Kaisai F2 fault code
Kaisai air conditioning
What it means
Outdoor ambient sensor (T4) open/short
The t4 outdoor ambient sensor reads open or short circuit.
Safety: Safe isolation before disconnecting sensors or working on the PCB.
UK models this code applies to
From the Kaisai service literature we hold (KAISAI FLY Inverter Series B (KWX) R32 service manual, §4 Quick Maintenance by Error Code (p.65, render-verified) + §5 Troubleshooting by Error Code) — not a scraped list.
FLY KWX-09 (KWX-09HRBI / HRBO)FLY KWX-12 (KWX-12HRBI / HRBO)FLY KWX-18 (KWX-18HRBI / HRBO)FLY KWX-24 (KWX-24HRBI / HRBO)FLY KWX-09 (KWX-09KRHI / KRHO)FLY KWX-12 (KWX-12KRHI / KRHO)FLY KWX-18 (KWX-18KRHI / KRHO)FLY KWX-24 (KWX-24KRHI / KRHO)Multi K2OC-18HFN32Multi K3OE-27HFN32Multi K4OB-36HFN32Multi K5OD-42HFN32
Now the harder half: proving what caused it
F2 names a symptom, not a root cause. In the app, the same code opens a guided investigation: what to measure first, the expected values for your exact model, and an honest verdict — including “nothing in this machine is broken” when that's what the readings say.
Watch a code get chased — free demo →