Exchange 2013 IIS App Pool 'Idle Time-out Action Value'

Exchange 2013 CU22 -- Resource Exhaustion issue causing the Databases to fail over.

RAM --32GB

IIS 8.5

I can see that the WP "24940" (applicationPool:MSExchangeECPAppPool),(WP "18404" (applicationPool:MSExchangePowerShellAppPool) causing the issue with high Memory. 

Investigating the application pool I can see that the 'Default Application pool' "Idle Time-out Action Value" is set to 20. ( which i believe is the default value. But Any of the Application Pools in Advanced settings the Value=0

I'm trying to understand what this means. do the single Application Pool actually time out at 20 minutes. Is there any Microsoft documentation specific to this scenario. I've checked in a couple of Exchange 2013 and it seems the same across.

The documentation does not mention actually that if the 'Default Application pool' is 20 and lets say the 'MSExchangeECPAppPool" is set to 0 if it still means it will time out after 20 minutes.

I'd like to get to the bottom of this before starting Recycling etc.

Thanks in Advance