Air in the filtration system

[mikethaisun]

Hello Everyone
I have a problem with excessive air in the filtration system that is causing problems when trying to vacuum the bottom of the pool. It can take up to 20 minutes for the air to be syphoned off through surface bubbles before the vacuum works efficiently.
I have a sand filter and water passes through it by using 4 valves. No' 1 and 4 are opened to use the vacuum. No' 2 and 4 are opened to filter the pool water, No's 3 and 4 are opened to top up the pool. Number 3 is opened to backwash.
In the top of the pump there is an inspection glass that shows the strainer basket content and this is invariably low on water causing the pump to seem to labour until sufficient water is in the strainer to enable the pump to work efficiently with a good flow of water passing through it.
Does anyone have any advise on how to get rid of the excessive air? I have checked the flexible vacuum hose for holes and can find none.
Regards to all
Mike

 

[Richard320]

My pump can push water out faster than it can pull it in through the vacuum hose. So I get that same starvation thing in the filter basket and it gets noisy. I open the other valve and draw some water from the spa - just enough to keep the basket full. I haven't done it enough to know for sure yet if it sweeps better with 100% suction on the hose or 100% water in the basket, but the pump is certainly quieter.

 

[coloeb]

Try this , close vacume line and open the normal valves for water circulation, start pump. SLOWLY open vacume line and watch the water level in the pump strainer. you will see bubbles but not more than a min or 2 at the most. when the hose is primed your vacume hose should be laying on the pool floor not floating .
If the air is not removed withing 2 to 3 min. you are likely sucking air from some place. If you are certian the hose has no leaks check the area where the hose connects to the piping, mine likes to suck air there so I have 2 clamps for that reason. When the vacume is sucking correctly set the valves to thier correct position.

 

[mikethaisun]

Try this , close vacume line and open the normal valves for water circulation, start pump. SLOWLY open vacume line and watch the water level in the pump strainer. you will see bubbles but not more than a min or 2 at the most. when the hose is primed your vacume hose should be laying on the pool floor not floating .
If the air is not removed withing 2 to 3 min. you are likely sucking air from some place. If you are certian the hose has no leaks check the area where the hose connects to the piping, mine likes to suck air there so I have 2 clamps for that reason. When the vacume is sucking correctly set the valves to thier correct position.

Hello Coloeb
Thanks for the advice. My system has two valves for vacuuming and two valves for filtering. I have tried as you suggested with no immediate improvement. When you say slowly open the vaccuum line does that mean open both vacuum valves inlet and outlet through the filter?
I did notice that air was leaking through the top of the strainer glass cover so may be I will buy a new rubber gasket.
Thanks
Mike

 

[mikethaisun]

My pump can push water out faster than it can pull it in through the vacuum hose. So I get that same starvation thing in the filter basket and it gets noisy. I open the other valve and draw some water from the spa - just enough to keep the basket full. I haven't done it enough to know for sure yet if it sweeps better with 100% suction on the hose or 100% water in the basket, but the pump is certainly quieter.

Hello Richard
Thanks for the advice, it sounds as though we have the same problem, I am not sure which valve you think I should open as I have two for filtration and two for vacuum. 1 & 4 are for vacuum and 2 and 4 are for filtration, Valves 1 and 2 are the outlet valves from the pool to the filter.
Thanks
Mike