Variable Frequency Drives; Maintenance; Recommended Maintenance Schedule; Coil Maintenance And Cleaning - Carrier 09FC020 Installation, Start-Up And Maintenance Instructions

9. Finned surfaces should remain wet with cleaning solution for
10 minutes.
10. Ensure surfaces are not allowed to dry before rinsing. Reap-
ply cleaner as needed to ensure 10-minute saturation is
achieved.
11. Thoroughly rinse all surfaces with low velocity clean water
using downward rinsing motion of water spray nozzle. Pro-
tect fins from damage from the spray nozzle.

Variable Frequency Drives

The 09FC units are equipped with VFDs to control the fan motors.
The drives each include an LCD user interface display. This dis-
play will show the drive status and details of any alarm. The VFDs
are configured at the factory and should not be changed. The set-
tings are listed in Table 12 for reference.
The 09FC units use VFDs that operate by an enable signal and an
analog (0-10Vdc) signal to the drive. Refer to schematic for con-
nection details.

MAINTENANCE

Recommended Maintenance Schedule

The following are only recommended guidelines. Jobsite condi-
tions may dictate that maintenance schedule is performed more of-
ten than recommended.
Routine:
• Periodic clean water rinse, especially in coastal and indus-
trial applications.
• Check heat exchanger coils for debris, clean as necessary.
Every 3 months:
• Check all joints and valves for leaks, repair as necessary.
• Check chilled water flow switch operation.
• Check all fan motors for proper operation.
Every 12 months (for all machines):
• Check all electrical connections, tighten as necessary.
• Inspect all contactors and relays, replace as necessary.
• Check accuracy of thermistors, replace if greater than ±
2°F (1.2°C) variance from calibrated thermometer.
• Check to be sure that the proper concentration of anti-
freeze is present in the chilled water loop, if applicable.
• Verify that the chilled water loop is properly treated.
• Check chilled water strainers, clean as necessary.
• Check condition of condenser fan blades and that they are
securely fastened to the motor shaft.
• Perform Service Test? to confirm operation of all compo-
nents.
• Check for excessive cooler approach (Leaving Chilled Wa-
ter Temperature - Ambient Temperature) which may indi-
cate fouling. Clean heat exchanger/chilled water loop if
necessary.

Coil Maintenance and Cleaning

Routine cleaning of coil surfaces is essential to maintain proper
operation of the unit. See page 60.
61