Pressure to start with in an accumulator tank

[Kendorr]

My pump is rated at 3.5 bar, I've just purchased a Seaflo 1L accumulator to put in the system and hopefully stop the pump pulsing.

 

The accumulator is currently pre charged to 10 psi, or 0.7 bar.

 

Question, is there any way of knowing approximately what pressure the accumulator should be pre charged to for the system as it will be much easier for me to add pressure whilst I'm at home?

 

Ta very glad - Kevin

[robbio c]

Hi Kevin it should be set to a few psi above  the pump cut in pressure.

[Kendorr]

1 hour ago, robbio c said:

Hi Kevin it should be set to a few psi above  the pump cut in pressure.

Right. I'd better find the instructions and figure out what the cut in pressure is!!

[TheBiscuits]

1 hour ago, Kendorr said:

it will be much easier for me to add pressure whilst I'm at home

 

It's usually a standard schrader valve, so any bike pump or foot pump with a pressure gauge is quite easy to do it with, even in strange corners or lockers.

 

If you can't get access to the valve in situ, the accumulator is installed in the wrong place so consider moving it ...

[BEngo]

You can find the cut in pressure with the accumulator installed.

Turn the pump on and the taps off.  Allow the pump to run till it switches off.  Measure the pressure in the accumulator.  This is the cut out pressure, for future reference.

Turn a tap on slowly and wait till the pump switches on. Immediately switch the pump off.    You may need to do this a couple of times to get the switch on point.

Measure the pressure in the accumulator. This is the cut in pressure.

 Open the tap till the water stops.  Pressurize  the accumulated to cut in pressure.

 

Turn on pump   close taps when the water flow is even.

N

 

[Tracy D'arth]

Pump up the accumulator to around the pump cut OUT pressure.

Switch it on and let it pump, taps closed,  till it stops. Slowly, very slowly  reduce the accumulator air pressure till the pump just cuts back in.

Its about right. Saves messing measuring pressures which usually lets air escape as you measure.

[PD1964]

1 hour ago, robbio c said:

Hi Kevin it should be set to a few psi above  the pump cut in pressure.

Watched a YouTube Vlogger reset his accumulator and he says you should set the pressure lower then the cut in pump psi not higher.

 Also Jabsco say set lower then the pump cut in?????

 

https://www.jabscoshop.com/files/Accumulator and Expansion Tank Instructions ZPWL4 doc595.pdf

Edited March 21, 2021 by PD1964

[Tony Brooks]

I find about half the pump cut out pressure works but if its just 1 litre you need all the volume for water you can get so Tracy's method would do that.

[robbio c]

Just now, PD1964 said:

Watched a YouTube Vlogger reset his accumulator and he says you should set the pressure lower then the cut in pump psi not higher.

 Also Jabsco say set lower then the pump cut in?????

 

https://www.jabscoshop.com/files/Accumulator and Expansion Tank Instructions ZPWL4 doc595.pdf

Ok thanks for that pd

[Kendorr]

Thanks folks, the accumulator is at home and not fixed in the system yet, so I'll make sure to have it where the valve is easy to access. It is a Schrader valve in the accumulator, but my bikes use a Presta valve, this is why I want to set it at home and use my cycle pump which has a gauge and I don't drive, so more difficult to change when on the boat.

2 hours ago, Tracy D'arth said:

Pump up the accumulator to around the pump cut OUT pressure.

Switch it on and let it pump, taps closed,  till it stops. Slowly, very slowly  reduce the accumulator air pressure till the pump just cuts back in.

Its about right. Saves messing measuring pressures which usually lets air escape as you measure.

Thanks Tracy, I'll set it to 40 psi and give this a go, easier for me to remove pressure on boat than to add it ?

[nicknorman]

3 hours ago, PD1964 said:

Watched a YouTube Vlogger reset his accumulator and he says you should set the pressure lower then the cut in pump psi not higher.

 Also Jabsco say set lower then the pump cut in?????

 

https://www.jabscoshop.com/files/Accumulator and Expansion Tank Instructions ZPWL4 doc595.pdf

Yes you want the accumulator to be nearly empty, but not empty,  when the pump cuts in, so a few psi below pump cut in pressure. It’s not that critical though.

 

[blackrose]

On 21/03/2021 at 14:42, robbio c said:

Hi Kevin it should be set to a few psi above  the pump cut in pressure.

 

I thought it was supposed to be set a few psi below the water pump cut in pressure?

 

As opposed to a hot water expansion tank fitted to the calorifier which should be set at the pump's cut out pressure or a few psi above.

On 21/03/2021 at 16:21, PD1964 said:

Watched a YouTube Vlogger reset his accumulator and he says you should set the pressure lower then the cut in pump psi not higher.

 Also Jabsco say set lower then the pump cut in?????

 

https://www.jabscoshop.com/files/Accumulator and Expansion Tank Instructions ZPWL4 doc595.pdf

 

Yes. And don't forget you need to switch the pump off and open a couple of taps to release the water pressure in the system before setting it. 

Edited March 22, 2021 by blackrose