Hayward pool filter - cannot get rid of air

[docktordeer]

Moved from here.
Sam,
I am unfortunately dealing with the same exact thing. I purchased a house that has a very nice pool and coincidentally the former owner has become my good friend. He only lives 10 doors up. He does not mind when i ask him questions about things. He left me with 8 total cartridge filters. Had the pool open and one day decided I should buy new filters. When I did, I bought OE from the pool store, installed them and since then I have been having air that constantly builds up into my filter dome and and will fill up repeated every 10-15 minutes. It has literally consumed more of my time....which I don't have. I would go back and forth with old filters and new filters. It would usually be ok with the old ones. I am not sure why. My filter dome is a CYP420 btw. So I thought there was no reason I should have to run old filters for my new pool. Since then I have been on this crazy mission to figure this out. The people I have paid on the side all work for the pool company and have 245 years of experience. I replaced every gasket suction side first........which ultimately led to me replacing all of the three way valves, entire check valve unit, all PVC piping where it comes into my pool house, brand new VSF filter pump. Had someone come out and do a pressure test as well. The funny thing is, one day it just worked and has been working over the last month. My water chemistry if fine, my pool is clear....all is well......until two days ago when i decided it was time to clean my filters. Removed the lid, cleaned them and put them back, turned on and AIR AIR AIR AIR AIR. This has been so frustrating. I did remove strainer lid, lubed the o ring. I have done everything and still air. tried shutting off all main water and slowly introducing shallow end skimmer suction and then deep end skimmer suction thinking that maybe I get air trapped in my lines. Everyone seems to think that the year my pool was built, that possibly they used flexible pic or tubing because it was way easier to run it to the pool house instead of using PVC. I am not sure and have no idea how to tell. As earlier mentioned during the pressure test, they dopplered and listened for air leaks, NOTHING... I AM LOST AND DO NOT WHAT TO DO.

Nick Hill. WOULD LOVE SOME HELP

 

[1poolman1]

If you open your filter, you allow a large amount of air into the system as it drains back to the pool. It is natural for all that air to have to purge or be released by you, completely normal.
Your filter tank only receives what the pump puts into it. It sounds like a suction leak. Anywhere in front of the pump, including the pump lid and drain plugs are potential sources of air. There are YouTube videos on finding a suction leak.
Nothing after the filter will be a source of air with the pump running, that would be a water leak.

 

[Bill1974]

When the pump is off does it loose it's prime? Normally air will get pushed through/out of the filter after it's been running a few minutes. Not really sure how air can build up in a filter, I would think it would be easier to push out than water. Maybe the new filter cartridges trap air better than water?

When the pressure test was performed how long did it last? very rarely with will something pass a pressure test but fail a vacuum test, but it can happen. Same way a pressure test is performed you can do a vacuum test. Instead of pressuring the line a vacuum pump pulls a vacuum on the line. And of course a gage to read the vacuum will be needed to see if it changes or holds a vacuum. If you have flex lines this could risk collapsing the pipe (if it does, it was probably already an issue).