1. Maintenance technology of central air-conditioning system:
1. Maintenance of air conditioners and fan coils;
2. Maintenance of air-conditioning main units;
3. Terminal equipment maintenance services;
4. Air conditioning cooling tower maintenance services.
2. Central air conditioning cleaning:
1. Refrigeration units, cooling towers, hot and cold water systems, air conditioning systems, and circulating water systems;
2. Heat exchange equipment, condenser, evaporator, cooling water system, refrigerant water system in the refrigeration unit;
3. Fan coil surface cooler, condensate water pipeline equipment.
3. Central air conditioning maintenance:
1. Air conditioner and fan coil maintenance;
2. Host system: compressor, vacuum valve, sight glass , canned pumps, vacuum pumps, heat transfer tubes, condensers, evaporators, automatic control components;
3. Cooling tower: fans, bearings, water distributors, filters, membrane materials, tower components, etc.
IV. Service content
1. Develop a year-round central air conditioning operation and maintenance work plan for you;
2. Regularly inspect the host and terminal equipment;
3. Repair, modify, replace parts and assemble;
4. Inspect compressors and provide oil change services;
5. Handle customer inquiries at any time For emergencies such as disassembly and central air conditioning, we will rush to the scene within 2 hours after receiving the repair notification;
6. Year-round adjustments due to seasonal temperature differences will bring changes to the system.
7. Preventive maintenance and minor repairs, including repair and replacement of frequently worn parts;
8. Complete daily operation and routine maintenance of central air-conditioning equipment every month and day Cleaning work;
9. Monitor, record and archive the equipment, water quality and air quality of the air conditioning system, and issue a detailed report for each inspection and maintenance.
1.0 Purpose
Standardize the maintenance and repair work of central air conditioners to ensure that all functions of central air conditioners are intact.
2.0 Scope of application
Applicable to the maintenance and repair of various types of central air conditioners within the jurisdiction of property management companies such as hotels, office buildings, major supermarkets, etc.
3.0 Responsibilities
3.1 The manager in charge is responsible for reviewing the "Annual Plan for Maintenance of Central Air Conditioning" and inspecting the implementation of the plan.
3.2 The technical department is responsible for organizing the formulation of the "Annual Plan for Maintenance of Central Air Conditioning" and organizing and supervising the implementation of the plan.
4.1 Principles for formulating the "Annual Plan for Maintenance and Maintenance of Central Air Conditioning":
a) Frequency of use of central air conditioning;
b) Operation status of central air conditioning ( Hidden faults);
c) Reasonable time (avoiding holidays, special event days, etc.).
4.2 The "Annual Plan for Maintenance and Maintenance of Central Air Conditioning" should include the following contents:
a) Maintenance items and contents;
b) Specific implementation of maintenance Time;
c) Estimated cost;
d) Spare products and spare parts plan.
4.2.1 Maintenance of central air conditioners should be carried out in accordance with the "Annual Plan for Central Air Conditioning Maintenance and Maintenance".
4.2.2 Refrigeration technicians are responsible for daily maintenance of central air conditioners, major repairs of central air conditioners and troubleshooting of PC central processors.
4.2.3 Cooling tower maintenance.
4.2.4 Use a 500V megohmmeter to detect the motor insulation resistance and it should not be less than 0.5MΩ. Otherwise, the motor coil should be dried. If it still cannot reach above 0.5MΩ after drying, the motor coil should be dismantled and repaired.
4.2.5 Check whether the motor and fan rotate flexibly. If there is any blockage, add lubricating oil; if there is abnormal friction sound, replace the bearing with the same model and specification.
4.2.6 Check whether the belt is cracked or severely worn. If so, replace the belt with the same specification; check whether the belt is too loose. If so, adjust it (check once every half month); check the fit of the pulley and the shaft. Is it loose? If so, it should be repaired.
4.2.7 Check whether the water distributor distributes water evenly. Otherwise, the pipes and nozzles should be cleaned.
4.2.8 Clean the cooling tower (including filler and sump) and clean the fan blades.
4.2.9 Check whether the water replenishment float valve operates reliably, otherwise it should be repaired (irregularly).
4.3.0 Tighten all fasteners.
4.3.1 Clean the entire cooling tower exterior.
4.3.2 Fan coil maintenance: Refrigeration technicians should clean and maintain the fan coil every six months.
4.3.3 Clean the air filter once a week to remove the air in the coil (irregularly).
4.3.4 Check whether the fan rotates flexibly. If there is any blockage, add lubricating oil. If there is abnormal friction noise, replace the fan bearing.
4.4 Cabinet evaporator maintenance:
a) Clean the air filter once a week;
b) Clean the evaporator fins;
c) Clean the drain pan.
4.5 Water-cooled condenser and evaporator maintenance (dirt removal):
a) Prepare 10% hydrochloric acid solution (add 0.5g corrosion inhibitor per 1kg acid solution);
b) Disassemble the condenser and evaporator, seal the water inlet and outlet flanges at both ends, and then fill them with acid solution. The pickling time is 24 hours. It can also be cleaned with an acid pump cycle, and the cleaning time is 12 hours;
c) After pickling, clean with 1 NaOH solution or 5Na2CO3 solution for 15 minutes, and finally rinse with clean water more than 3 times;
d) After all cleaning is completed, check whether there is water leakage. If there is water leakage, apply for outsourcing repair; if there is no water leakage, reinstall it (if the sealing gasket of the flange has aged, it should be replaced).
4.6 Maintenance of cooling water pump units and chilled water pump units: Refrigeration technicians should clean and maintain cooling water pump units and chilled water pump units every six months.
4.7.1 Motor maintenance:
a) Use a 500V megger to check whether the insulation resistance of the motor coil is above 0.5MΩ, otherwise it should be dried or repaired;
b) Check whether there is any blockage in the motor bearings. If so, add lubricating oil. If it still does not work after adding lubricating oil, replace the bearings with the same model and specifications;
c) Check the motor Whether the fan blades are scratched or not? If so, they should be trimmed.
4.7.2 Water pump maintenance:
a) Rotate the water pump shaft and observe whether there is any blockage, collision or jamming. If there is a bearing problem, add lubricating oil to the bearing or Replace the bearing; if there is a problem with the water pump impeller, the water pump should be dismantled and repaired;
b) Check whether the pressure packing is leaking and forming a line. If so, the pressure packing should be added (irregularly).
4.7.3 Check whether the elastic coupling is damaged. If damaged, replace the elastic rubber pad (from time to time).
4.7.4 Clean the water pump filter.
4.7.5 Tighten all fastening bolts of the water pump unit.
4.7.6 Clean the casing of the water pump unit. If the paint is peeling off or severely rusted, it should be repainted.
4.8 Refrigeration technicians should perform maintenance on the chilled water pipelines, cold air supply pipelines, and fan coil unit pipelines every six months, and check whether there are a large number of Condensation or the insulation layer is damaged. If so, the insulation layer should be redone.
4.9 Valve maintenance: Refrigeration technicians will perform maintenance on valves every six months.
4.9.1 Maintenance of control valves and regulating valves:
a) Check for leaks, if so, pressurize the packing;
b) Check the valves Whether the opening and closing is flexible, if the resistance is large, the valve stem should be filled with lubricating oil;
c) If the valve is broken or fails to open and close, the valve of the same specification should be replaced;
d ) Check whether there is leakage at the flange connection. If so, the sealing gasket should be replaced.
4.9.2 Maintenance of electromagnetic control valve and differential pressure control valve:
a) Drying filter: Check whether the drying filter is dirty or blocked or absorbs moisture. If so, replace it with the same one. Specifications of dry filter;
b) Solenoid regulating valve and differential pressure regulating valve:
——Turn on and off the power to check whether the electromagnetic regulating valve and differential pressure regulating valve operate reliably, such as If there is a problem, replace the solenoid regulating valve and differential pressure regulating valve of the same specification;
——Add lubricating oil to the valve stem between the differential pressure regulating valves. If there is leakage at the pressure packing, pressurize the packing.
4.10 Maintenance of the detection and control parts: Refrigeration technicians will perform maintenance on the detection and control parts every six months.
4.10.1 Maintenance of detection devices (thermometers, pressure gauges, sensors):
a) Thermometers and pressure gauges with unclear readings should be replaced;
b) Thermometers and pressure gauges must be submitted for inspection before they pass the test before they can be used again;
c) Check whether the sensor parameters are normal and conduct simulation experiments. Unqualified sensors should be replaced;
d) Check whether there is leakage in the area where the detector is installed. If there is leakage, replace the sealing gasket.
4.10.2 Maintenance of the control part:
a) Clean dust and dirt inside and outside the control cabinet;
b) Check and tighten all terminals , seriously ablated terminals should be replaced;
c) AC contactor maintenance:
——Remove carbides and metal particles in the arc extinguishing cover;
——Clean the dirt on and around the contact surface (but do not file the contacts). If the contact is severely ablated, replace the AC contactor of the same specification;
——Cleaning iron Dust and dirt on the core;
——Tighten all fastening bolts.
d) Thermal relay maintenance:
——Check whether there are any signs of overheating or burns at the wire joints of the thermal relay. If so, they should be repaired. If they do not meet the requirements after treatment, should be replaced;
——Check whether the insulation cover on the thermal relay is complete, if damaged, it should be replaced.
e) Maintenance of automatic air inlet:
——Use a 500V megger to measure the insulation resistance should not be less than 0.5MΩ, otherwise it should be dried;
——Remove carbides or metal particles in the arc extinguishing cover. If the arc extinguishing cover is damaged, replace it;
——Remove small metal particles on the surface of the contact (do not file).
f) Maintenance of signal lights and indicating instruments:
——Check whether each signal light is normal. If it does not light up, replace it with a small light bulb of the same specification;
——Check whether the indications of each indicating instrument are correct. If the deviation is large, make appropriate adjustments. If the deviation is still large after adjustment, replace it.
g) Maintenance of intermediate relays and signal relays: Conduct simulation experiments on the intermediate relay and signal relay to check whether their actions are reliable and whether the output signal is normal. Otherwise, the intermediate relay and signal relay of the same model should be replaced. Signal relay;
h) If there is a problem with the PC central processor or printed circuit board.
4.11 Compressor maintenance: Check and maintain the compressor once a year.
4.11.1 Check the compressor oil level and oil color. If the oil level is lower than 1/2 of the sight glass, the cause of the oil leakage should be identified and the fault should be eliminated before filling with lubricating oil; if the oil has changed color, the lubricating oil should be completely replaced.
4.11.2 Check whether there is air in the refrigeration system. If there is, the air should be discharged.
4.11.3 Specifically check the following parameters of the compressor:
a) Compressor motor insulation resistance (normally above 0.5MΩ);
b) Compressor operation Current (normal is rated value, three-phase is basically balanced);
c) Compressor oil pressure (normal 10~15kgf/Cm2);
d) Compressor shell temperature (normal Below 85℃);
e) Suction pressure (normal value 4.9~5.4kgf/cm2);
f) Discharge pressure (normal value 12.5kgf/cm2);
g) Check whether the compressor has abnormal noise or vibration;
h) Check whether the compressor has abnormal smell.
Through the above inspections, it is comprehensively determined whether the compressor is faulty. If so, the compressor should be replaced (outsourced maintenance).
4.11.4 Tighten all fasteners and clean the compressor.
4.14 When the central air conditioner needs to be decommissioned due to maintenance or other reasons, the head of the equipment department should fill in the "Decommissioning Application Form", and after approval by the manager in charge, notify the company affairs department, and the company ** *The affairs department will notify the relevant business departments one week in advance.