Air relief question

[fjzsocal]

I have a very old 48 sqft American Products/Pentair DE filter. There seem to be no air relief parts inside, just a hole in the lid for the pressure gauge, and a petcock installed between the lid and gauge to let air out.

Is this good enough?
Why do new filters have hoses from the manifold to the ceiling of the lid?
Am I right in assuming that only the dirty side of the filter needs air relief?

I'm getting DE/debris back in the pool, trying to figure out why and realized I don't understand the air relief...

 

[HermanTX]

As you can see you have air bubbles form in your pump basket. This occurs when you open to clean your pump basket. Also, when you turn on a pump it may prime and have some air it pushes to the filter. The filter operates best when it is full of water. The water goes to the outside of the grid, passes through the DE filter cake and the grid itself to the inside of the grid and then flows out of the filter back to the pool. The grid and DE filter cake captures all the debris. The air relief at the top of the filter allows you to remove that air that forms and provides more efficiency to the filter. Think about it, If the filter was half full of air then the water flow would only be through half of the filter grids. So you want to have a filter full of water and minimize any air in it that may accumulate. Hope this helps.

 

[fjzsocal]

Thanks Herman I appreciate the answer. What I'm not sure about is whether an air relief is anything more than a hole in the top with a valve, and also whether the air should be bled from the dirty (before DE) or clean (after DE) side of the filter.

 

[HermanTX]

Thanks Herman I appreciate the answer. What I'm not sure about is whether an air relief is anything more than a hole in the top with a valve, and also whether the air should be bled from the dirty (before DE) or clean (after DE) side of the filter.

I am probably not following your request. I am not understanding what you are trying to connect and it maybe because you have as you say - a very old filter. Maybe a picture will help.
The air relief on top of a filter is only releasing air from the dirty side of the filter.

If you are getting DE and debris back in the pool then you may have a hole in the filter grid or in the manifold that holds all the grids together. That manifold directs the flow once it passes through the grid back to the pipe that exits the filter to the pool.
The DE should form a cake on the external part of the grid to create a barrier to retain very fine particles as the flow passes through it to the internal part of the grid.

My Pentair DE filter which was more than 15 years old works that way. So if yours is different, then pictures and model numbers would help.

 

[fjzsocal]

I'm just trying to get a basic understanding of the air relief system, which you've given me. Now that I understand what's going on with it, I can troubleshoot the DE/debris problem.

thanks for your answer.