LA on a Mitsubishi Electric Ecodan: Pressure sensor failure
Short answer
On a Mitsubishi Electric heat pump, LA means: Pressure sensor failure. 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: Pressure sensor failure.
Part involved: Refrigerant pressure sensor (FTC side).
When it shows: Pressure sensor signal abnormal.
Likely causes:
- 1 Connector/terminal wire detached or loose; 2 Pressure sensor fault; 3 FTC board failure.
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: Not stated as auto-resetting; code remains until reset.
Manual reset: Installation manuals: press F4 (RESET) then F3 (Yes) on the main remote controller (older controllers: hold button E for 3 s); 'To cancel error codes please switch system off'. Fix the cause first.
What you can check
- Note the code, unit and ref. address shown on the main remote controller and contact your installer (Mitsubishi user manuals: 'Make a note of the error code number and contact installer'). Check the heat pump breaker/isolator at the consumer unit is on and read the primary system pressure gauge (if fitted) so you can report it. A single reset from the main remote controller (RESET, then Yes) may be tried; if the code returns, do not keep resetting. Do not open the outdoor unit, cylinder/hydrobox or any casing.
What the engineer will check
- 1 Check pressure sensor cable for damage or loose connections; 2 Electrically test sensor; 3 Replace board.
Who to ask for: Mitsubishi Ecodan-trained heat pump engineer (controls / wiring).
Sources
- Ecodan EHPT20X-MEHEW Service Manual (OCH814A) ↗ · OCH814A · page 62 (10-4 Self-diagnosis and action) · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026