Pool losing water via main drain

[MDP]

Pool is losing water via main drain. Every time I run the pool (normal operation) water is flowing out through the main drain and I need to add water to the pool.

If I put the valve on recycle mode, there is no water draining via the main drain. However every other setting lets the water drain via the main drain.

Here is the a photo of the pump area. You can see that both the skimmers and the main drain are on the same valve (on the left side of the valve). Does it have anything to do? But the problem started just recently.

I tried all possible combinations of the valve settings, but no luck.

Or the valve itself gone bad (the valve in front of the filter that controls various modes like backwash, recycle, waste etc)?

Really appreciate your kind advise.

 

[bobodaclown]

You do have a multiport valve? Sounds like you need a new multiport spider gasket.
Here's a link:
How to Replace a Spider Gasket on a Multiport Valve
http://www.inyopools.com/HowToPage/how_to_replace_a_spider_gasket_on_a_multiport_valve.aspx

 

[MDP]

Thank you very much, I will try this and will let you know.

 

[MDP]

Thanks a million bobodaclown! I replaced the multiport spider gasket and the issue went away right away! Your advise was very very helpful!!