F29 on a Panasonic heat pump: Low Discharge Superheat
Short answer
On a Panasonic heat pump, F29 means: Low Discharge Superheat. 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: Low Discharge Superheat.
Part involved: Discharge temperature sensor; discharge pressure sensor; pressure switch.
When it shows: During startup and operation of cooling and heating, the temperatures detected by the outdoor pipe temperature sensor are used to determine sensor error. Service-manual table judgement: 1 times occurrence within 2550 minutes (K, J MDC, J AIO, H).
Likely causes:
- 1 Faulty connector connection. 2 Faulty sensor. 3 Faulty outdoor unit PCB (main). 4 Faulty High Pressure Switch 5 Refrigerant shortage (refrigerant leakage).
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 in the Panasonic documents opened; protection counters lock out after the stated number of occurrences.
Manual reset: User: 'Error Reset' in the remote-controller Quick Menu (H/J/K/L controllers) or OFF/ON; engineer must clear the underlying cause (service manuals: 'When error happens, the power has to be reset').
What you can check
- Read and note the code shown blinking on the remote controller (also stored under System Check > Error history). Per the Panasonic operating instructions the user may switch the system OFF/ON at the remote controller and use 'Error Reset' in the Quick Menu; if the code returns, leave the system and contact the installer (UK user guide lists Panasonic technical support as the fallback).
What the engineer will check
- Check discharge temperature and discharge pressure sensors; check pressure switch; check refrigerant charge; check outdoor PCB.
Who to ask for: F-gas certified refrigeration / heat pump engineer (Panasonic-trained).
Certification: UK F-gas certification (Category I) for any refrigerant-circuit work; flammable-refrigerant competence for R32 (J/K) and R290 (L/M) units.
What you might notice
Sources
- Service Manual Hydromodule+Tank WH-SDC0309K3E5/K6E5 with WH-UDZ03KE5/05KE5/07KE5/09KE5 (Order No PAPAMY2306062CE) ↗ · PAPAMY2306062CE · page 222 (error codes table); 262 (self-diagnosis) · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026