Technical guidance for central air-conditioning refrigeration equipment maintenance process-wide
(covers core subsystems such as screwrs, centrifuges, cooling towers)
I. Pre-maintenance safety and diagnostic norms
It's a safety code
Refrigerants require certified induction (epa 608), self-contained respirators (scba) and anti-frozen gloves5
Electrical operations executing "lockout/tagout" program: blackout of electrocution to mark 1
Limited space operations (e. G. Cooling towers) need to detect oxygen concentrations (19. 5% thorium) and harmful gases3
Three pieces of ax
Fault priority detection entry tool
Infrared thermal imager with less refrigeration than evapotranspirers close to temperature (>3°c anomaly)
The compressor frequently suspends the pressure differential (<1. 5 bar alarm) transmission device
Unusual vibration (>7mm/s) yi
Ii. Technical details of maintenance of core components
1. Compressor maintenance (helicopter/ centrifuge)
Point of the screw-up:
Rotation rehabilitation: detection of condensation gap (standard 0. 08-0. 15 mm), excess required grinding or replacement
Axle seal replacement: pre-refrigerated oil immersed seal, rectangular stifling to 35n m2 by cross-cutting method
Slide valve calibration: 10% current fluctuations at 25-75% energy reconciliation
Special maintenance of centrifuges:
Pneumatic treatment: cleaning of leaf implementing agencies, re-marking of the pneumatic contour (15% glyphs)
Leaf wheel balance: field weight at vibration value > 7. 1 mm/s (residual imbalance ≤1g. Mm/kg)3
2. Heat exchanger depth maintenance
Bronze leak:
Preserve up to 1. 5 times the design pressure coated with hair bubbles (focus detection of u-shaped bends)
Single leaks are blocked (10% of blockage total)6
Chemical cleaning:
Slurpant type formula temperature/time
8% carbonate + 50°c/cycle 4 hours
Biomixed mud season ammonium salt microbicide (at 200 ppm) constant temperature/cycle for 6 hours
3. Treatment of cooling tower systems
Criteria for filling replacement:
Material flaring (powdered by hand) or grave thickness >2mm needs to be replaced as a whole
New filling flame retardation level b1, pvc tablet 0. 35 mm5
Water turbine modifications:
Replacement of traditional electric power, 30-40 per cent energy efficiency driven by backwater pressure
Import pressure requires 0. 25 mpa, traffic matching design value > 5%7
Refrigerant and lubricants management
Refrigeration of gold
Vacuum up to 500 m, 24-hour pressure down < 0. 5 psi eligible
R134a 280(2)(8kg) 2
Lubrication system controls
Standard centrifuge standard for parametric screwrs
Viscosity (40°c) iso vg 68±10% iso vg 46±5%
Acid value (mgkoh/g) <0. 5 <0. 3
Water (ppm) <100 <50
Replacement period: screwr 8,000 hours/circle 12,000 hours4
Electrical and control failures
1. Typical failure management
The electric overheating (>125°c):
Detection of cooling circuit traffic (circle 45l/min)
Verify three-phase imbalance (<5%)1
Plc's offline:
Inspection of terminal resistance (120)
Replacement of the profibus double-crowding line (110 times x 10 per cent)8
2. Elements of frequency changer maintenance
Oc overflow
Ov overpressure
Oh overheat
Fault code
Type
Testing igbt modules
Check the brakes
Clean up windways + replace fans
Preview
Oc overflow
Ov overpressure
Oh overheat
Fault code
Type
Testing igbt modules
Check the brakes
Clean up windways + replace fans
20% capacity reduction needs to be replaced (euro)
Increased electrical insulation 3 at carrier frequency > 8khz
V. Post-maintenance certification standards
Performance test matrix
Project conformity detection method
Refrigeration gill 95% difference (gb/t 18430)
Cop (energy efficiency ratio) > 4. 8 (centrifugal)/ > 4. 2 (helix) power meter + flow count
Vibration speed (rms) <4. 5 mm/s vibration analyser iso 10816-3
Long-lasting management measures
Establishment of a three-dimensional digital twin model: real-time mapping of 12 parameters such as oil temperature, vibration, etc
Implanting predictive maintenance systems: 14 days early warning failure via ai algorithm (>85%)6
Case warning: a centrifuge lost $1. 2 million due to its neglect of the oil quality test (the acid value was 1. 2mgkoh/g), resulting in the burning of the bearings. Strict implementation of the programme would reduce the rate of major repairs by more than 40 per cent and extend the life of equipment by 8 to 10 years。
Annex: list of maintenance tools
Precision instruments: laser pairing medium, chiller recycler (90 per cent recovery rate for thallium), axle heater
Security equipment: gas masks (3m 6900), electric arc suits (cat class 4)
Spare parts for consumables: o-cycle (fluorinated rubber) and specially designed refrigerated oil (e. G., interest 08w-1001)。
Hangzhou carey engineering ltd., a technical service company engaged in air-conditioning refrigeration and heating equipment, has many heating engineers, advanced and electrical engineers。
Kerry's main technical staff are the technical engineers of the domestic and foreign air-conditioning refrigeration company's original plant, with many years of experience, deep-seated technology, client-oriented and people-centred beliefs。
