Vertiv Liebert CRV Plus - Page 82

Vertiv | Liebert CRV+ | User Manual 72
Maintenance of Control System
Appearance checks and simple, functionaltests, coupled with handling of control parts needs to be carried
out on the following items:
 Carry out visual checks on the power transformers and isolation transformers for any burn marks
followed by testing the output voltage (of the indoor unit and outdoor condensers).
 Check for signs of ageing on the control interface board, control board, temperature and humidity
sensor boards, and fuse boards.
 Clean the electrical control components and control board to remove dust. Debris, dust, and dirt
must be removed, preferably by a dust removing agent.
 Check and fasten the Input/Output ports on the control interface board. It should also include the
connections between the control board and control interface boards as well as between the
Temperature/Humidity sensor boards and the control interface board.
 Check the connection between the user terminals (70#, 71#, 37#, and 38#) and the control
interface board.
 Check the output connections between the control interface board and various components
including contactors and solenoid valves for liquid pipes. Inspect the input connection between
the control interface board and various components, including high pressure switches, heating
over-temperature protection switches, discharging temperature and high pressure sensors.
Specifically, check the inserting terminals such as high pressure switches and heating over-
temperature switch followed by replacing the component if it is loosened or in poor condition.
 Replace the faulty electric components such as faulty control fuses (or MCBS) and control boards.
 Check the trunking or insulation condition of the control and power cable connected to the
condenser from the indoor unit. Replace the cable, if required.
 Use a temperature /humidity measuring meter with high precision to proofread and calibrate
temperature/humidity sensor.
 Regulate the setting point. Meanwhile, check the action of the various function components
according to the control logic
 Simulate and inspect the operation-and-working states of protecting units such as high/low
pressure alarm, high/low temperature alarm, high water level alarm, and over-temperature alarm
and over-temperature protection.
 Check the sensors.