Koeltechnicus Cat I cheat sheet

Category I covers all refrigeration equipment and systems, including hermetically sealed, permanently sealed and open systems, plus any fluorinated greenhouse gas (F-gas) quantity; Categories II–IV are restricted to defined charge and system types.

Core legal duties for certified personnel: leak checks, recovery, installation, maintenance, servicing, repair, decommissioning and refrigerant charging of F-gas refrigeration equipment; certification is personal and must be held by the technician performing the work.

Leak-check frequency (CO2e thresholds, t CO2e): 5–50 t every 12 months; 50–500 t every 6 months; ≥500 t every 3 months; a leak-detection system installed and verified reduces the interval by half (5–50 t: 24 months; 50–500 t: 12 months; ≥500 t: 6 months).

CO2e = charge (kg) × GWP; GWP values from the regulation's Annex (e.g. R-404A 3922, R-410A 2088, R-134a 1430, R-32 675, R-744 1) - always use the Annex value, not an old datasheet figure.

Records must be kept for at least 5 years and include: quantity and type of gas, CO2e of the charge, dates and results of leak checks, recovery/charging quantities, and identification of the certified company/technician.

Recovery efficiency targets before dismantling or servicing: 95% for systems with charge ≥10 kg (non-hermetic), 98% for hermetically sealed equipment; recovered refrigerant may only be reused by a certified undertaking after documented analysis/recycling.

Placing on the market bans: new equipment using F-gases with GWP ≥150 for certain domestic refrigerators/freezers and stationary refrigeration (with defined phase-down dates); recycled/reclaimed gas rules and the HFC quota phase-down apply to supply, not to on-site service.

Certification is valid for a defined period (typically 5 years per national scheme) and requires reassessment or refresher training; certificates and training attestations must be available at the workplace during inspections.

Pressure–temperature relation: at saturation, evaporating pressure fixes evaporating temperature and condensing pressure fixes condensing temperature; superheat = suction temp − evaporating saturation temp, subcooling = condensing saturation temp − liquid temp.

Typical setup targets: evaporator superheat 5–8 K for TEV systems, compressor suction superheat ≥10–20 K depending on motor cooling, subcooling 3–8 K; excessive superheat lowers capacity and raises discharge temperature.

Triple evacuation: evacuate to below 1000 micron (≈1.3 mbar), break to zero with dry nitrogen, repeat at least twice, then evacuate to ≤500 micron and hold a standing vacuum test (no rise > few hundred micron over 10–15 min) to prove leak-tightness and remove moisture.

Non-condensable gases raise condensing pressure; purge only with recovery equipment - never vent F-gas to atmosphere. High condensing pressure + high subcooling indicates non-condensables or overcharge; low subcooling with bubbles indicates undercharge.

Leak detection sequence: electronic detector at joints/valves, then soap solution or nitrogen pressure test; oxygen-free nitrogen only, never oxygen or compressed air, and pressure tests must respect the system's maximum allowable pressure (PS).

Brazing: purge the pipe with dry nitrogen during brazing to prevent internal oxidation (scale); use silver-based filler and flux only where required; pressure-test after assembly before evacuation.

Electrical and control checks: verify supply voltage/phase balance, compressor winding resistance and insulation, overload and HP/LP switch settings, and correct rotation of three-phase compressors before charging.

Maintenance records and refrigerant handling: log pressures, temperatures, superheat/subcooling, oil condition and leak-check results; recover refrigerant into dedicated cylinders (never overfill above 80% liquid by weight) and label recovered gas by type and analysis status.