The plate-fin surface of the evaporator is frosted, and the frost temperature of the evaporator is less than 0°C. The frost speed is related to the ambient temperature and temperature. There are two types of surface blooming on evaporators:
(1) The frost from the evaporator comes out.
Over time, the entire evaporator surface is covered. This condition is caused by too much liquid supply of the volatile agent (capillary system response speaks for itself). For the entire refrigeration system of the home air conditioner, it may be caused by problems with the air return system and the control system:
a. The gas-to-air filter is blocked by dust, the surface of the propeller of the evaporator is blocked, the airfield and electrical tolerance may be small, the fan motor does not rotate, and the speed is relatively slow, etc., thereby reducing the load of the heat exchanger on the evaporator .
b. The ambient temperature is relatively low or the gas-to-air temperature sensor has long-term resistance. In the home air conditioner, if the control system has anti-freeze protection function, after the refrigeration system has been running for a period of time, when the temperature of the evaporator tray is accurately measured by the control system within 0°C, the control panel will automatically withdraw from the refrigeration compressor and outdoor The fan, the fan in the room, the fan in the room is running at high speed.
c. Some central air conditioners have continuous operation function. When the continuous operation function formula is turned on, the operation of the refrigeration system will not be controlled by the temperature sensor, and the surface of the evaporator will be placed in the ear behind the applicator. Just turn off the continuous operation function. In the maintenance stage, first check the wing of the evaporator, the fan system, the control board to return the air temperature during operation, the hard disk temperature sensor and the ambient temperature.
(2) Another phenomenon is that after storing the capillary it gradually frosts.
Over time, the channel surfaces of the evaporator were heavily frosted, and most surfaces of the evaporator were free of dew. This phenomenon is manifested by insufficient liquid supply in the refrigeration system. For the entire refrigeration system of a residential central air conditioner, there may be a semi-covered system in the system. Does the system have a leak or drop system:
a. The temperature of the cooler is very high, the current flow is high, and part of the evaporator is frosted. Most of them are half-blocked in the throwing system. Common fault areas The previous filter of the capillary is dirty, or the indoor and outdoor connecting liquid pipes (pipes) are flattened to cause primary and secondary throwing.
b. The temperature of the cooler is not too high, the current flow is not large, and the channel of the evaporator is cold and not refrigerated, which may be due to the leakage point of the refrigeration system pipeline. Common faulty parts include system piping, butt welds, socket signal receivers, valve cores, check valves, and especially oil-contaminated parts in system piping. The control system of the household central air conditioner should have the function of system level maintenance.