When using the air conditioner, I found that the air conditioner doesn't make heat. How should I solve it? I suggest that you first understand the good reasons, and then further find solutions. Let's have a look.
Cross flow of four-way valve
Heat pump air conditioner switches the state of refrigeration and heating through four-way valve. During refrigeration, the outdoor heat exchanger is used as the condenser, and the indoor heat exchanger is used as the evaporator to absorb heat; When heating, the outdoor heat exchanger is used as the evaporator, and the indoor heat exchanger is used as the condenser to release heat. If the four-way valve is crossed, part of the refrigerant that should have participated in the heat exchange will directly return to the air return pipe from the outlet pipe of the compressor at the four-way valve, resulting in the reduction of refrigerant participating in the heat exchange and the reduction of heat exchange efficiency, resulting in insufficient heating.
The external performance is mainly that the high and low pressure is unstable, and the cold and heat of the touch pipeline (connected to the two heat pipes and two cold pipes of the four-way valve) are uneven; Some faults are similar to insufficient refrigerant or insufficient refrigeration and heating, but the pressure at the high-pressure side is normal through detection.
Air leakage of one-way valve (also known as check valve)
The refrigeration cycle system of heat pump air conditioner is shown in the attached figure. Due to the great difference between refrigeration and heating states of heat pump air conditioner, it is often unreliable to switch the flow direction of refrigerant only by electromagnetic directional valve. Therefore, one-way valve is often used in heat pump air conditioner to switch the flow direction of refrigerant safely and effectively. In the refrigeration cycle, the difference between high and low pressure is small, the throttling element is the main capillary, and the auxiliary capillary is short circuited by the check valve; During the heating cycle, the one-way valve in parallel with the auxiliary capillary does not conduct, and the throttling element is connected in series with the main capillary and the auxiliary capillary, which can increase the resistance of the throttling element, that is, increase the high and low pressure difference of the refrigeration system, reduce the temperature of the outdoor heat exchanger, and obtain more heat from the outside, so as to achieve the purpose of heating.
When the one-way valve leaks, the high and low pressure differential of the refrigeration system decreases, the temperature of the outdoor heat exchanger increases, and the heat obtained from the outside decreases, resulting in insufficient heating. In case of normal refrigeration and insufficient heating capacity of the air conditioner, by detecting the pressure during the operation of the system, it will be found that the pressure at the low pressure side increases and the differential pressure between high and low pressure decreases.
Defrosting controller failure
The evaporator of the heat pump type air conditioner in the heating state is located in the outdoor unit. For the heat pump type air conditioner with the heat shock defrosting device, if the defrosting controller fails, so that the air conditioner cannot be transferred to the defrosting operation state in time, the evaporator frosting phenomenon will occur during the heat pump heating, which will affect the heat exchange efficiency of the air conditioner heating, resulting in insufficient heating and even shutdown. At this time, the following phenomena should be observed: the defrosting temperature sensing device is misplaced, the contact is stuck or has poor contact, the fan impeller slips or the air duct is blocked, and the solenoid valve or starting relay fails.
Failure of auxiliary electric heating function
At present, PTC electric auxiliary heating technology is widely used in heat pump assisted electric heating air conditioning. PTC electric auxiliary heating technology can quickly heat under ultra-low temperature conditions, with strong effectiveness, safety and reliability, and can be used for a long time. If the electric auxiliary heating control circuit or electric auxiliary heating equipment fails and cannot work normally, it will lead to insufficient heating capacity of the air conditioner when the ambient temperature is relatively low, and even no heating at all when the environment is bad. For the heat pump auxiliary electric heating air conditioner, if the ambient temperature is high (above 5 ℃) and the heating is normal, but the ambient temperature is low (below 0 ℃) and the heating is insufficient or does not heat, it should be suspected that the electric auxiliary heating control circuit or electric auxiliary heating equipment is faulty, and these two parts should be checked emphatically during maintenance.
Improper use
There is too much dust on the air filter, and the air vents of internal and external machines are blocked by foreign matters. The function of the filter screen is to absorb the dust in the air. If too much dust is accumulated and not cleaned in time, it will block the air circulation, resulting in the reduction of the air volume at the air outlet, so that the heating capacity in the machine cannot be brought out in time by the flowing air, resulting in insufficient heating capacity. This is not a fault. It belongs to the maintenance problem of the air conditioner. It can be restored to normal by removing the air filter screen regularly for cleaning, Generally, it is appropriate to clean the filter screen once every half a month (do not use hot water above 40 ℃ during cleaning, and do not use washing powder, detergent, gasoline, banana water, etc. to avoid deformation of the filter screen and drying with open fire); The dust and dirt of evaporator and condenser are too thick, which will reduce the heat exchange effect, reduce the heating capacity and increase the power consumption; The heating temperature is set too low; The door crack and wall hole of the air-conditioned room are not blocked, or the windows are opened frequently, resulting in indoor heat loss.
Environmental factors
Cold and warm air conditioners are divided into three types: heat pump type, heat pump assisted electric heating type and electric heating type. Under the condition of equal heating capacity, the power consumption of the first two types is about half less than that of the third type. Considering the power supply capacity and power consumption cost, today's families generally choose the first two types of air conditioners (but attention should be paid to their service conditions. The first two types are only applicable to the environment above minus 5 ℃, which is obviously not applicable to the northern region). For heat pump air conditioner, the ambient temperature is too low during heating, and the energy efficiency ratio of air conditioner is also reduced. In colder winter, the heating effect is not ideal, which is a normal phenomenon.
For the heat pump air conditioner without automatic defrosting, the minimum ambient temperature used is 5 ℃ above zero. If it is lower than this temperature, there is no heating or the effect is very poor. This is because the frost on the external heat exchanger blocks the air flow and can no longer absorb heat from the outside; For the heat pump air conditioner with automatic defrosting, the minimum ambient temperature used is also minus 5 ℃, below which it can not heat effectively.
In addition to environmental factors and improper use by the owner, there is another important reason why the air conditioner only cools without heating, which is the failure of the refrigeration cycle system and control system, which is mainly reflected in the following points:
Insufficient refrigerant
Due to the leakage of the refrigeration system, there is insufficient refrigerant participating in the thermal cycle in the system, resulting in the decline of heat exchange efficiency, resulting in insufficient heating. In case of such faults, the heating capacity and refrigerating capacity of the system will be insufficient. At this time, connect the pressure gauge to measure the pressure of the system, and it will be found that the pressure is significantly lower than that under normal conditions. Then check the pipeline, and obvious oil stains will be found at the serious leakage point, while for the slight leakage point, the leakage shall be detected by electronic leak detector.
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