The operating performance of an ammonia compressor directly determines the cooling capacity and energy efficiency of the refrigeration system. Periodic maintenance and timely repair can both extend equipment service life and effectively avoid production losses and high repair costs caused by unplanned downtime. Equipment maintenance should be systematically carried out from two dimensions—routine maintenance and troubleshooting—and integrated throughout compressor lifecycle management.
Routine maintenance covers several mandatory items. For the motor, frequently check whether foreign matter or conductive objects have entered the motor and confirm that the winding insulation is intact. Equipment housekeeping also must not be neglected: regularly clean dust adhering to the surfaces of the compressor and condenser. Excessive dust accumulation will reduce heat transfer capacity, leading to high-pressure system operation and even insufficient cooling. The oil level in the oil sump should be checked regularly; when it is below the oil level mark, replenish oil to the specified range in a timely manner. The lubricating oil used must be pre-settled and filtered to remove entrained moisture and impurities. Different compressor oil grades should be used in winter and summer to accommodate the effect of viscosity changes on lubrication at different ambient temperatures. During sealing checks, if ammonia escapes from the crankcase breather hole, it is usually caused by wear of the piston rod packing. First try tightening the packing gland nut, with each adjustment not exceeding half a turn, to avoid excessive tightening causing premature packing failure.
Troubleshooting common faults requires judgment based on operating parameters and on-site symptoms. When startup is difficult or the compressor cannot start at all, first check whether the supply voltage is too low and whether wiring connections are reliable; also check whether the discharge valve plate is damaged or leaking, causing excessive crankcase pressure. Insufficient or no oil pressure generally results from insufficient lubricating oil inventory, blocked oil lines, too little oil in the crankcase, or foaming caused by ammonia liquid ingress into the oil. Add lubricating oil as appropriate, clear the lines, and investigate the specific cause of ammonia liquid ingress. Low suction pressure usually indicates insufficient liquid supply due to insufficient opening of the liquid supply valve; the valve can be opened appropriately wider to restore liquid supply to the evaporator. Excessive discharge temperature is mostly related to insufficient oil supply from the lubrication system, low cooling water flow rate, or blockage of the gas flow passage; the lubrication and cooling systems should be checked in sequence. Abnormal vibration and noise are often caused by shaft misalignment, bearing wear, loss of dynamic balance of rotating components, or loose foundation bolts; they should be eliminated by checking alignment, replacing worn bearings, and tightening connecting bolts. Refrigerant leakage in the system is mostly caused by corrosion thinning and seal wear/aging; leak detection instruments should be used to locate leak points and replace the corresponding sealing elements. Compressor cylinder seizure is usually attributed to improper operation or long-term inadequate lubrication; fundamentally, operating procedures must be standardized and routine maintenance strengthened to avoid cumulative damage from abnormal operating conditions.
Maintenance of screw compressors has special requirements. The oil return valve at the bottom of the oil separator must be adjusted precisely to ensure that the oil level in the sight glass at the rear stage of the oil separator remains stable, thereby confirming unobstructed and appropriate oil return. The dry gas seal system is a key barrier for screw ammonia compressors to prevent high-temperature, high-pressure ammonia gas in the cylinder from leaking outward. During operation, close attention must be paid to its working condition, and seal gas pressure, flow rate, and leakage-side discharge should be checked regularly. Once abnormal fluctuations or signs of leakage are found, the compressor should be shut down immediately for inspection and handling to prevent seal failure from causing a serious accident.
Establishing a preventive maintenance plan is an important guarantee for long-term safe operation of equipment. During daily operation, check oil level, record operating parameters, and listen to operating sounds to identify incipient problems in a timely manner. Weekly, clean equipment surfaces and the surrounding environment and check sealing conditions at pipeline connections. Monthly, tighten electrical wiring terminals and test the operational reliability of safety protection devices such as oil pressure relays and high/low pressure relays. Quarterly, replace or filter lubricating oil, check valve plate wear, and measure changes in clearance volume. Annually, arrange a comprehensive overhaul, and calibrate and verify legally required measuring instruments such as safety valves and pressure gauges to ensure accurate values and sensitive operation.
The investment in equipment maintenance is far less than the cost of emergency repair after a sudden failure. By establishing a management philosophy centered on prevention and combining routine maintenance with periodic inspection and repair, the safe, efficient, and long-term operation of ammonia compressors can be maximized.
