Johnson Controls York YKEP, Operation And Maintenance

FORM 160.77-O1  

ISSUE DATE: 10/22/2020

JOHNSON CONTROLS

18

SECTION 2 - SYSTEM OPERATING PROCEDURES

NEED FOR MAINTENANCE OR SERVICE

If the system is malfunctioning in any manner or the 

unit is stopped by a safety shutdown, refer to the Opera-

tion Analysis Chart shown in 

SECTION 4 - TROUBLE-

SHOOTING

Table 3 on Page 31

. After consulting 

this chart, if you are unable to make the proper repairs 

or adjustments to start the compressor or the particular 

trouble continues to hinder the performance of the unit, 

please call the nearest Johnson Controls District Of-

fice. Failure to report constant troubles could damage 

the unit and increase the cost of repairs.

STOPPING THE SYSTEM

The YKEP Control Center can be programmed to start 

and stop automatically (maximum - once each day). 

For more information on this refer to the YKEP

 Con-

trol Center Operation Manual (Form 160.77-O2)

. 

To stop the chiller, proceed as follows:

1.  Push the soft shutdown key on the homescreen of 

the Control panel. The compressor will stop auto-

matically. Normal stop raises the driveline to stop 

and should always be used instead of the E-Stop 

during regular operation.

2.  Stop the chilled water pump (if not wired into the 

Control Center, in which case it will shut off auto

-

matically simultaneously with the oil pump).

BRINE APPLICATIONS  When the chill

-

er is not running, brine should not be run 

through the evaporator. However, if there 

is brine running through the evaporator, 

there must be flow through the condenser 

to prevent tubes from freezing.

3.  Open the switch to the cooling tower fan motors, 

if used.

In the event of an unusual circumstance 

requiring immediate stoppage, an emer-

gency stop switch is located on the side of 

the control panel. 

PROLONGED SHUTDOWN

If the chiller is to be shut down for an extended period 

of time (for example, over the winter season), the fol-

lowing procedure should be followed.

1.  Test all system joints for refrigerant leaks with a 

leak detector. If any leaks are found, they should 

be repaired before allowing the system to stand 

for a long period of time.

During long idle periods, the tightness of 

the system should be checked periodically.

2.  If freezing temperatures are expected while the 

system is idle, carefully drain the cooling water 

from the cooling tower, condenser, condenser 

pump, and the chilled water system pump and 

coils.
Open the drains on the evaporator and condenser 

liquid heads to assure complete drainage. 

3.  Drain the VSD cooling system and/or the Solid 

State Starter cooling loop. If freezing tempera-

tures are expected for periods longer than a few 

days, the refrigerant should be evacuated to con-

tainers to prevent leakage from O-ring joints.

4.  Open the main disconnect switches to the com-

pressor motor, condenser water pump, and the 

chilled water pump. Open the 115 volt circuit to 

the Control Center.