High exhaust temperature
A. False high temperature
1) The temperature sensor is broken, or the wiring of the temperature sensor is wrong. At present, the temperature sensor used by our company is PT100. Pay attention to the difference between positive and negative when wiring. The two red wires are negative in parallel and connected to the signed end of the circuit diagram. The other white wire is connected directly.
2) Check whether there is a broken wire fault in the middle of the temperature sensor, or whether there is a problem with PT100. Under the standard condition (20 ℃), use an ohmmeter to measure the resistance of Pt100 about 100 Ω. If it is too large or too small, it means it is broken.
B. Really high temperature
1) High ambient temperature: the designed ambient temperature of comps air compressor shall not exceed 40 ℃. If the surrounding environment is high, there will be high exhaust temperature. At the same time, pay attention to whether the air inlet of the chassis is blocked, whether the hot air of the radiator can be discharged smoothly, or whether the hot air returns to the air inlet of the chassis.
2) Whether the screw oil level is too low, which causes the main oil return pipe of the oil and gas drum not to return oil fully. If the temperature drops significantly after adding some screw oil, this is the problem.
3) Whether the fan reverses or the radiator air duct is blocked seriously. The blockage of the radiator air duct is a common problem. When purging the radiator, the air duct must be blown through. The judgment method is: you can see the other side from one side of the radiator through the air duct fins.
4) Whether the oil filter has not been replaced for a long time, resulting in blockage, which affects the reduction of screw oil injection into the machine head and leads to high temperature. Solution: replace the oil filter. If there is no oil filter on site, poke several short-circuit holes in the old oil filter for test verification.
5) Whether the whole pipeline and components on the pipeline from the main oil return pipe of the oil and gas barrel to the main oil injection port of the machine head are blocked? For example, the radiator oil passage is easy to be blocked after coking, and the main method can only be removed one by one for treatment and inspection.
6) Coking of screw oil (long-term non maintenance, mixing of screw oil and long-term high-temperature screw oil hydride evaporation) blocks the main oil return pipeline or the radiator oil passage. If screw oil is mixed, the temperature is high during loading.
7) The failure of the temperature control valve is generally caused by the damage of the paraffin package of the temperature control valve or the jamming of the valve core of the temperature control valve, resulting in the failure of the valve core to open normally, resulting in the failure of comprehensive large circulation of screw oil. The treatment method is to temporarily pad the temperature control valve core, and then replace the valve core for the customer.
8) If the oil return valve of the compressor with the oil stop valve p920k fails, the oil return valve of the compressor with the oil stop valve p920k will also fail.
9) Another high temperature phenomenon is that the starting temperature increases sharply, and the temperature is normal after the pressure is established. One reason is that the oil is relatively thick in winter and the pressure is not enough to quickly press the oil into the machine head when starting up. After starting up for several times, the screw oil temperature rises and the fluidity is good, and the fault phenomenon disappears. The solution is to start the unit by multi-point action to reduce the viscosity of the screw oil, but pay attention that improper operation will lock the machine head. It is recommended to add screw oil into the machine head in advance. If the viscosity of the inching screw oil decreases or it is high temperature for many times, check whether the discharge capacity of the relief valve is too large, so that the pressure cannot be established and the temperature increases. The discharge size should be reasonable. If the discharge is too large, the pressure cannot be established quickly during startup, and the temperature will be high. If the discharge is too small, the pressure of the oil and gas barrel is too high during shutdown, and the air inlet will inject oil.
10) Some heads are designed at a high position. If there is no oil stop valve and exhaust check valve on the head, the oil in the head will be harped into the oil and gas barrel or pipeline after the machine is shut down for a period of time, resulting in a lack of oil in the head, and the temperature will rise too fast during startup.