11
Fujitsu Split AC
Severity:What Does This Error Mean?
Error 11 on a Fujitsu AC means the high pressure safety switch has tripped — the refrigerant pressure in the system exceeded the safe limit and the switch shut the compressor down. This is a protective measure to prevent compressor and refrigerant circuit damage. Common causes are a blocked condenser, failed outdoor fan, or refrigerant overcharge.
Affected Models
- Fujitsu ASTG Series
- Fujitsu ASYG Series
- Fujitsu AOTG Series
- Fujitsu Inverter Split AC (all models)
- Fujitsu General Split AC
Common Causes
- Outdoor condenser coil clogged — cannot reject heat, pressure rises
- Outdoor fan motor or capacitor failed — hot air recirculates around the condenser
- Airflow to or from the outdoor unit blocked by objects or poor installation position
- Refrigerant overcharged — too much refrigerant causes abnormally high pressure
- Expansion valve not opening correctly — refrigerant restricted from flowing through
- Very high ambient temperature combined with a partially degraded condenser
How to Fix It
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Switch off the AC and go to the outdoor unit.
Check that the outdoor unit has full clearance — at least 50 cm on all sides and above. Remove any objects, boxes, or vegetation that may have grown close to the unit.
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Inspect the outdoor condenser coil fins.
The aluminium fins should be mostly clear and visible. If they are packed with dust, cottonwood fluff, or seeds, clean them. With power off, rinse gently with a garden hose aimed through the fins from inside the unit outward.
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Watch the outdoor fan when you restart.
The outdoor fan should start spinning within a minute of the AC switching on. A fan that does not start, starts slowly, or stops after a few seconds points to a failed fan motor or capacitor — call a technician.
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Wait 30 minutes after turning off before restarting.
High pressure trips need time to dissipate before the system can restart normally. If Error 11 returns within minutes of restarting, do not keep trying — call a technician.
When to Call a Professional
If the steps below do not resolve Error 11, a Fujitsu technician is required. High pressure faults involving refrigerant charge levels can only be safely checked with professional pressure gauges.
Frequently Asked Questions
Can I clean the Fujitsu outdoor coil myself?
Yes, with simple precautions. Switch off power to the outdoor unit at the isolator switch or circuit breaker before touching anything. Use a garden hose on low pressure to gently rinse dust from the fins. For heavy buildup, a coil cleaning spray from a hardware store is more effective. Never use a high-pressure washer — it will permanently damage the aluminium fins.
Why does Error 11 happen more in summer?
High ambient temperatures mean the outdoor unit has less thermal gradient to work with — it has to work harder to push heat into already-hot outside air. A condenser that is slightly dirty but adequate in spring may tip over into Error 11 territory when summer temperatures peak. An annual pre-summer condenser clean prevents this.