York Screw Chiller YCIV0227PA46

The following maintenance checks should be carried out on a daily basis by the operator/customer

The units are not generally user serviceable

No attempt should be made to rectify faults or problems found during daily checks unless competent and equipped to do so

If in any doubt, contact your local Johnson Controls Service Agent

Unit status: Press the STATUS key on the keypad and ensure no fault messages are displayed

Operating conditions: Read the operating pressures and temperatures at the control panel using the display keys

Check that these are within the operating limitations given in the manual

Compressor oil level: Check the compressor oil level after the compressor has been operating on FULL LOAD for approximately half an hour

Connect a high-capacity vacuum pump with indicator to the charging valves as shown in Figure 147 on page 306 and Figure 148 on page 306

Ensure all the system valves including manual valves and EEVs are 100% open

Ensure that all valves to the atmosphere are closed with flare caps in place, if applicable

Operate the vacuum pump until a pressure of 5,000 μm is reached

To start the 8-hour vacuum hold test, close the system charging valve connection to the vacuum pump

Hold the vacuum obtained in Step 4 in the system for 8 hours

Check for pressure change with the chiller at the same temperature

Warning: This procedure requires trained personnel with PPE!

Enter the amount of chiller refrigerant charge

Reference the unit Sales Order screen on the chiller control panel to determine the required charge

Enter the evaporator approach (STD)

For new sales, these design values are included as part of the FOF

If not included, they can be provided upon request from the chiller sales engineer from the chiller rating program

Equations: Evaporator approach = (LCHLT) - (EST), Discharge superheat = (DT) - (CST), Subcooling = (CST) - condensed refrigerant liquid temperature (from condenser outlet)

Refrigerant charge removed and all known leaks repaired?

System charged with a small amount of refrigerant mixed with dry nitrogen?

Used an electronic leak detector to detect any leaks that are too small to be found by the soap test?

Care taken not to exceed the rated pressure of the unit refrigerant pressure relief valves?

Conducting the gas pressure hold test

High-quality, high-resolution analog pressure gauge installed on one of the service valves?

All the system valves including manual valves and EEVs are 100% open?

All valves to the atmosphere are closed with flare caps in place, if applicable?

Warning: This procedure should only be performed by a qualified technician.

Has the system been carefully pressure tested and evacuated at the factory?

Enter the leak rate for a 100% pure R-134a system at DWP

Are all joints tight and leak-free?

If any leaks are indicated, they must be repaired immediately.

Has the system been carefully leak tested with a compatible leak detector during operation?