12 Fujitsu — Capacity unbalance between circuits
At a glance
- Severity
- WARNING
- Domain
- VRV_VRF_system
- Reference standard
- EN 14511, ASHRAE 90.1
- Product / context
- Discharge temperature too high
What it means
The VRV/VRF system shows a significant capacity imbalance between different circuits or branches. Some indoor units reach the setpoint while others remain far from it. The system cannot balance the thermal load between compressors, causing inefficient operation and reduced comfort.
Probable causes
- Very different piping lengths between system branches
- Incorrect sizing of indoor units relative to the thermal load
- EEVs of some indoor units with incorrect opening or stuck
- Branch controller with partially obstructed valves
- Very dirty air filters on some indoor units reducing capacity
Where to start
Check EEV opening of each unit from the service panel. Inspect air filters of units that do not reach the setpoint. Verify that the units are sized for the thermal load of the zone.
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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