Hardware Model Specification
Mitsubishi Electric Ecodan PUZ-WZ R290 Monobloc Series Diagnostics
Classification: HVAC & Heat Pumps Equipment
Hardware operational fault codes, protection alarms, LED blink sequences, and step-by-step diagnostic fixes for the Mitsubishi Electric Ecodan PUZ-WZ R290 Monobloc Series.
1 Documented Faults
•
Full Multimeter & Safety Isolation Procedures
Indexed Fault Codes for Ecodan PUZ-WZ R290 Monobloc Series
Step-by-step resolution manuals and root cause matrices
CODE P8
Severity: Critical
Difficulty: Advanced
Heat Exchanger Freeze Protection Lockout
The P8 fault indicates an active freeze protection lockout on the plate heat exchanger (HEX). The outdoor controller detected water or plate surface temperatures dropping below safety limits (typically < 3°C to 5°C) during heating, cooling, or defrost modes, triggered to prevent catastrophic rupture of the brazed plate exchanger by expanding ice.
⏱ 45-60 Mins
Troubleshoot Now →