Maintenance, repair, or replacement? Who fixes my air conditioner?

We officially have found ourselves in summer. The 100-degree days will grace us soon. One of our clients fired up the AC today – only to discover the air was tepid at best. So, what’s up?
Let me qualify this. Our client leases the building and finds himself with a couple of years until renewal. His tenancy began in 2015 – before lease rates lost their sanity, but I digress. When we originated his deal, the owner was insistent upon a triple net lease – NNN. To review, an N