As the most common component of HVAC systems, fan coil unit failures can generally be divided into the following categories:
- Low Airflow from the Fan, Poor Air Conditioning Performance When the fan operates normally, if the airflow is low, it could be due to either inadequate intake or air leakage in the ducts. Air leakage in the ducts is rare but can be addressed effectively. However, low intake airflow is often caused by clogged return air filters. Regularly cleaning these filters is essential. If not cleaned promptly, dust and debris can accumulate on the coil fins and fan blades, leading to reduced ventilation capacity. Dust buildup on the fan impeller can also cause reduced airflow and increased fan current.
- Loud Noise from the Coil During Operation, Increasing with Higher Fan Speed Possible reasons for excessive noise include poor vibration damping during installation, resonance during operation, foreign objects in the ducts, deformed fan blades, or damaged motor bearings affecting dynamic balance.
- Coil Motor Not Rotating To troubleshoot, check if there is power at the coil connection. If there is no power output, verify the power source for any faults. Next, inspect the speed control switch. If there is power, listen for buzzing sounds or motor heating. If present, try manually rotating the impeller to check for obstructions. If the motor fails to rotate smoothly or stops at a certain angle, it may be due to damaged capacitors or bearings affecting startup performance or increased resistance.
- Normal Airflow, but Deviation in Supply Air Temperature Such issues often relate to the supply and return water system of the coil. First, check if the supply water temperature is within the normal range and ensure proper water flow. If there is a significant temperature difference between supply and return water pipes, it may be due to clogged inlet filters or air accumulation in the pipes.
- Equipment and Piping Dripping Water In construction sites, irregularly shaped components like valves, filters, and hoses often connect to the coil. Proper insulation can be challenging, especially during routine maintenance when disassembly occurs frequently. To prevent and remedy condensation water leakage, consider sloping the local piping toward the coil side
