1. Scope and purpose
This manual describes the standardized maintenance of industrial ventilation systems in production environments. The focus is on the integrity of the duct system, the functionality of the throttle and butterfly valves, and the calibration of the air quality monitoring. Proper maintenance is critical to comply with workplace limits, to avoid fire risks due to dust deposits and to optimize energy efficiency in accordance with DIN EN 13779 and VDI 6022.
2. Safety instructions
DANGER: Before starting any work on the ventilation system, the system must be completely switched off and secured against being switched on again (Lockout/Tagout - LOTO). Make sure that there is no stored energy (e.g. rotating fan wheels with overrun, electrical capacitors in frequency converters). Wearing personal protective equipment (PPE) - consisting of S3 safety shoes, safety glasses, hearing protection and respiratory protection (min. FFP3) when working in contaminated areas - is mandatory.
3. Tools and materials
| Tools/material | Specification | quantity |
|---|
| Torque wrench | 5 - 50 Nm | 1 |
| Differential pressure gauge | 0 - 5000 Pa | 1 |
| Laser escape tool | For shaft alignment | 1 |
| Industrial vacuum cleaner | H class (for hazardous dust) | 1 |
| multimeter | True RMS Value (TRMS) | 1 |
| sealant | Silicone-free, temperature-resistant | 1 |
4. Pre-maintenance checklist
| Element | Exam | criterion | Remark |
|---|
| Canal system | Visually inspect for corrosion/leaks | No cracks or material removal | Check at connection points |
| Flap drive | Manual operation | Movement without resistance | Check lubrication status |
| Filter media | Differential pressure measurement | Values within manufacturer specifications | Exchange at > 250 Pa |
| Sensors | Zero point check | Values plausible | Carry out reference measurement |
5. Step-by-step maintenance procedures
- Backup and Preparation: Perform LOTO. Disconnect all electrical connections to the damper actuators and fan motors. Error: Neglecting the residual energy in the fan wheel.
- Inspection of the sewer system: Open inspection openings. Remove deposits with the industrial vacuum cleaner. Check flange connections. Tighten screws (M8) to 20 Nm. Error: Over-tightening causes deformation of the flange gaskets.
- Maintenance of the damper control: Clean the damper blades and axle bearings. Lubricate bearing points with high-temperature-resistant grease (e.g. based on lithium complex). Check the fit of the flap in the closed position (gap size max. 0.5 mm).
- Calibration of air quality monitoring: Clean the sensor surfaces with compressed air (max. 2 bar). Carry out a zero point adjustment for CO2 sensors (reference value: fresh air ~400 ppm). Error: Using cleaning agents containing solvents damages the sensor membrane.
6. Verification after maintenance
| test | Expected result | Actually | Pass/Fail |
|---|
| Leak test | No audible leaks at nominal pressure | - | - |
| Flap running time | Open/close within < 30 seconds | - | - |
| CO2 value | Stabilization at setpoint | - | - |
7. Troubleshooting
| Symptom | Probable cause | Corrective action |
|---|
| The flap is stuck | Dirt or bearing defect | Clean and re-grease |
| High differential pressure | Filter added | Replace filters |
| Fluctuating CO2 levels | Sensor dirty | Clean or replace sensor |
8. Maintenance schedule
| task | Frequency | Duration | Qualification |
|---|
| Filter inspection | Monthly | 30 mins | Technician |
| Flap lubrication | Semi-annually | 60 mins | Technician |
| Sensor calibration | Annually | 120 mins | Technician/specialist |
9. Spare parts reference
| Description | Specification | UNITEC category |
|---|
| Damper actuator | 24V AC/DC, 10 Nm | Ventilation technology/drives |
| sealing tape | EPDM, self-adhesive | Ventilation technology/accessories |
| CO2 sensor module | 0-2000ppm, 0-10V | Sensors/monitoring |
Order the spare parts you need directly via our UNITEC-D e-catalog.
10. References
- DIN EN 1505: Ventilation of buildings – sheet metal air ducts
- VDI 6022: Indoor air technology, indoor air quality
- DIN EN 13779: Ventilation of non-residential buildings
