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FORM 201.19-CL1 (309)

JOHNSON CONTROLS 

3

Programmed Settings

Ensure  the  system  cut-out  and  operational  settings 

are  in  accordance  with  the  instructions  provided  in 

Section 8 of the IOM and with the general chiller op-

erational requirements by pressing the 

Program

 key. 

The chilled liquid temperature control settings need to 

be set according to the unit model and required operat-

ing conditions.

 

Date and Time

Program the date and time by first ensuring that the 

CLK jumper J18 on the microprocessor board is in the 

ON position (top two pins). Then press the 

Clock Set 

Time

 key and set the date and time.

Start/Stop Schedule

Program the daily and holiday start/stop by pressing the 

Set Schedule/Holiday

 key.

Setpoint and Remote Offset

Set  the  required  leaving  chilled  liquid  temperature 

setpoint and control range. If remote temperature reset 

(offset) is to be used, the maximum reset must be pro-

grammed by pressing the 

Remote Reset Temp

 key. 

First time start-up

During the commissioning period there 

should be sufficient heat load to run 

the unit under stable full load opera

-

tion to enable the unit controls, and 

system operation to be set up correctly 

and a commissioning log taken. Be 

sure that the Micro Panel is properly 

programmed and the System Start-up 

Check List is completed.

Interlocks

Verify that liquid is flowing through the evaporator and 

that heat load is present. Ensure that any remote run in-

terlocks are in the run position and that the run schedule 

requires the unit to run or is overridden.

System Switches

Place the 

Sys 1

 switch on the microprocessor board 

to the 

ON

 position.

Start-up

Remove the locking device from the unit Auto/OFF 

switch which prevents unauthorized starting of the unit 

before commissioning. Press the 

Status

 key, then turn 

the unit switch to the “1” position to start the unit (there 

may be a few seconds delay before the first compressor 

starts because of the anti-recycle timer). Be ready when 

each compressor starts, to switch the unit OFF immedi-

ately if any unusual noises or other adverse conditions 

develop. Use the appropriate emergency stop device if 

necessary.

 

Oil Pressure

When a compressor starts, press the relevant 

System 

Pressures

 key and verify that oil differential pressure 

develops immediately (Discharge Pressure minus Oil 

Pressure). If oil pressure does not develop, the automatic 

controls will shut down the compressor. Under no cir-

cumstances should a restart attempt be made on a com-

pressor which does not develop oil pressure immediately. 

Switch the unit switch to the 

0

 position (OFF).

Refrigerant Flow

When a compressor starts, a flow of liquid refrigerant 

will be seen in the liquid line sight glass. After several 

minutes operation and providing a full charge of refrig-

erant is in the system, the bubbles will disappear and be 

replaced by a solid column of liquid.

Fan Rotation

As discharge pressure rises, the condenser fans oper-

ate in stages to control the pressure. Verify that the fan 

operation is correct for the type of unit.
 

Suction Superheat

Check  suction  superheat  at  steady  full  compressor 

load only. Measure suction temperature on the copper 

line about 6" (150 mm) before the compressor suction 

service valve. Measure suction pressure at the compres-

sor service valve. Superheat should be 10°F to 12°F  

(5.6°C to 6.7°C).

Expansion Valve 

The  electronic  expansion  valves  are  factory  set  and 

should not need adjustment. 

Summary of Contents for YORK YCAS0098-0208

Page 1: ...rating charge Reference the Technical Data Section in the IOM Valves Open each compressor suction economizer and dis charge valve fully counter clockwise then close one turn of the stem to ensure operating pressure is fed to the pressure transducers Open the liquid line service valve fully and ensure the oil return line ball valve is open in each system Compressor Oil To add oil to a circuit conne...

Page 2: ... above 96 F 36 C the compressor heaters must be on for at least 8 hours before start up to ensure all refrigerant liquid is driven out of the compressor If the ambient temperature is below 86 F 30 C then allow 24 hours Water System Verify that the chilled liquid system has been installed correctly and has been commissioned with the correct direction of water flow through the evaporator The inlet s...

Page 3: ...position Start up Remove the locking device from the unit Auto OFF switch which prevents unauthorized starting of the unit before commissioning Press the Status key then turn the unit switch to the 1 position to start the unit there may be a few seconds delay before the first compressor starts because of the anti recycle timer Be ready when each compressor starts to switch the unit OFF immedi atel...

Page 4: ...line temperature on the copper line beside the main liquid line service valve Measure liquid pressure at the liquid line service valve Sub cooling should be 12 F to 15 F 6 7 C to 8 3 C No bubbles should show in the sight glass If subcooling is out of range add or remove refrigerant as required Do not overcharge the unit The liquid flow to the main evaporator TXV is subcooled further by the economi...

Page 5: ...delivery tubing With the bottom suction end of the pump submerged in oil to avoid entrance of air operate the pump until oil drips from the flare nut joint allowing the air to be expelled and tighten the flare nut Open the oil charging valve on the oil separator and pump in oil until it reaches the proper level as described above In actual operation due to splashing an oil level may be seen in bot...

Page 6: ...lve electronic should always be selected when an EEV is installed Verify the selections by pressing the OPTIONS Key on the control panel Check them off in the chart above Damage to the chiller could result if switches are improperly pro grammed 5 Program the required operating values into the micro for cut outs safeties etc and record them in the chart below Record programmed values in the chart b...

Page 7: ...scharge condensing pressure can be found in the refriger ant temperature pressure chart use entering air temperature 30 F 17 C for normal condens ing temperature b The temperature of the liquid refrigerant out of the condenser should be not be more than 15 F 8 C less than the condensing temperature The temperature corresponding to the condensing pressure from the refrigerant temperature pres sure ...

Page 8: ...on superheat should be checked The superheat should be checked only after steady state operation of the chiller has been established the leaving water temperature has been pulled down to the required leaving water temperature and the unit is running in a fully loaded condition Correct superheat setting for a system is 10 12 F 6 7 C The superheat is calculated as the difference between the actual t...

Page 9: ...mately 15 minutes between adjustments for the system and the thermal expansion valve to respond and settle out Assure that superheat is set between 10 12 F 6 7 C 1 Record the motor gas temperature economizer pressure economizer pressure converted to temperature and economizer superheat below SYS 1 SYS 2 Economizer Press PSIG kPa Economizer Temp F C Economizer Press Converted to Temp F C Superheat ...

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