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All the reasons and solutions of air conditioning is not cooling

1. The fault code contains the faulty content

For the meaning of the code do not know it does not matter, but for the code contains the contents of the universal fault must be mastered, the following list of air-conditioning fault code meaning, only meaning that no matter what code.

1. The sensor is shorted
The reasons for the open circuit of the sensor are broken, the plug is poorly connected, the socket is desoldering, etc. The reason for the short circuit is that the resistance becomes smaller than 200Ω, the circuit board has leakage or the leakage of the component.
High pressure, low pressure protection
Four – way valve conversion fault protection;
Three – phase phase sequence and phase – absence protection.
Overvoltage and undervoltage, the normal voltage range is 10% (200-240V).

2. Run the detection parameters
Refrigeration room heat transfer coil temperature is too high, cold protection;
Heating chamber heat transfer coil temperature is too low, overheating protection;
Compressor thermal overload switch action;
Outdoor current protection (including galvanic coil open circuit, short circuit, wire did not pass, etc.);
Detection of fan speed circuit damage, motor failure (internal fan, external fan stop, abnormal operation protection);
Indoor and outdoor communication failure, indoor board communication failure;

Of course, not every air conditioner has the above fault display, but when the air conditioning failure, we should know that there may be many factors above, in order to facilitate our troubleshooting.

Second, maintenance analysis and troubleshooting

So many of the above fault display code, do not know the meaning of the case, do not have to start it? According to maintenance experience and fault characteristics, but also can be quickly resolved.

1. High failure rate characteristics

According to the maintenance of air conditioning summary, found the following several cases is the main reason for air conditioning failure, in the actual maintenance process, the highest failure rate.

(1) indoor heat exchanger coil temperature sensor damage rate is highest, even if not bad, it detected by the failure rate is relatively high. So if you think the sensor may be the case, you may wish to check and replace.

(2) lack of fluoride is also a common fault in the air conditioning work for some time after the protection of the case, the first should be checked whether the cooling effect is good, it is necessary to carry out air conditioning three pressure measurement, cooling pressure and low pressure Pressure measurement, heating to balance the pressure and high pressure measurement.

(3) power supply voltage problem is also very prominent, especially the peak power. For the three-phase air conditioning can not start the first check object is phase sequence.

Air conditioning power supply inspection is the focus of the contact (air conditioning and total power switch) whether the ignition ablation, poor contact, the total power switch internal contact is good, resistance to current capacity is met, the total power cord is too long too thin, the voltage is less than 200V The The zero line and the ground is mixed, three-phase phase line and the zero line is mixed.

(4) high pressure protection, especially in the summer when the cooling room is not good heat. Compressor overload protection, common in high temperature and peak hours in summer.

(5) remote control receiver and display board circuit is also a multiple fault, voltage measurement and replacement for the best choice.

(6) For places where the environment is poor. To check the internal and external connections, indoor lines whether the mouse bite the place, which is more frequent fault, as well as the circuit board and buttons are damp.

(7) between the inside and outside the machine has a long line and the line of the joints are also fault prone point, the requirements of the wire connector is welded with waterproof insulation tape, and some installers are just twisted together with a pack of ordinary tape thing.

(8) air-conditioning connectors are poor contact is one of the causes of multiple failures.

2. Judgment of fault protection time

According to the time of air conditioning protection failure analysis is also a good way, the basic protection of air conditioning can be divided into power can not start protection, protection within a short time after the start, 10-15 minutes after the start of protection, variable time protection and other four categories.

(1) power can not start protection, including power even if not activated will protect the situation. This situation is mainly caused by the sensor open circuit, short circuit, power anomalies, CPU peripheral circuit abnormalities, communication failure, circuit board failure and so on.

(2) within a short time after the start of protection is mainly inside and outside the fan rotation is abnormal or not turn, Hall speed component damage, galvanic coil circuit failure, so that the CPU can not detect the normal working voltage signal. Compressor leakage, stall, short circuit, undervoltage start and so on.

(3) 10-15 minutes after the start of protection, mainly to check whether the normal refrigeration system, the cooling effect is normal, whether the lack of fluoride, or indoor heat exchanger coil temperature sensor is deterioration from the normal resistance.

(4) from time to time to protect the main cold and cold, heating overheating, working pressure, working current, the compressor is running in low voltage, air conditioning power cord contact problems, poor outdoor heat exchange, overvoltage module overcurrent.

3. Troubleshoot the inside and outside of the circuit board

Familiar with the circuit structure, first clear the control board inside and outside the circuit, external detection, external control, etc., to distinguish between the internal and external causes of failure to determine whether the circuit control failure or refrigeration system failure – to determine the indoor or outdoor failure.

(1) analysis circuit. Analyze the role of each wire or plug connected to the circuit board, find out the external lines used to detect air conditioning performance, and check if there are significant open and short faults on these lines.

(2) to determine the inside and outside the board failure. Circuit board circuit is basically normal, can be roughly judged circuit board failure. Fault detection can be performed by voltage detection and function commissioning.

Like to be able to receive remote control beep, the normal operation of the fan function, heating operation of the four-way valve can work to determine the basic control panel normal.

Power on the remote control does not receive, buzzing exception, do not operate their own work, work program disorders can determine the circuit board itself is faulty, or +12 V and +5 V power supply abnormalities, the public power circuit circuit.
I do not know the meaning of the code in the first Jane Fan Fan, the first easy after the first outside the routine inspection means, the key points of the pressure, voltage, current, resistance measurement, in order to achieve the purpose of rapid troubleshooting.

(1) machine routine inspection:
Observe the relationship between protection and start-up time for fault diagnosis.
Remote control can work, receive the first three points of the voltage is normal.
Indoor, external fan is running.
Pre-protection signs.
The sensor has no obvious open circuit, short circuit.
Indoor machine filter is dirty, outdoor machine is poor heat, poor ventilation.
The user power check includes phase sequence, voltage level, power wire diameter, contact and so on.
220V voltage, working current measurement.
Whether the outdoor unit four-way valve heating action, whether the compressor and the external fan does not work.
Unscrew the external wiring board to measure 220V, communication voltage, contact is bad.
Unscrew the outer cover to check the compressor capacity, fan capacitance.
Inverter air conditioner but also to measure the external machine PN voltage, frequency conversion module output voltage.

(2) routine inspection of the circuit board:
Fuse, varistor is burned.
+ 12V, + 5V is not normal when the filter capacitor, transformer coil off, load and no-load voltage, CPU power supply, drive integrated circuit and transistor voltage.
Reset voltage, CPU terminal whether Weld, desoldering, 4M crystal replacement.
Remote control receiver, display circuit measurement and replacement.
The relay, especially the power relay terminal is desoldering, the plug is bad contact.
CPU input signal, the output signal voltage, drive process measurement.

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Circuit board on the front and back whether there is flooding, corrosion, dirt, galvanic coil of the wire through the skeleton, the thread with or without loose, off.

(3) refrigeration system routine inspection:

Refrigeration system Balanced pressure, low pressure or high pressure measurement.

Current measurement, observe the gas, liquid valve condensation frost situation, the opening degree of the two valves. Check the wall hole pipe bending, inside and outside between whether the pipeline and wire.

(1) If the three-phase control must first phase sequence.

(2) plug and boot no sound or instructions, display, or abnormal sound, be sure to check the power supply. Including the user power, the power supply, and some power supply is provided by the outdoor to the room, outdoor transformers and fuses.

(3) CPU operating conditions check. CPU operating conditions include + 5V, reset (resistance 4.8V, integrated 3V), replace the crystal, the external circuit with or without leakage or short circuit.

(4) plugged in the sound, remote no sound, remote control or receiver head failure.

(5) plug in, remote control has a sound, a few seconds to protect, check the sensor open circuit, short circuit, pressure switch, temperature switch and other open circuit.

6. Auxiliary method check

(1) use the priority characteristics of the fault display to infer the faulty components

Air conditioning fault detection and display are priority, the maintenance process can use this feature to exclude non-fault location, analysis of the fault location. For example, repair a “beautiful” Guiji, there E3 display, respectively, plug the three sensors, the display changes, when the pull room temperature sensor, the letter unchanged, to determine its damage, open the baffle is broken reasons The

(2) use the debugging function to determine the sensor failure

Debugging functions are generally automatic and forced to cool. Automatic function can be used to determine the indoor temperature sensor failure, the use of forced cooling can determine whether the sensor failure, because the forced cooling conditions only controlled compressor temperature limit, the other temperature does not work.

(3) cabinet panel button or hook button to ensure that no leakage.

Air conditioning button due to work in a humid environment or the use of wear and tear, will lead to sticky adhesive or leakage, causing CPU protection, for difficult problems can be hot iron terminal or welding test machine.

In summary, the maintenance process we have to be specific to the phenomenon of a reasonable analysis of reasonable, and then decide what means to check what parts, rather than the above said one of the order of a check.

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