Is your screw-type air compressor experiencing issues such as excessively high discharge temperature, oil backflow, or insufficient air output?
Under normal operating conditions, if the compressor’s temperature sensor switch or temperature display device fails, the protective device may malfunction, potentially leading to degradation of the lubricating oil.
Time:
2026-05-29
l High exhaust temperature
Under normal operating conditions, a failure of the compressor’s temperature sensor switch or temperature display device may prevent the protective device from functioning properly, potentially leading to lubricant degradation.
(1) Oil separator malfunction
The oil separator is used to separate compressed air from lubricating oil within the compressor unit. If it fails:
(a) If the oil separator becomes clogged, it will increase the compressor’s operating resistance and raise energy consumption, ultimately leading to excessive unit temperatures. Clogging can be addressed by cleaning; in severe cases, the oil separator must be replaced.
(b) If the oil separator develops a puncture or becomes damaged, it will lead to increased oil consumption and elevated temperatures, which in turn will raise the exhaust gas temperature. In such cases, the oil separator should be replaced immediately.
(2) Oil filter blockage
The oil filter removes metal particles and impurities from the compressor’s dedicated lubricating oil, ensuring that only clean oil enters the compressor head and thereby safeguarding the equipment’s safe operation. If the filter becomes clogged, it may cause excessive discharge temperatures and shorten the service life of both the oil and the oil separator. If normal performance cannot be restored after cleaning, replacement is recommended without delay.
(3) Pressure valve jamming
The minimum pressure valve ensures proper lubrication of all compressor components during startup, maintains oil pressure at its lowest allowable level for optimal oil–air separation, and prevents backflow of compressed air when the unit is unloaded or shut down. If the valve becomes stuck, fails to open, or does not fully open, it can cause excessive oil‑tank pressure, increased energy losses, and elevated discharge temperatures. This issue can be resolved by inspection or replacement.
(4) Oil shut-off valve stuck
The oil shut-off valve in the unit plays a critical role during operation by connecting the oil circuit and ensuring smooth circulation of lubricating oil. Consequently, if the oil shut-off valve malfunctions—failing to open or not fully opening—it will prevent lubricating oil from reaching the compressor head, leading to insufficient oil return, elevated unit temperatures, and a corresponding rise in discharge temperature.
Oil mist injection during unit shutdown
(1) The intake valve failed to close.
If the intake valve fails to open, it will affect the compressor’s gas output. In the event of a malfunction, the relevant components of the intake valve must be inspected or replaced.
(2) Malfunction of the relief valve
When the minimum pressure valve fails to close, the compressor cannot properly load, causing gas to flow back into the oil tank during shutdown and resulting in oil carryover.
(3) Check valve (one-way valve) malfunction
The check valve prevents oil from flowing back into the pump head during shutdown, thereby avoiding oil splashing. If the check valve does not seal properly or fails to close, its protective function will be compromised, resulting in oil splashing. Upon detecting a malfunction, it should be replaced immediately.
(4) Fuel shutoff valve stuck
The oil shut-off valve ensures that the oil circuit is isolated when the unit is stopped. If it fails to close, oil injection may occur during shutdown. It is recommended to inspect and maintain the oil shut-off valve promptly.
l Insufficient gas production during unit operation
(1) Air filter element clogged
A clogged air filter element can result in insufficient exhaust flow from the unit. In such cases, remove the air filter element, clean it with compressed air, or replace it outright.
(2) Sticking of the minimum pressure valve
When the minimum pressure valve fails to open or does not fully open, gas production will decrease significantly. This issue can be resolved by inspection, maintenance, or replacement of the relevant components.
(3) The intake valve is not fully open.
If the intake valve fails to open or does not fully open, the compressor will be unable to produce gas normally. It is recommended to clear any blockages in the control air circuit, inspect and maintain the loading solenoid valve, check for air leaks in the control air lines, lubricate the control cylinder and its connecting‑rod mechanism, and verify that the butterfly valve is fully open. For positive‑displacement intake valves, assess the piston’s sealing performance and the condition of the spring; if necessary, replace the piston, spring, and seals, or consider replacing the entire intake valve assembly.
(4) Load solenoid valve malfunction
If the solenoid valve fails to operate properly, it will directly affect the compressor’s gas production rate and trigger overcurrent during operation, ultimately leading to motor overload.
Regular and meticulous maintenance is essential for the proper operation of screw-type air compressors. If you have any questions, please feel free to leave a message or get in touch.
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