York MAXE OPTIVIEW YK, Service Instructions Manual

Page: 144 / 180

YORK INTERNATIONAL
144
FORM 160.54-M1(503)
allowed vane pulse is limited to 3.5 seconds at the 25%
PRV position and 0.9 seconds at 0% position. PRV posi-
tions in between have linearly scaled maximums.
Proceed as follows to select this value:
1. At the Keypad, log in at SERVICE access lev el
us ing access code 1 3 8 0.
2. Select EVAPORATOR Screen.
3. Press SENSITIVITY key.
4. Use
◄ and ► keys to select desired value.
5. Press ENTER (
✔
) key.
DROP LEG REFRIGERANT TEMPERATURE
The chiller can be equipped with a refrigerant tem per a-
ture sensor in the drop leg between the condenser and
evaporator. If “Enabled” with the procedure below, this
temperature is displayed on the CONDENSER Screen
as the “Drop Leg Temperature”. It is subtracted from
the Condenser Saturation Temperature to produce “Sub
Cooling Temperature”, also displayed on the Con dens er
Screen. If the chiller is equipped with the Drop Leg Re-
frigerant Temperature sensor, the values are dis played
on the CONDENSER Screen only if enabled with the
following procedure.
1. At the Keypad, log in at SERVICE access Level
us ing access code 1 3 8 0.
2. Select CONDENSER Screen.
3. Press DROP LEG key.
4. Use
◄ and ► keys to select Enable or Disable.
5. Press ENTER (
✔
) key.
SMART FREEZE PROTECTION
This feature is described in the “Smart Freeze Pro-
tec tion” section of this book. When turned on, it allows
the Leaving Chilled Liquid Temperature Setpoint to be
as low as 36ºF for water cooling applications. Along
with this feature is a correspondingly lower Low Water
Tem per a ture Cycling Shutdown threshold and Low
Evap o ra tor Pressure Safety Shutdown threshold. The
Smart Freeze Protection feature can be turned ON or
OFF using the following procedure:
1. Shutdown the chiller and wait for completion of
COASTDOWN.
2. At the Keypad, log in at SERVICE access lev el
us ing access code 1 3 8 0.
3. Select EVAPORATOR Screen.
4. Press SMART FREEZE key.
5. Use
◄ and ► keys to select ON or OFF.
6. Press ENTER (
✔
) key.
EVAPORATOR REFRIGERANT TEM PER A TURE
If the chiller is equipped with an Evaporator Re frig er ant
Temperature sensor, the feature must be Enabled with
the procedure below. If not equipped with this sen sor,
it must be Disabled. If enabled, this temperature is dis-
played on the EVAPORATOR Screen, and is also used
in the Smart Freeze Protection Low Evap o ra tor Pres sure
Safe ty Shutdown threshold calculation, as ex plained in
the “Smart Freeze Protection” section of this book.
Use the following procedure to Enable or Disable this
feature:
1. At the keypad, log in at SERVICE access lev el
us ing access code 1 3 8 0.
2. Select EVAPORATOR Screen.
3. Press REFRIGERANT key.
4. Use
◄ and ► keys to select Enabled or Dis-
abled.
5. Press ENTER (
✔
) key.
HOT GAS BYPASS CONTROL
A complete description of the optional Hot Gas Bypass
Control and the Setpoints that affect this control are
pro vid ed in the “Hot Gas Bypass” section of this book.
The Setpoints are listed below. If the chiller is equipped
with this feature, it must be “Enabled” and the setpoints
programmed using the procedure below. Otherwise, it
must be “Disabled”. The Hot Gas valve can be man u al ly
controlled using the procedure below. The total life time
Surge Count can be cleared. However, this should NOT
be arbitrarily performed! Since the Pre-Rotation Vanes
(PRV) position is used in the Hot Gas control, the PRV
position feedback potentiometer must be cal i brat ed with
the procedure below.
Enable/Disable:
If the chiller is equipped with the optional Hot Gas By pass
control, operation must be “enabled”. Oth er wise, it must
be “disabled”. Use the following pro ce dure:
1. Shutdown chiller and place COMPRESSOR Start/
stop Switch in the Stop-Reset (O) position.
2. At the Keypad, log in at SERVICE access lev el,
us ing password 1 3 8 0.
3. Select SETPOINTS Screen. From SETPOINTS
Screen, select SETUP Screen. From SETUP Screen,
select OPERATIONS Screen.
4. Use ◄ and ► keys to select Enable or Dis able.
5. Press ENTER (
✔
) key.
System Calibration