure.if it does what psi.


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## RichardnGill (Aug 31, 2006)

Some vans have these or similar fitted from new.


I am sure ours has one fitted as standard.

It might be worth checking before buying one.


Richard...


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## Rudderman (May 31, 2005)

Yes, you need to pump it up to the pressure that your pump runs at,
ie. A 16psi pump should have 16psi in the expansion tank, (I think, but check on this!) I use a bicycle pump.


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## 1300man (Dec 30, 2008)

thanks ,rudderman ill try and blow it up 8O


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## sallytrafic (Jan 17, 2006)

0.9 Bar is the pressure that they require. They can be put anywhere in the system downstream of the pump. The advantage of the accumulator is felt to be greater in a small water system as there is some give in pipework.. If your shower pipe is empty then that will do almost as well


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## JohnsCrossMotorHomes (Jul 21, 2007)

1300man said:


> thanks ,rudderman ill try and blow it up 8O


The expansion tank eliminates the pulsating operation of the pressureswitches and assists the flow of constant water at the required quantity.
It will assist in lowering the water consumption and will extend the life of both the pump and the water boiler *(pre charged at 0.9 bar - 13.05 PSI)*Weight;0.3kg.
Size;23.5cm x 15cm x 10 cm


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## zappy61 (May 1, 2005)

*fiamma expansion tank*

Just fitted the A20 expansion tank. I have a surflo RV pump but the instructions don't mention the model or the pressure. So not really sure what pressure to pump the tank up to. Also do you pump it up when it is pressurized by the pump or when it is not under any pressure?

Any suggestions would be appreciated.

Regards,

Graham


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## FoweyBoy (Dec 7, 2006)

Mine was already pressurised. I tried it as it was and it worked fine so left it! I can't remember what the pressure was or if the instructions told you what the preset pressure was.

I found the best benefit was the ability to get a small water flow from the tap without the pump keep cutting in. It helps save water.


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## zappy61 (May 1, 2005)

FoweyBoy said:


> Mine was already pressurised. I tried it as it was and it worked fine so left it! I can't remember what the pressure was or if the instructions told you what the preset pressure was.
> 
> I found the best benefit was the ability to get a small water flow from the tap without the pump keep cutting in. It helps save water.


Thanks for that, mine was pressurised to 0.9 bar but I think someone said that the pressure nees to be that of the pump output.

Graham


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## twinky (Aug 11, 2008)

zappy61 said:


> FoweyBoy said:
> 
> 
> > Mine was already pressurised. I tried it as it was and it worked fine so left it! I can't remember what the pressure was or if the instructions told you what the preset pressure was.
> ...


Graham

I think I'm right when I say that the function of these vessels is to absorb the back pressure when the tap is turned off.

The pressure of your pump therefore is not that important.

However if the pressure in the vessel is set too high it would be ineffective ie a dead end. 0.9bar should be fine.


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## zappy61 (May 1, 2005)

twinky said:


> zappy61 said:
> 
> 
> > FoweyBoy said:
> ...


Yes I think I will set it at about 1 bar or 14psi.

Thanks,

Graham


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## JohnsCrossMotorHomes (Jul 21, 2007)

The main reason for installing a pressure acumalalor is to smooth out the pump pulses at the tap so you get a steady stream of water.

The acumalator builds up a 'head'of water which under pressure comes out in a steady stream which also means that the pump is not constanty running and only kicks in when the pressure drops in the system

Peter


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