This post overlaps with a fuller one: Common AC Issues in Pasadena Homes: Check These Five First.
Most air conditioner problems trace to a short list: the thermostat, a tripped breaker, a packed filter, a dirty outdoor unit, a clogged drain line, or a refrigerant leak. Check them in that order. The first five are safe to handle yourself around Pasadena, CA. The last one is a licensed tech's job.
The quick checks
- Thermostat. Blank screen means batteries. Otherwise confirm cool mode, fan on auto, and a setpoint below room temperature.
- Breaker. A tripped AC breaker sits in the middle. Push it fully off, then on. Once. If it trips again, leave it off and call.
- Filter. The most common cause of warm air. Hold it to a light; if you cannot see through it, replace it. Summer dust here can load one in a month.
- Outdoor unit. Power off at the disconnect, rinse the fins gently with a hose (never a pressure washer), and clear a couple of feet around it.
- Drain line. Water at the indoor unit usually means a clogged condensate line. Pull the clog with a wet/dry vac at the outlet outside.
The signs that need a tech
Ice on the copper lines or a hiss on a hot day means low refrigerant, and low refrigerant means a leak. Topping it up without finding the leak just repeats the problem and overworks the compressor. Handling refrigerant requires EPA certification. A breaker that trips twice, an outdoor unit that hums without the fan spinning, short cycling, or a burning smell also belong on the call list.
Repair or replace
Capacitors, contactors, motors, and drain faults are worth fixing on most systems. A failed compressor on an old unit, or a leak on an R-22 system, usually is not. A diagnostic visit puts both numbers in front of you, and spring maintenance catches most of this before summer.
The full guide: Common AC Issues in Pasadena Homes: Check These Five First.
Book a $69 diagnostic at Boost Services at 818-277-5056 or send us a message. The fee is credited toward the work.
Written with AI assistance by Boost Services, Heating and Cooling team, and reviewed by our licensed technicians before publishing. Boost Services Heating and Cooling, C-20 #1119892.