Six questions about air conditioning This is what novices really need!

Six questions about air conditioning This is what novices really need!

1. Even though the heat pump air conditioner has automatic defrosting, why the heating effect below -5℃ is not good?

　　 Here are the operating conditions of the air-conditioner: single cooling type 18-43℃, electric heating type ≤43℃, heat pump type －5－43℃, heat pump auxiliary electric heating type －5－43℃. Because household air conditioners all use condensers, their maximum operating ambient temperature should not exceed 43°C. If it exceeds, the condenser temperature will be too high and the compressor will automatically stop due to overload. When used in winter, in addition to the electric heating type air conditioner, which has no limit on the minimum ambient temperature, the heat pump type and the heat pump auxiliary electric heating type are restricted, and the temperature shall not be lower than -5°C. The ones without automatic defrosting can only be used at +5°C or higher.

The reason why the heat pump air conditioner cannot be used below -5°C is that the external environment temperature is too low, and the temperature difference between the outdoor air temperature and the outdoor heat exchanger (evaporator when the heat pump is running) is very small or there is no temperature difference. The refrigerant can not absorb (or absorb very little) heat from the outside, so the heat "pumped" into the room as a heat pump is also very small, and there is no heating effect. It can be seen that heat pump type air conditioners are not suitable for heating in northern my country (referring to the north of the Yellow River).

　　 2. How to estimate the power consumption of the air conditioner? Why does the electric heating type cost electricity?

　　 In summer cooling conditions, when the cooling capacity and use conditions are the same, the power consumption of single-cooling, heat pump cooling and heating, heat pump auxiliary electric and cooling and heating (electric heating) air conditioners are the same. Its electric power can be calculated by the formula: Ne=Q/EER (W)

　　 In the formula: Ne---the electric power of the air conditioner in summer, W; Q----cooling of the air conditioner, W; EER----the coefficient of performance (coefficient of performance), generally EER=3

　　 For example: the cooling capacity of Japan's Sharp 1-hp wall-mounted air conditioner is 2640W, and the electric power Ne=2640/3≈880W. In the cooling and heating conditions in winter, the heat pump cold and heating air conditioner relies on the heat pump to run heating, which has high heating efficiency and low electricity consumption, which is similar to the cooling conditions. The heating and cooling (electric heating) air conditioners rely on electric heaters for heating. 1000W of heating requires 1000W of electricity. Therefore, an air conditioner with a heating capacity of 2600W uses 2600W in winter, which is 3% of that in summer. Times.

　　 Heat pump auxiliary electric heating type air conditioner uses both electric heating and heat pump auxiliary heating under heating conditions. The heating efficiency is high, and the electric power is between the heat pump type and the electric heating type. Therefore, when users choose cold and hot air conditioners, they must consider the power consumption in winter. From the perspective of saving electricity, it is better to choose heat pump cold and heat. However, it should be noted that there are two types of heat pump air conditioners; the other type There is no automatic deicing (frost) function and can only be used when the temperature is higher than 5℃. The other type has automatic deicing (frost) function and can be used in an environment above -5 ℃. The disadvantage of the heat pump hot and cold air conditioner is that the four-way electromagnet directional valve used causes machine failure when the four-way electromagnetic directional valve fails. The four-way electromagnetic directional valve of the famous brand product has good working reliability. Electric heating type air conditioners rely on electric heaters to generate heat under heating conditions. According to the law of conservation of energy, 1kW of electrical energy can only be converted into 1kW of heat energy, and no more heat energy can be converted. For heat pump type air conditioners, if the coefficient of performance is 3, then 1kW of electric power is input, and 3kW of heat can be obtained. Therefore, under the same heating capacity, electric-heated air conditioners consume electricity. Users should note that if you buy an electric-heated air conditioner, the electricity consumption is estimated using the electricity consumption data under heating conditions, and the electricity consumption data under cooling conditions cannot be used, otherwise it will be too small.

Six questions about air conditioning: This is what novices really need!

　　 3. What is the reason why the air conditioner cannot start up? How to deal with it?

　　 (1) Cause analysis

　　 1. The fuse in the dedicated circuit of the air conditioner is blown, or the power switch is in poor contact, or the power supply is out of phase. At present, many users use one power supply in combination, and the power supply is abnormal due to abnormal operation of other electrical appliances.

　　 2. The power supply used by the air conditioner is too low. When the voltage is lower than 10% of the single-phase normal voltage (220V), that is, 198V or less, the refrigeration compressor in the air conditioner will be difficult to start.

3. The dial button on the temperature controller is not dialed to the proper position, such as dialed to a higher position, when the power is connected, the temperature in the air-conditioned room has not reached the upper limit of the set temperature (the temperature at the starting point ), the compressor cannot be started.

　　 4. The high pressure relay is activated. If the condensing pressure is too high, the high pressure relay will be activated to stop the compressor.

　　 5. The low pressure relay is activated. For example, if the refrigerant is insufficient in the refrigeration system, the suction pressure of the compressor is too low, and the low pressure relay is activated to stop the compressor.

　　 6. When the current of the compressor or fan motor is too large, the overload protection relay is activated to cut off the power supply.

　　 (two) elimination method

　　 1. First check the reasons for the blown fuses inside and outside the air conditioner, and take measures to prevent them from blowing again. They should be adjusted and repaired in time. It is recommended that families with air conditioners should set up a dedicated power supply, which can basically prevent such failures.

　　 2. If the local power supply voltage is often in a low state, a reliable power supply voltage regulator should be used. At the same time, it is recommended that households with more household appliances use a dedicated power supply.

　　 3. Set the dial button on the temperature controller to the desired position, that is, adjust the temperature according to the temperature required by the air-conditioned room.

　　 4. Check the reason for the excessively high condensing pressure and eliminate it to restore the condensing pressure to normal pressure.

　　 5. Check the cause of insufficient refrigerant in the refrigeration system, and eliminate it, so that the suction pressure is restored to normal pressure.

　　 6. Check the cause of the compressor motor and fan motor overload, and eliminate it; press the reset button of the protection relay.

　　 4. What is the reason why the compressor stops as soon as it starts?

　　 The intermittent interrupted operation of the compressor is caused by the installation location and environmental conditions, the fluctuation of the power supply voltage, the failure of the electrical components and the failure of the refrigeration system.

　　 1. Installation location and environmental conditions.

　　2. The operation of the air conditioner caused by changes in the power supply voltage and capacity should be ensured that the power supply voltage is within ±10% of the rated voltage. However, when the power supply voltage is higher or lower than the above regulations, the current will increase, the overload protector will act, and finally the compressor will stop. When such a state occurs during startup, sometimes the compressor cannot start at all. This happens when the power supply capacity is not enough (even when the voltage "V1" is normal and the starting voltage "V2" drops). At this time, it is necessary to check the voltage of the power supply circuit and the capacity of the lead-in wire.

3. The compressor running capacitor is faulty. In a single-phase room air conditioner, if the compressor running capacitor is in poor contact or open circuit (no capacitance) when the compressor is working, the output power of the compressor motor will decrease, and the current Increase, the overload protector will act and stop the compressor. Use a tester to check the power line and compressor capacity. Replace the failed capacitor.

　　4. Failure of the refrigeration system and overload protector. If the compressor stops as soon as it starts, and the installation location, environmental conditions, power supply and other factors are normal, it should be considered whether the refrigeration system and overload protector are faulty. If the compressor motor is nearly burned out due to a short circuit between layers, the current will increase, and the compressor motor will stop due to the overload protection action. Similarly, if the excitation value of the overload protector itself changes, it will show the same action as the overcurrent phenomenon. The compressor stops due to the action of the overload protector. In this case, intermittent operation will occur without exception. Because the overload protector is an automatic reset type, the compressor will automatically start after a short while. In these cases, measure whether the voltage and current are abnormal, and if necessary, overhaul the refrigeration system and overload protector. Because the resistance of the compressor motor coil is too small to use a multimeter to check the inter-layer short circuit and burnout, a Wheatstone bridge can be used.

　　 5. Why does the cooling effect decrease when the air filter and evaporator accumulate dust?

　　 When dust accumulates in the air filter, the air flow is not smooth, the heat exchange effect of the evaporator is also reduced, and the cooling efficiency decreases (in this case, the air supply temperature is quite low). When the air conditioner is used for a long time, dust is attached to the evaporator blades, which will also cause poor air circulation. Washing off the dust on the air filter and evaporator can improve the refrigeration function. It is recommended to clean it every two weeks, at least once a month. What are the basic methods for judging an air conditioner failure?

　　Under general conditions, the basic method for users to distinguish air conditioner failures is to see, listen, touch, measure, and judge. The brief description is as follows:

1. Look --- Observe the conditions of each part, whether it is a window or split air conditioner, you can observe the refrigeration system, electrical system, and ventilation system to see if the fan is operating normally, and whether the fuse is intact and whether there is Oil stains from refrigerant leakage, etc.

　　 2. Listen --- whether there is a smooth running sound of compressors, fans, etc., and whether there is a collision sound of wind blades.

　　3. Touch --- Touch the heat and cold at the air vents and the vibration of the cabinet.

　　4. Measure---Use a thermometer to measure the temperature of the air inlet and outlet, use a multimeter to measure the supply voltage, and use a megohmmeter to measure the insulation resistance of the air conditioner.

　　 5. Judgment --- Judgment and analysis, based on abnormal phenomena to synthesize, analyze the cause of the failure, and not rush into it.

　　6. ​​What is the reason why the air conditioner is supplying air but the indoor temperature cannot drop?

　　 Under normal operation of the air conditioner, the temperature difference between the supply air and the return air (indoor temperature) should be above 8°C. If it does not reach it, it means that the air conditioner’s cooling capacity is insufficient, and the reason should be investigated. The general causes may be: refrigeration load overload or too large room; inappropriate installation location, insufficient air circulation, etc.

　　 First, find out whether it is caused by the cooling load overload of the air conditioner, and try to reduce the cooling load or increase the cooling capacity of the air conditioner. Then see if the air conditioner is installed properly. If it is inappropriate, the cold wind will not blow to people's side, making people feel not cold. When the air circulation of the air conditioner is not smooth, such as a lot of dust on the evaporator, which blocks the gap between the fins, or the air filter is blocked by dust, the circulating air is reduced, and the cooling capacity of the air conditioner cannot be fully utilized .