• The brand and/or model number of you unit
• The age of your indoor and/or outdoor unit
• Who installed the unit?
• When was it last serviced and who last serviced it?
• When were the filters last changed?
• Are the indoor and/or outdoor fans blowing?
• Did you check your circuit breakers to make sure none were tipped?
• Is your unit making an odd noise?
• Are there any unusual odors?
• Was there any unusual weather activity before the equipment started having trouble?
• Are there any unusual fluids leaking around the unit?