E4 Daikin — Low Pressure Alarm / LP Lockout
At a glance
- Severity
- FAULT STOP
- Domain
- AIR_CONDITIONING_SYSTEM
- Reference standard
- EN 378 / F-Gas EU 517/2014
- Product / context
- Low pressure switch actuation
What it means
Evaporating pressure drops below the minimum threshold and the controller stops the compressor to prevent vacuum operation or excessive superheat.
Probable causes
- Refrigerant leak from the circuit
- Electronic expansion valve stuck or filter drier restricted
- Poor airflow across the indoor coil
Where to start
Clean filters and indoor coil, check tangential fan operation and speed setting. Melt the ice and verify whether pressure returns to range.
Full guided diagnosis in the app
The diagnostic tree for this fault has 5 guided steps with measurements, checks and resolutions. You'll find it in HVACIQ, one of the five IndexOS apps: free, works offline.
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