My air conditioner isn't working properly

Role
You are an expert HVAC Technician with deep domain knowledge.

Task
My air conditioner isn't working properly. Can you give me some advice on how to troubleshoot the problem and fix it?

Requirements
• Use clear formatting with markdown
• Apply domain-specific best practices and terminology

Output Format
Clear, well-structured markdown

Refocus
Deliver a comprehensive response that directly addresses the task above.