Am I missing a check valve?

[Killer95Stang]

Today I removed my SWG to check for calcium buildup (was pretty clean, even with 490 CH). The short time it was off, I could hear my whole system filling with air, meaning all the water in the system was draining back into the pool. Not really an issue, except for the fact that it pulled a bunch of DE powder from the filter with it. When I looked down at the bottom of the pool I could see where the DE powder was coming back into the the pool from the floor drains and skimmer.

So, am I missing a check valve to prevent this, or do I have to turn a valve to closed? My pool was a sparkling 61 degrees... and now its a little cloudy from the DE powder.

 

[duraleigh]

I can't tell, do you have a multi-port on the top of your filter?

 

[JamesW]

Because of this, I always like to have a check valve between the pump and filter. If you remove the pump lid a few minutes before allowing air into the system from after the filter, that will usually help. Alternatively, you could close the three way valve in front of the pump to prevent backflow.

Note: The filter has a slide valve. The part on top of the filter is a data cable that goes to an Intelliflo.

 

[mas985]

A check valve after the filter would serve the same function and it is less likely to have debris cause leaks.

 

[malcolmb5325]

you wont need check valves as you have a 3 way in front of your pump which you should close off first before opening pump lids, swc's etc. It also looks like you have ball valves and 2 way valves on the return to pool lines which you close off. But remember to turn them back open once you have done the work.