Why won't my aircon turn on again after a service visit?
A unit that will not wake up after a service is usually not broken. Power was interrupted to work on it safely, and something about restoring that power was left unfinished.
By Team Snowflake | Updated 19 Aug 2026
1. Isolator never switched back on
A unit that is completely dead, with no light and no beep, most often has no power reaching it. The isolator is switched off so the unit can be cleaned safely. Once the work is finished it has to be flipped back. On a busy day that last step gets missed.
How to tell
This path has no power at all. Unlike a board that lost its state, there is no light, no beep and no response of any kind. Nothing electronic is running to fail.
- Nothing at all happens, no light and no beep.
- The remote gets no response of any kind.
- It worked perfectly right up until the service visit.
- The isolator switch near the unit is in the off position.
How we confirm it
We confirm supply at the isolator and restore it. The unit then runs through a full cycle to make sure nothing else was disturbed during the work.
Do not pay a call-out for a board before the isolator has been checked. A unit with no supply behaves exactly like a failed board, and the check takes seconds.
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2. The board lost its state when power was cut
A unit that powers up but will not run properly, or shows an error straight after a service, may have had its supply cut while it was still running. Switched off through the remote, the board shuts down in order and saves a clean state. Cutting the isolator mid-run does not give it that chance.
How to tell
This path has power. Unlike an isolator left off, lights come on and the unit reacts to the remote. The fault is in what the board remembers rather than in whether it is being fed.
- Lights come on, so power is clearly reaching it.
- It shows an error, or responds but will not start cooling.
- The problem began the moment the service ended.
- The isolator was cut while the unit was running.
How we confirm it
We power the unit down cleanly, allow the board to clear, then restore it in the correct order. The unit is run through a full cycle afterwards to confirm the state has recovered.
Do not let a board be replaced on this symptom alone. A board that lost its saved state looks like a failed one, and a clean power cycle in the right order costs nothing to try first.
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Tell us what’s going on. Symptoms, setup, photos, anything we should know. We’ll assess and come back with the right next step.