There are two main problems when fan coil units do not refrigerate, namely, water loop and wind loop.
Wind system:
Dust nets and coils have been used for a long time without cleaning. Excessive dust blocks the air duct, which reduces the circulating air volume, thus causing the air conditioner not to cool. Dust nets and coil fins can be cleaned.
Fan motor has faults. All fan coils are centrifugal fans with low noise and adjustable speed. The faults include winding short circuit, open circuit and operation capacitance loss, which can only be measured and judged by multimeter resistance files.
The temperature controller is faulty. When the fan coil is not cooled, first check whether the temperature control switch is at the cold end and whether the position of the temperature control knob is lower than the room temperature. If all these are normal, disassemble the panel to check whether there is a power supply. If so, check whether there is electricity in the gear where the fan is located and whether the power supply of the electric valve is output.
Water system:
1. The water temperature is not low enough. That is to say, the water temperature of the central air-conditioning main engine should be low enough. Under normal circumstances, the outlet water is 7℃ and the return water is 12℃. When the return water temperature is ≥15℃, the cooling effect is not very good. If necessary, an additional main engine should be opened.
2. There is air in the pipeline. Generally, the exhaust valve can be opened directly. Sometimes, due to pipeline installation problems, the air does not gather at the position of the emptying valve, so the pipeline can only be removed for emptying.
Methods: Close the two water supply and return valves of the fan coil, remove the pipeline between the electric valve and the return valve, connect it to the interface of the electric valve with a long enough water pipe, and open the water supply valve gently. If there is air in it, the air in the water supply pipe has been exhausted. If it is necessary to exhaust the air in the return pipe, close the two water supply and return valves and remove the connecting pipe between the filter and the water supply valve.
Attention and skills:
Generally, air is collected in the return pipe. The joint between the drain pipe for air removal and the coil fittings must be tightened and must not be grasped by hand, and the hand for opening the valve should not leave the valve. If there is any problem, the valve can be closed quickly, because the pipeline vibrates greatly when air removal occurs, and it is easy to shake off the drain pipe.
The filter is blocked, mainly because when the water pipe is put into use, the cleaning is not clean or the water treatment is not good, and there are impurities blocking the filter and causing no circulation. The two water supply and return valves can be closed, and the emptying valve can be opened to ensure that there is no pressure in the coil, then the cleaning port of the filter can be removed and the filter screen inside can be taken out and cleaned.
The electric valve can’t be opened or is blocked by dirt. If the electric valve can’t be opened, the temperature control is damaged. If there is no power to the electric valve, and the gears in the motor box of the electric valve are worn out, the motor box can be disassembled for inspection. The electric valve has no power to check the temperature controller.
