Page 101 - Fan Coil Unit

Causes of Fan Coil Unit Malfunctions and Measures of Fan Coil Unit Malfunctions and Measures
Causes

Abnormal Expected Causes and Measures
Operation Main Causes
Symptoms Detailed Causes Measures
1. Power Outage Wait until the power is restored
Request maintenance from the power company or an electrical
2. Abnormal Voltage (Below 90% of the rated voltage)
A. Power Supply Issues service company
3. Power Cord Cut or Poor Contact with the Outlet Replace the power cord or check and replace the outlet.
4. Power Plug Detachment Securely attach the power plug
B. Control Circuit and 5. Wiring Breakage and Terminal Disconnection Refer to the electrical wiring diagram to check and reconnect or repair.
Operation The fan Circuit Component 6. Fuse Breakage Replace the fuse
Malfunction
Start-up is not 7. Switch Malfunction Check the wiring arrangement and ensure there are no disconnected wires
rotating. 8. Condenser Malfunction Replace
C. Motor Malfunction
9. Motor Malfunction Replace
10. Check Operation Status Check the operational state
In the case of MICOM type, ensure the appropriate cooling or heating
D. Switch Operation 11. Select Operation Mode mode is selected
Malfunction
12. Temperature Setting Malfunction For temperature control types, check if the temperature setting is
appropriate and reset if necessary
1. Loosening of assembly screws Check and tighten as needed
2. Intrusion of foreign substances into air ducts or Remove the foreign substances
A. Abnormal noise from rotating parts
Abnormal the fan 3. Interference between the rotating assembly and housing Adjust the gap by loosening the rotating body fixing bolt
noise or
vibration 4. Damage to the rotating assembly Replace
occurs 5. Defect of the motor Check and repair or replace as needed
during B. Heat Exchanger 6. Air in the heat exchanger Perform air purging
operation
7. Poor fastening of fixing bolts Tighten the bolts securely
C. Product 8. Missing dustproof grille Install the dustproof grille
9. Contact with other structures Resolve contact points
10. Abnormal low supply power voltage Contact the power company or an electrical contractor for improvement
(Below 90% of the rated voltage)
Low 11. Obstruction in the air inlet/outlet Remove foreign objects
air volume The air volume is low.
12. Clogged air filter Clean the filter
13. Incorrect motor or condenser capacity Check the capacity of the motor and condenser and replace if necessary
A. The air volume is low. 14. Check items 10 to 13
B. Performance is
insufficient compared 15. Load calculation or equipment selection error Contact the equipment provider
to the actual cooling/
heating load
During
operation 16. Check if the valves in the piping line are closed. Check and open the valve
Reduced C. No water flow Check for improper piping connections or reverse valve installations
Cooling/ 17. Piping line errors in the line
Heating
Capacity D. Insufficient cooling/ 18. Piping design or installation error Contact the equipment provider
heating water volume 19. Insufficient capacity of the circulation pump Contact the equipment provider
20. Supply water temperature below the design Check and improve the capacity of the refrigeration unit or boiler
E. Lack of a heat source temperature
Check the insulation status of the piping and reinforce if necessary
F. Decreased heat
exchange efficiency 21. Contamination of the heat exchanger (coil) fins Check and clean contamination of the heat exchanger
22. Improper coupling of the drain hose Check and secure the coupling properly
23. Absence of an air vent on the drain pipe Install an air vent at the end of the hose
Check if the drain pipe has the appropriate diameter and slope, and
24. Defective drain piping
A. Condensate water take corrective measures
drainage issue 25. Foreign material entering the drain pump Check for foreign material and remove it
Leakage
from the 26. Malfunction of the drain pump Inspect and replace if necessary
product For pump-built-in types, check the drain height and modify the piping
27. Inadequate drain height
if needed
B. Piping connection 28. Poor connection of each pipe joint Check and reassemble the packing or sealing
Leakage 29. Insufficient insulation Check the insulation of the connected pipes and reinstall if necessary
C. Poor installation 30. Poor state of balance Install horizontally using a level gauge
the fan 1. Switch malfunction Inspect and replace if necessary
When Electrical circuit
stopped, does not malfunction 2. Control circuit abnormality Inspect and replace (In the case of MICOM type, the operation stops
stop. after a certain period.)

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