F6
Carrier Split AC
Severity: MinorWhat Does This Error Mean?
F6 on a Carrier AC means the drain pump motor or the drainage float switch has detected a fault. This code is triggered when water in the drain pan rises too high — either because the drain line is blocked or the drain pump has failed. The AC shuts down to prevent water from overflowing into the room.
Affected Models
- Carrier Ester Plus
- Carrier Superia Plus
- Carrier Durafresh Neo
- Carrier Inverter Split AC (all models)
- Carrier Esko Plus
Common Causes
- Condensate drain pipe blocked with algae, mould, or debris
- Drain pump motor failed or impeller jammed with debris
- Drain float switch stuck in raised position, triggering F6 even when drain is clear
- Drain pipe incorrectly routed — upward loop preventing drainage
- Drain tray cracked, causing leakage before reaching the pump inlet
How to Fix It
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Switch off the AC immediately.
Check below and around the indoor unit for water dripping inside the room. F6 means the drain pan is close to overflow level.
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Find and clear the drain pipe.
The condensate drain pipe exits the indoor unit (usually a 16–20mm plastic pipe) and leads outside or to a drain point. Use a wet/dry vacuum at the pipe exit to suck out the blockage, or blow compressed air gently from the exit end back toward the indoor unit.
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Clean the drain tray.
Remove the indoor unit front panel and wipe out any algae or slime from the plastic drain tray. A diluted bleach solution kills algae and prevents future buildup.
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Restore power and restart.
If the drain was blocked, F6 should clear once the pan empties. Monitor for any continuing drip.
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If F6 persists after clearing the drain, call a technician.
The drain pump motor or float switch may have failed and require replacement.
Frequently Asked Questions
How do I stop Carrier F6 from happening repeatedly?
The most reliable prevention is monthly drain maintenance during the cooling season. Pour one tablespoon of diluted household bleach into the drain tray access point — this kills algae before it builds into a blockage. Also ensure the drain pipe has a continuous downward slope from indoor unit to exit point with no upward loops.
Is water dripping inside my room dangerous?
Water dripping inside the room can cause damage to walls, ceilings, flooring, and nearby electrical fittings. Switch the AC off immediately if water is dripping inside — do not just ignore F6 and let it run. Clear the drain before restarting.