Daikin Water Chilling Unit C7-UWJ2650B5Y

- Check refrigerant charge using the condenser liquid level gauge (refrigerant is within range on the gauge)

- Check refrigerant oil charge using the compressor oil gauge (refrigerant oil is within range on the gauge)

- Check water quality (according to JIS K0101 or this manual; see water quality standards on page 50);

Close the stop valve on the condenser outlet

If the pressure switch (Low pressure protection) trips, shut compressor discharge stop valve

Do not short-circuit the pressure switch (Low pressure protection) or the temperature switch (discharge gas) for any reason whatsoever

Operate the compressor for about 15 minutes before performing pump down

Sign off on the Chilling Unit Pump Down

Warning: Ensure the cooling tower is turned off before starting the cleaning process.

Is the condenser visibly dirty?

If the condenser is not dirty, no cleaning is required. If it is dirty, proceed with the cleaning process.

Describe the type of dirt or debris found on the condenser.

Is there any scale or fungus formation inside the cooling tower?

If there is scale or fungus formation, it needs to be cleaned immediately to prevent safety device tripping and to ensure normal operation.

Is the water quality in the area poor?

If the water quality is poor, the condenser needs to be cleaned more frequently.

Record the frequency of cleaning cycles.

Caution: Never touch parts which tend to become hot such as compressors and refrigerant piping. Doing so could result in skin burning. Do not attempt to run the compressor by pushing the magnetic contactor with your finger. Doing so could result in electrical shock or fire.

Check open-closed state of all valves before usage

Check valves against instructions given in the operation manual and on the nameplate

Ensure safety valves are open while the equipment is running

If valves are open or closed when they shouldn't be, water may leak. In worse cases, the equipment may catch fire or explode.

Before inspecting: It would be a good idea to read “SAFETY” once more before starting inspection. Be sure to let other maintenance technicians know that you are going to inspect the chiller. Push the STOP/RESET button to stop the unit. Place an “under inspection” warning sign on the switch box.

Drain some of the water from the air purge plug

If the water is dirty, replace all the water in the system

To maintain the unit in prime operating condition, check the following items daily, making adjustments where necessary and keeping a record of all checks. Values under “Passing grade” are indicated for chiller under typical operating conditions.

Check discharge pressure gauge (1.1–1.7 MPa when cooling; 1.5–1.8 MPa when heating)

Check discharge pressure difference between left and right compressors (for 2-compressor circuits, max. 0.1 MPa)

Check suction pressure using the compound gauge (0.3–0.6 MPa when cooling; 0.3–0.6 MPa when heating)

Check suction pressure difference between left and right compressors (for 2-compressor circuits, max. 0.05 MPa)

Check power supply voltage with a voltmeter (within ±10% of rated voltage)

Check condenser water outlet temperature (30–40 °C)

Check chilled (hot) water outlet temperature (5–10 °C when cooling; 40–45 °C when heating)

Check for abnormal vibrations and noises (no abnormal vibrations or noises)