Which situation matches?
Thermostat settings changed
Check the mode, target temperature and schedule against the manual.
An accessible filter is dirty
Use the approved filter procedure; do not remove equipment covers or improvise a denser filter.
There is ice, burning smell or repeated shutdown
Stop routine troubleshooting and contact a qualified HVAC contractor. Do not chip ice or work on refrigerant components.
Prepare for the next step
Thermostat instructions, flashlight and a record of symptoms. Check safely from outside the equipment enclosure.
Record when the symptom began, what changed and which observations you can make safely. Do not dismantle equipment simply to provide a more detailed description.
Follow the full guide
Air conditioner running but not cooling: first checks
The full guide explains the safe procedure, mistakes to avoid, professional stopping points and prevention. Browse supporting publisher tutorials, or use the moderated Q&A for a non-urgent question.
Sources and limits
Documentation checked November 4, 2026. AI-assisted educational content; no property inspection or licensed professional review is claimed.