Adjusting pressure in a Fiamma A20 expansion tank

[Iansolo231]

Hi there



The water flow in my tap has started pulsating when I open it halfway. The pipe that feeds it comes from the water tank to a pump, to a Fiamma A20 expansion tank and to the tap. I have read several places that this is probably a pressure issue in the expansion tank, so I wanted to be sure that the pressure there is correct. But I read on the Fiamma website that the tank comes precharged at 0.9 bars, so is it at a lower pressure than atmospheric or am I missing something? It also says that you can adjust the pressure with a compressor, but if you want to be lower than atmospheric pressure you’d need something creating vacuum, not a compressor, or?

If anyone has ever check the pressure on the expansion tank themselves I’d be very happy to know how you did it.

Cheers,

Ian

 

[donkey]

Hi

Not sure why you would think .9bar was a negative pressure. It is equal to 13psi.

Geoff

 

[poppycamper]

Hi there



The water flow in my tap has started pulsating when I open it halfway. The pipe that feeds it comes from the water tank to a pump, to a Fiamma A20 expansion tank and to the tap. I have read several places that this is probably a pressure issue in the expansion tank, so I wanted to be sure that the pressure there is correct. But I read on the Fiamma website that the tank comes precharged at 0.9 bars, so is it at a lower pressure than atmospheric or am I missing something? It also says that you can adjust the pressure with a compressor, but if you want to be lower than atmospheric pressure you’d need something creating vacuum, not a compressor, or?

If anyone has ever check the pressure on the expansion tank themselves I’d be very happy to know how you did it.

Cheers,

Ian

13 psi ( 0.9Bar) is what the A20 comes preset at... you can however increase/decrease to suit your pump pressure.
As above not sure where you get vacuum from... ??

 

[poppycamper]

If anyone has ever check the pressure on the expansion tank themselves I’d be very happy to know how you did it.

Tyre pressure gauge.!!

 

[pwilmo]

There is a valve and cap on top of the A20, be careful adjusting the pressure as 13psi in the small A20 space is very easily lost.
Usually if you've lost pressure( pulsing water) the diaphram or diaphram seal has had it.

You can buy replacement diaphram and fit yourself, take off the A20 so you can work on it. It's dead easy to undo bolts, N.B.make sure you take note/pictures of the position and placement of the existing diaphram to ensure successful repair.
Then pump up with bycicle pump, not air pump(too fierce) to 13psi

The A20 levels out the water pressure by seperating the water flow and an air chamber with a rubber diaphram, on one side is the water, on the other side is a sealed air chamber.

If water pressure goes low then the 13psi pushes the diaphram outward into the water flow and increases the water pressure. If the water pressure goes high then the water is able to press the diaphram inwards, thereby reducing the water pressure.

Hope this helps

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[Iansolo231]

Hi all, thanks a lot for your help.

I think my confusion comes from the fact that when they say that the preset pressure is 13 psi, that means 13 psi above atmospheric pressure, so we're always using atmospheric pressure as the reference, or put in another way: atmospheric pressure = 0 psi (correct me if I'm wrong).

I took my bike pump (which indeed indicates 0 psi when not connected to anything), pumped it up to 20 psi (because my pump delivers 30 psi) and things seem to work much better now. I'll wait a few days see if the pressure holds.

Cheers,
Ian

 

[Richard n Ann]

Hi all, thanks a lot for your help.

I think my confusion comes from the fact that when they say that the preset pressure is 13 psi, that means 13 psi above atmospheric pressure, so we're always using atmospheric pressure as the reference, or put in another way: atmospheric pressure = 0 psi (correct me if I'm wrong).

I took my bike pump (which indeed indicates 0 psi when not connected to anything), pumped it up to 20 psi (because my pump delivers 30 psi) and things seem to work much better now. I'll wait a few days see if the pressure holds.

Cheers,
Ian

Sometimes referred to as PSIG (gauge)
The other is PSI (absolute)

The g is usually dropped off though

 

[Richard n Ann]

I took my bike pump (which indeed indicates 0 psi when not connected to anything), pumped it up to 20 psi (because my pump delivers 30 psi) and things seem to work much better now. I'll wait a few days see if the pressure holds.

My new Seaflo expansion tank came with 10psi (gauge) in it. Just thought I'd try it first and it works very well, the pump stays off for about 3 seconds with the tap open half way the pump is a 30psi Shureflo

 

[pappajohn]

Atmospheric pressure is a variable .
At sea level it's 14.7psi.
At 20000ft it's only 6.4psi.