Schreiber Chillers 15MEDAC email - Manual (Page 36)

Sets and displays the main temperature setpoints.
DISCHARGE SETPOINT
DISCHARGE: The setpoint for the chilled water reservoir. This temperature will be delivered
through both pump loops.
HIST: This is the differential around the setpoint of which the system will cycle. HIST =
Histeresis.
A 50 F setpoint with a 1.0F differential means the system will turn on at 51 F and shut off at 49
F.
LOOP 2 SETPOINT
TEMP RISE: The difference in temperature of loop 2 (GCHE/GAHE loop) above the discharge
temperature which signals the second compressor to become active.
HIST: The differential around which the second compressor goes active/inactive.
Example:
§ Discharge Temp: 50F +/_ 1.0 F
§ Temp Rise: 10 F +/- 2 F.
§ Both pumps are and both compressors are enabled.
Operation:
• Compressor 1 cycles on at 51 and off at 49.
• A scan is started.
• Return temperature of loop 2 begins to rise.
• Return temperature reaches 62 F (50 + 10 + 2), compressor 2 goes active.
• Discharge Temperature now climbs to 51 F.
• Both compressors now cycle (separated by a short delay).
• Compressors pull tank temperature down to 49 F and cycle off.
• Scanning stops, retrun temperature drops below 58 (50 + 10 –2).
Compressor 2 returns to standby.
HIGH TEMPERATURE ALARM SETPOINT
SET: Sets and displays the high temperature alarm setpoint.
HIST: The differential around the setpoint which the alarm will operate.
ENABLED: Displays whether or not the high temperature alarm is enabled.
ROTATION
ENABLED/DISABLED. This controls whether or not compressor rotation will take place. When
both compressors are enable at the main ON/OFF screen, rotation mode can be selected to
be enabled or disabled. When one or of the compressors is disabled, then the controller will