Air conditioner will not start or keeps stopping
Before blaming the compressor, distinguish a unit that does not respond, an active schedule and a shutdown accompanied by an error indication.
Record what actually happens
Does the remote display work? Does the unit acknowledge the command? Do any indicator lights appear? Note whether one unit or the whole installation is affected. A picture of an indicator is usually more useful than pressing the power button repeatedly.
Check user controls only
Check batteries and timers as described in the manual. A weekly schedule, app or another controller may explain unexpected starts. If the unit repeatedly starts and stops, record the approximate cycle length and room temperature; never bypass sensors or protections.
Do not force electrical protection
If a breaker or residual-current device trips, do not repeatedly reset it or move the equipment to another circuit as a test. Stop using the system and request inspection. Burning smells, sparks or damaged wiring require stopping use; the absence of a displayed error does not mean that further attempts are safe.
Choose the next step
Use the symptom page to understand the likely causes. If the cause is still unclear, book a diagnosis before approving a repair.