Daikin Water Chiller WSC113

Calibrate Temperature Transducers

Check Vane Control Setting and Operation

Verify Motor Load Limit Control

WSC and WDC water chillers are leak tested at the factory and shipped with the correct charge of refrigerant as indicated on the unit nameplate.

In the event the refrigerant charge was lost due to shipping damage, the system should be charged as follows after first repairing the leaks and evacuating the system.

Connect the refrigerant drum to the gauge port on the liquid line shutoff valve and purge the charging line between the refrigerant cylinder and the valve. Then open the valve to the mid-position.

Turn on both the cooling tower water pump and chilled water pump and allow water to circulate through the condenser and the chiller. (It will be necessary to manually close the condenser pump starter.)

If the system is under a vacuum, stand the refrigerant drum with the connection up, and open the drum and break the vacuum with refrigerant gas to a saturated pressure above freezing.

With a system gas pressure higher than the equivalent of a freezing temperature, invert the charging cylinder and elevate the drum above the condenser. With the drum in this position, valves open, water pumps operating, liquid refrigerant will flow into the condenser. Approximately 75% of the total requirement estimated for the unit can be charged in this manner.

After 75% of the required charge has entered the condenser, reconnect the refrigerant drum and charging line to the service valve on the bottom of the evaporator. Again purge the connecting line, stand the drum with the connection up, and place the service valve in the open position.

IMPORTANT: At this point, the charging procedure should be interrupted and prestart checks made before attempting to complete refrigerant charge. The compressor must not be started at this time. (Preliminary check must first be completed.)

NOTE: It is of utmost importance that all local, national, and international regulations concerning the handling and emission of refrigerants are observed.

Maintenance of the electrical system involves the general requirement of keeping contacts clean and connections tight and checking on specific items as follows:

1. The compressor current draw should be checked and compared to nameplate RLA value. Normally, the actual current will be lower, since the nameplate rating represents full load operation.

Also check all pump and fan motor amperages, and compare with nameplate ratings.

2. Inspection must verify that the oil heaters are operative. The heaters are insert-cartridge type and can be checked by ammeter reading.

They should be energized whenever power is available to the control circuit, when the oil temperature sensor calls for heat, and when the compressor is inoperative.

When the compressor runs, the heaters are de-energized. The Digital Output screen and second View screen on the operator interface panel both indicate when the heaters are energized.;

Warning: This maintenance check requires trained personnel with PPE!

Enter the leaving water temperature

Enter the saturated refrigerant temperature

Calculate the approach temperature (subtract saturated refrigerant temperature from leaving water temperature)

Note: Daikin's high efficiency heat exchangers have very low design approach temperatures, in the order of one to one and one half degrees F.

Is the approach temperature within the normal range?

If the approach temperature is not within the normal range, it could indicate excessive tube fouling.

Enter the condenser pressure drop

Is the chiller subject to freezing temperatures?

If yes, drain the condenser and chiller of all water.

Did you use dry air to force all water out of the condenser?

Did you remove the condenser heads?

Warning: Water left in the piping and vessels can rupture these parts if subjected to freezing temperature.

Did you circulate antifreeze through the water circuits?

Did you take measures to prevent the shutoff valve in the water supply line from being accidentally turned on?

If a cooling tower is used, did you remove the pump drain plug?