Why won't my aircon turn on?

Aircon not turning on: the quick checks

When the aircon does not operate and the operation lamp stays off, Daikin's troubleshooting page lists five checks: whether the breaker has tripped or a fuse has blown, whether the power plug is connected, whether there is a power failure, whether the remote controller batteries need replacing and whether the timer is set correctly. A practical order:

1. Check for a power failure. See whether other lights and appliances still work.
2. Check the plug. If the aircon has a plug, make sure it is connected, with dry hands and nothing wet nearby.
3. Look for a tripped breaker. Look without touching anything yet; the breaker checks below explain what to do.
4. Replace the remote batteries. Fit fresh ones and try again.
5. Check the timer. Make sure no timer is keeping the unit off.

Remote and battery checks

Sometimes the fault is an aircon remote not working rather than the unit. These are practical checks, not a maker's rules:

• Fit fresh batteries the right way round.
• Point the remote straight at the indoor unit.
• Check it shows cooling mode, not fan or dry.
• Make sure no off timer is set.

For an aircon that will not operate with the lamp flashing, Daikin says to turn the aircon off, switch off its circuit breaker and wait twenty minutes, turn the breaker back on, then turn the aircon on and check the light. Do this only with dry hands and nothing wet near the breakers, and skip it if you smell burning. If the problem remains, Daikin says to contact your nearest Daikin representative; for another brand, contact the maker or your servicing company. Error codes differ by brand, so check your manual, and see our aircon blinking light guide.

Isolator and breaker checks

For aircon no power rather than a remote fault, check the isolator and breakers next. Read this first.

If it is safe, check that the isolator switch is on. HDB explains that the consumer unit (CU) holds miniature circuit breakers (MCBs) and a residual current circuit breaker (RCCB). An MCB trips on an overload or short circuit, cutting supply to its circuit; the RCCB cuts off electricity in the flat when it detects an earth current leakage.

Daikin says the aircon's dedicated breaker is in the main fuse box; if you do not know which one it is, check with your installer or a qualified electrician.

As practical guidance, not any source's rule: if a breaker has tripped and none of those warning signs is present, switch off or unplug what was running, then push the tripped switch back up once. If it trips again straight away, leave it off and call a Licensed Electrician. Never keep resetting it, tape or hold the switch up, or open the consumer unit's cover. See our power trip help and aircon tripping the power guides.

Printed circuit board (PCB) and sensor faults

If the power, isolator and breaker are fine and the unit still will not start, the fault is most likely inside it. Circuit boards, sensors and internal wiring are work for an aircon technician.

Daikin also says that if the ON/OFF button on the unit or remote does not work, you should stop operation, unplug the aircon or turn off its circuit breaker, and contact the place of purchase. Use the safety check above first.

Published aircon repair and inspection rates, as printed:

FROM THE HOMEZYPRO DIRECTORY

Published aircon repair and inspection rates

For the most common unit (per job), the lowest published rates from 11 companies run from S$40 to S$100. Each figure is one company's own advertised rate with its conditions, not a market average or a quote.

See 21 published repair or inspection rates and sources

Lowest matching advertised rate per company, in SGD as published. "From" marks a starting price and ranges are shown in full. Check the source for minimums, GST and inclusions.

Company	Service as listed	Rate	Source
Skyzone Aircon Pte Ltd	Aircon diagnosis fee (residential)	S$27.25 per visit	skyzone.com.sg
Snowflake Services LLP	Diagnostic visit (waived if you proceed)	S$30 per visit	snowflakeaircon.sg
City Cooling Pte Ltd	Checking	S$35 per unit	citycoolingengr.com.sg
A-Max Aircon	Troubleshooting	S$40 per job	amaxaircon.com
Blossom Engineering & Construction Pte. Ltd.	Troubleshooting	S$40 per job	blossomaircon.com
Coolest Aircon Service Pte Ltd	Aircon Repair	S$40 per visit	coolestaircon.com.sg
Doctor Cool	Aircon repair or troubleshooting	S$40 per job	doctorcoolsg.com
SmartCool Aircon Servicing Singapore	Troubleshooting	S$40 to S$80 per job	smartcool.sg
Thetop Aircon Service	Aircon troubleshooting repair	From S$40 per job	thetop.com.sg
Goodcool	Aircon Troubleshooting	S$43.60 per job	bestairconservicing.com
Aircon Boon	Ttroubleshooting [sic]	S$50 per job	airconsg88.com
Sky Blue Aircon Engineering Pte. Ltd.	Troubleshooting & diagnostics visit (from; waived upon repair)	From S$50 per visit	skyblueaircon.com
Jiaxing Holdings Pte. Ltd.	Onsite inspection checking fee (waived if the repair proceeds within 1 month)	S$54.50 per visit	jiaxing-aircon.sg
Heng Aircon Pte Ltd	Diagnostic check	S$60 per visit	hengaircon.com
Same Day Aircon Servicing Repair	Repair troubleshooting (fix quoted separately)	From S$60 to S$80 per job	urgentairconservicing.sg
Vois Pte. Ltd.	Aircon troubleshooting	From S$60 per unit	vois.com.sg
Airple	Aircon Troubleshooting	S$60.60 per job	airple.com.sg
Lion City Air Conditioner Services	Gas troubleshooting	S$87.20 per job	lioncityaircon.sg
Joydom Engineering Pte. Ltd.	On-site troubleshooting visit	S$100 per job	joydom.com.sg
Cool-Aire Aircon Servicing	VRF Troubleshooting - On site survey / Transport charges	S$150 per visit	coolaire.com.sg
Homeone Aircon	Compressor replacement labour, split (<3hp), parts excluded	S$600 per unit	homeone.com.sg

21 companies publish a repair or inspection line. 11 price it per job, from S$40 to S$100 per job, with S$43.60 in the middle: the middle company's own published rate, not an average. Other lines are priced per visit or per unit, and some say the fee is waived if the repair goes ahead. These are rates before parts, so ask whether the fix is quoted separately. Compare companies on our aircon repair page.

When to stop and call a professional

Get help if:

• The breaker trips again after one reset. Leave it off and call a Licensed Electrician.
• You notice a burning smell or scorch marks. Switch the aircon off at the remote and do not reset anything; call 995 if there is fire or smoke. See our aircon burning smell guide.
• The operation lamp keeps flashing. Contact the maker or your servicing company.
• There is water near the unit, the isolator or a switch. Keep away from the electrics and call a Licensed Electrician.

The Energy Market Authority (EMA) says electrical work at home, including repair or replacement of circuit breakers and replacement of switches, should be carried out or supervised by a Licensed Electrical Worker (LEW). EMA says electrical work in an HDB flat needs a Licensed Electrician, the class of LEW approved for loads of up to 45kVA. For faults inside the unit, compare aircon companies.

Questions