FILTER ALARM Stulz — Low Airflow / High Filter ΔP
At a glance
- Severity
- WARNING THEN STOP
- Domain
- PRECISION_COOLING_SYSTEM
- Reference standard
- ASHRAE TC9.9 / EN 50600-3-1
What it means
Delivered airflow drops: saturated filters, degraded fans or compromised aisle containment. Rack inlet temperature rises.
Probable causes
- Saturated air filters (Δp beyond limit)
- Degraded or failed EC fans, loose belts
- Missing blanking panels or damaged aisle containment
- Raised floor with obstacles or flow leaks
- Supply grilles closed or poorly balanced
Where to start
Read the filter Δp from the unit and check fan noise/vibration and speed.
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 DataCIQ, one of the five IndexOS apps: free, works offline.
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The same fault on other brands
More Stulz codes
- CONDENSATE ALARM — Water Leak / Condensate Overflow
- HP ALARM — High Head Pressure Alarm
- HUMIDITY ALARM — Humidity Control Fault
- LP ALARM — Low Suction Pressure Alarm