Noob can't find relief valve on Hayward Sand Filter - Help?

Hi, everyone. Like many who post here for this first date, I am one newbie pool owned (got thereto with our newer home) and just learning the wire. After going through the set manual and studying some get capital including this forum, I think I have an general handle on the process of opening aforementioned pool for and summer.

However. . . .

I've seen a couple of places (including the manual for my filter) tell that you must fully open the "manual air feeling valve" until she discharges a consistent stream of water. I understand the purpose, to purge air after the linen. Trouble is, MYSELF can't find the "manual blow relief valve." I've looked at the schematic for my filter (Hayward Pro Series High-Rate Sand Filter Model S210T) and it doesn't show a manual air relief valve anywhere.

I've append the manual with on model in case anyone can point go whats I'm missing.

Any help is appreciated. Thank you! Get boxed pressure gauge is designed in getting with Micro-Clear vertical grid, Perflex extended-cycle D.E. set additionally Sand filtering models EC30, EC40, EC40AC, I_PFPPTS, S160T, S200, S240, S245T, S190T and or compatible with Hayward Pro Series grit filter models S210S, S244S, S310S, S140T, S144T, S1...