In the cold winter months, neglecting maintenance can lead to compressor malfunctions. During winter, due to long periods of inactivity and lack of antifreeze protection, incidents such as cooler cracking and body failure upon startup are not uncommon.
Here are some precautionary measures for oil-injected and oil-free compressors during winter shutdown and startup. Be sure to save and share them.
Oil-Injected Compressors:
1. Before starting the compressor, ensure the oil temperature is not below +2°C. If the temperature is too low, use heating devices to warm the oil tank and main unit areas.
2. Check that the oil level is at a normal position and all condensate drain outlets are closed (open them during long periods of inactivity). For water-cooled units, also check if the cooling water drain valve is closed (open it during long periods of inactivity).
3. After disconnecting the power supply, manually rotate the main unit coupling by hand; it should rotate freely. If rotation is difficult, do not start the compressor blindly. Check for any faults in the body or motor and whether the lubricant has thickened or failed. Only after resolving these issues should you start the compressor.
4. For machines that have been idle for a long time or have used oil filters for an extended period, it is recommended to replace the oil filter before startup to prevent insufficient oil supply due to thickened oil reducing filter penetration capacity at startup, which can cause instant overheating and body failure.
5. After these checks, perform a brief test run on the first startup to check operation and sound during startup. If there is a sudden temperature change, stop immediately and inspect the machine; do not frequently restart it. Add a suitable amount of coolant if necessary.
6. If a heat recovery system is installed, close the oil circuit valves of the system and slowly open them after normal operation of the unit is achieved.
7. For two-stage compressors, especially high-power models, after a period of inactivity, add some lubricant at the intake and briefly start 2-3 times; fully open the oil injection control valve from the oil tank to the body at startup. If exhaust temperature is too low after stable operation, adjust customer cooling water valve inflow to control temperature; adjust oil injection valve to achieve suitable exhaust temperature if necessary.
8. Pay attention to exhaust temperature in variable frequency compressors during winter to avoid excessively low temperatures (mainly due to prolonged low-frequency operation). Adjust cooling water valve opening according to exhaust temperature; replace with high-temperature thermal control valve core if necessary to avoid oil emulsification.
Oil-Free Compressors:
For oil-free compressors like ZW and SWT models in winter, especially during long periods of inactivity and startup, pay attention to the following points. Make sure all service personnel and customer equipment personnel are notified!
1. During downtime, if possible, provide some form of heating for the compressor; if not possible, cover the compressor with plastic sheeting or other coverings to protect it from wind and snow erosion.
2. While operating, compressors generate high temperatures; after stopping in cold weather conditions, significant condensation forms in pipes which can lead to blockages or freezing and cracking of exhaust pipes if not drained promptly in winter's cold weather conditions—ensure all gas is vented out after stopping along with draining sewage/water from pipes promptly after cooling down.
3. For SWT and ZW water-cooled models: empty cooling water network; open cooler drain/sewage valves on ZW machines; open all intermediate/aftercooler drain/sewage valves on SWT machines—similarly open cooler sewage valves on air-cooled models too for removing liquid inside coolers effectively.
4. After stopping ZW machines during holidays: turn off power supply; open all drain/sewage valves; manually spin coupling quickly in indicated direction by hand—this helps remove water inside body efficiently post-holiday shutdowns effectively too!
5.Before first startup post-holidays: check all previously opened valves thoroughly beforehand—manually rotate coupling on ZW machines before initial startup (ensure no ice blocks formed inside body); proceed only if normal rotation observed—same applies for SWT machines too—manual checking required prior initial startups here as well!
6.For SWT machines: pay attention during instant startups due environmental low temperatures affecting lubricant fluidity causing potential damage—raise ambient temperature before starting if possible—closely monitor oil pressure during startup moments (SWT gears rotate very fast—delayed lubrication may damage gears).
7.Avoid using automatic operation mode under extreme cold environments for air compressors!