Fan coil unit maintenance in late autumn

Late autumn is a crucial period for air conditioning systems to transition from cooling to heating mode. Maintaining the fan coil units at this time not only removes dirt accumulated during the summer but also prepares them for winter heating. The following are key points for systematic maintenance:

I. Pre-shutdown inspection and cleaning

1. Disconnect the power supply.

Turn off the power switch of the fan coil unit and lock and label the distribution box to ensure safe operation.

2. Clean the return air filter.

Remove the return air filter, rinse it with clean water or a neutral detergent, let it air dry, and then reinstall it. If the filter is damaged or severely deformed, it should be replaced with a new one. Dust accumulates in late autumn, so it is recommended to check it every two weeks.

3. Clean the coil fins.

Spray with a dedicated fin cleaner, let stand for 5-10 minutes, then rinse with a low-pressure water gun along the direction of the fins. If the fins are bent over, straighten them with a fin comb to ensure proper ventilation. Take care to protect the fins and avoid damaging them with a high-pressure water gun.

4. Clean the condensate pan and drain pipe.

Remove accumulated dust, debris, and biofilm from the condensate pan. Flush the drain pipe with clean water and unclog it with a drain cleaner if necessary to ensure proper drainage. You can place anti-mold tablets in the condensate pan or add fungicide periodically.

5. Inspect the fan and motor.

Manually rotate the fan impeller to check for jamming or abnormal noise. Inspect the motor bearings and add lubricating oil if necessary. Measure the motor insulation resistance; if it is below 0.5MΩ, it should be repaired or replaced. Check the fan capacitor for bulging or leakage.

II. Special maintenance for seasonal transitions

1. Inspection of electric valves/temperature control valves

Before switching to heating mode in late autumn, check if the electric two-way or three-way valve operates smoothly. Manually test the valve core opening and closing to prevent it from jamming due to prolonged disuse during the summer. Check if the thermostat settings and valve linkage are normal.

2. Water system inspection

Check the supply and return water pipes for leaks and damage to the insulation layer. Drain the system to remove rust and residue accumulated during summer operation. Inspect the Y-type filter, cleaning or replacing the filter screen. Confirm that the system's water replenishment and pressure regulation are normal.

3. Exhaust treatment

Open the exhaust valve at the highest point of the fan coil unit to purge the air from the coil and prevent air blockage that could lead to poor heating performance. If the system frequently produces gas, check the quality of the makeup water or whether there is negative pressure suction.

4. Insulation Inspection

Check the insulation layer of the supply and return water pipes and condensate pipes for damage, and repair any damaged areas promptly to prevent them from freezing and cracking in winter.

III. Heating Mode Trial Operation

Switch the thermostat to heating mode and observe whether the air outlet temperature rises normally. Check for leaks, unusual noises, or vibrations.

Confirm that all fan speed settings are normal. Record the operating current and compare it with the rated value to determine the motor's condition.

IV. Long-term discontinuation (if not used during winter)

Drain any water from the coils to prevent them from freezing and cracking (especially in northern areas without heating). Dry the coils with compressed air. Close the supply and return water valves and label them appropriately. Place a desiccant in the control box to prevent components from getting damp.

V. Maintenance Cycle Recommendations

VI. Precautions

Before maintenance, always disconnect the power and turn off the water to prevent electric shock and flooding. Use neutral or specialized cleaning agents to avoid corroding the fins and condensate pan. Exercise caution when working at heights; two people should work together if necessary. Complete a record after maintenance for traceability and future planning.

• GO TO PLATFORM：  in      X