224 on a Mitsubishi Heavy Industries Air-Conditioning Europe Hydrolution: Fan alarm from heat pump: Deviations in the fan speed in the outdoor unit
Short answer
On a Mitsubishi Heavy Industries Air-Conditioning Europe heat pump, 224 means: Fan alarm from heat pump: Deviations in the fan speed in the outdoor unit. The heat pump stops until the fault clears or is reset. An engineer is needed to fix the cause.
Reviewed 23 September 2026 · 1 source
What it means
The manual says: Fan alarm from heat pump: Deviations in the fan speed in the outdoor unit.
Part involved: Fan alarm from heat pump.
When it shows: Deviations in the fan speed in the outdoor unit.
Likely causes:
- Fan blocked or not connected; defective fan motor; fuse blown.
Is it safe?
| Does the heat pump stop? | Yes |
|---|---|
| Severity | Fault — needs a manual reset once the cause is fixed |
| Engineer needed? | Yes |
The heat pump stops until the fault clears or is reset.
Resetting itself: no.
Manual reset: yes (select 'reset alarm' in the alarm menu).
What you can check
- Note the alarm number/text shown on the display. Check the consumer-unit breakers/isolators for the indoor and outdoor units are on. Check the outdoor unit is not blocked by leaves, snow or ice and its drain is clear (look only - do not open the casing). On the RC-HY controller you may select 'reset alarm' once (installation manual: 'in most cases it is enough'); if the red lamp stays or the alarm returns, select 'aid mode' (if enabled) or 'add. heat only' in menu 4.2 and contact the installer.
What the engineer will check
- Per manual 'May be due to': Fan blocked or not connected; defective fan motor; fuse blown. Refrigerant/outdoor-unit work (service valves, charge, sensors Tho-R/A/D/S, LPT, 63H1, fan motor, inverter/control PCBs) must be done by an F-gas certified engineer.
Who to ask for: Heat pump / refrigeration engineer (manufacturer-trained).
Certification: F-gas certification for refrigerant-circuit work; electrical competence (Part P/18th Edition) for PCB/wiring.
What you might notice
Sources
- Installation Manual - Air to Water Heat Pump using R32 refrigerant, Hydrolution (HM) ↗ · PSC012D169 (202201) · page PDF p.80 (printed 78) · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026