What is the H/L adjustment for on top of the HVAC controller? Is it for altitude/elevation above sea level?

looking to sell my starion. I was planning on a 2jz/ls swap but dont have the funds or time for it right now and dont want it to waste away in the yard. You will need to file for a lost Title as the previous owner never did. Located in Port Neches tx. 409-749-9767. text for more info or message me. thanks guys

So I had a bad 12a turbo it was seized when I got it I put a rebuild in it (new bearings, seals etc.) I have a 1g bov hooked up to it and a cheap Manuel boost controller along with aftermarket gauge I was running 11psi of boost it worked and ran fantastic pulled hard was doing great then last night (3 days after I rebuilt it) I was racing around and did a burnout I saw my gauge during the burnout it was 9psi then got down to the next stop sign and then started going and my car wouldn't boost it

Seeing if anyone has a Synapse BOV that they are willing to part with.