Precautions for air cooler selection:
A: Frosting of the air cooler: When the working temperature of the air cooler is lower than zero or lower than the air dew point temperature, frost will begin to form. When the frost thickness reaches a certain level, the heat transfer coefficient of the air cooler will decrease, the thermal resistance will increase, and the wind resistance will increase. If it is large, it will affect the heat exchange of the air cooler, so defrosting should be carried out.
B: Cooler application selection: According to the temperature requirements of the cold storage, the selection of the cooling fan should be based on the following criteria. High temperature storage: choose DL series, sheet distance: 4.5mm; medium temperature storage selection: DD series, sheet spacing: 6mm; low temperature storage selection: DJ series, film distance 9mm.
Precautions for the use of air coolers:
A. Before turning on the power, first check whether the wiring of the motor and defrosting tube is loose.
B. Check whether the fan blades of the cooling fan motor collide with the net cover, and check whether the rotation direction of the fan blades is the same as the direction marked.
C. Check whether the power supply voltage is consistent with the requirements on the nameplate.
D. Check whether the drainage pipe of the air cooler is connected well, and whether there is a U-shaped pipe in the outdoor part.
E. Check whether the defrost setting time of the air cooler is reasonable.
F. When the air cooler is used for liquid refrigerant, the wet bulb temperature of the air inlet of the cooler should ensure that the cooling coil is basically free from frost and condensed water. When the cooler is stopped, the refrigerant should be drained or Always cycle to avoid freezing and cracking the copper tubing.
Precautions for installation of air cooler:
A. When installing the cooling fan: the minimum distance between the air inlet surface of the cooling fan and the wall is not less than 50 cm to ensure the circulation of air. At the same time, when storing items in the cold storage, the air cooler air duct should be reserved.
B. The connection of the air return pipe of the air cooler should be inclined to the direction of the compressor, and the angle is less than 15°C; when the condensing unit is installed above the air cooler, an oil return bend should be added to the equipment to avoid the deposition of refrigerated oil in the pipe of the air cooler and reduce heat transfer Effect.
C. Heat preservation measures should be added to the connecting pipes between the cooling fan and the condensing unit to avoid heat loss during the heat exchange process.
D. When installing the air cooler, attention should be paid to the level adjustment between the suspension feet to avoid excessive noise caused by motor vibration.
E. The cooling fan should be installed as close to the condensing unit as possible, and the pipeline should be shortened to avoid the reduction of the airflow speed.
F. When the air cooler is defrosting, the automatic temperature sensing head should be as close as possible to the top of the middle of the air cooler or the last part of the frosting, and away from the defrosting electric heater.
G. When the air cooler is installed: the return air side should be far away from the cold storage door to avoid the entry of external air to increase the load of the air cooler and increase the frosting probability of the air cooler
H. When installing the cooling fan, leave a space equal to the length of the cooling fan on the side where the defrosting electric heater is replaced, so as to facilitate maintenance and replacement of the defrosting electric heater.
I. When installing the expansion valve, be careful not to let the welding flame face the cooling fan.
J. It is not allowed to change the angle of the cooling fan connecting pipe when the cooling fan is connected to the external system.
Daily maintenance and repair of air cooler:
A. Reasons for uneven defrosting:
Check whether the distribution head of the dispenser is blocked or whether the distribution angle is defective.
Whether there is moisture in the system and there is freezing phenomenon at the distribution angle.
If there is no refrigerant accumulation in the design when the system is shut down, the refrigerant will be stagnated at the bottom of the air cooler, and these refrigerants will evaporate first when the system is started, resulting in severe frosting at the bottom of the air cooler.
When the suction surface of the air cooler is too close to the storage board, the airflow is mostly concentrated at the bottom of the exhaust pipe, which is likely to cause severe frosting.
The position of the temperature sensing head is improper, and the frost cannot be completely removed.
The cold storage is opened too frequently, the defrosting frequency is not enough, and the defrosting time is too short.
In the low-temperature system, the drain pipe is not made a U-shaped bend, which causes the outdoor air to be sucked back to the evaporator, causing uneven frosting.
Check whether the defrosting electric heater is damaged.
B. Reasons for slow cooling:
1. When the design of the refrigeration system is unreasonable, the refrigeration oil will remain in the evaporator. With the growth of time, too much oil accumulation will seriously affect the refrigeration effect, and the oil should be drained. If the evaporator has no other faults, but the frost on the evaporator tube is sparse and incomplete, it can be judged to be such a reason.
2. The goods in the cold storage are piled up too much and the load is heavy. Or the goods are placed in the air duct of the fan, which hinders the air supply of the fan.
3. The configuration of the cooling fan is too small.
4. The selection of the air cooler is wrong, resulting in too frequent defrosting; the defrosting cycle is too short or the defrosting time is too long; the temperature of the storage room is high.
5. Wrong selection of expansion valve, or improper installation and adjustment.
6. Too much or too little refrigerant charge.
7. The connecting pipe between the cooling fan and the condensing unit is too long, and the heat loss and heat load are too high.
8. When the pressure loss of the air cooler is large, consider replacing the external balance expansion valve.
9. Observe whether the motor of the air cooler is reversed; whether the inlet and outlet pipes are reversed.