JOHNSON CONTROLS
128
FORM 150.72-ICOM6
ISSUE DATE: 12/29/2017
SECTION 7 – UNIT CONTROLS
This MUST be programmed correctly to
assure proper chiller operation.
N U M B E R O F F A N S
P E R S Y S T E M = X
The Number of Fans Per System must be programmed
as needed to match the number of fans on each system.
S Y S X T R I P V O L T S
= X . X V O L T S
U N I T T R I P V O L T S
= X . X V O L T S
F A N D I F F E R E N T I A L O F F
P R E S S U R E = X X X P S I G
The Fan Differential Off Pressure is the programmed
differential pressure value that is used to stage the
condenser fans OFF, in relation to discharge pressure.
See Standard Condenser Fan Control on page 154
in SECTION 8 – UNIT OPERATION and Table 22 on
page 156 and Table 23 on page 157.
T O T A L N U M B E R O F
C O M P R E S S O R S = 6
The TOTAL NUMBER OF COMPRESSORS is the
total quantity of compressors in the chiller, and deter-
mines the stages of cooling available. Note in Table
13, the chiller may have single or dual systems. Single
system units can have 2 or 3 compressors, while dual
system units may have 4 or 6 compressors.
TABLE 13 - PROGRAM KEY LIMITS AND DEFAULT
PROGRAM VALUE MODE LOW LIMIT HIGH LIMIT DEFAULT
DISCHARGE PRESSURE CUTOUT —
325 PSIG 575 PSIG 570 PSIG
22.4 BARG 39.6 BARG 39.3 BARG
SUCTION PRESSURE CUTOUT
WATER COOLING
80.0 PSIG 120.0 PSIG 80.0 PSIG
5.52 BARG 8.27 BARG 5.52 BARG
GLYCOL COOLING
42.0 PSIG 70.0 PSIG 44.0 PSIG
2.9 BARG 4.83 BARG 3.03 BARG
LOW AMBIENT TEMP. CUTOUT
STANDARD AMBIENT
25.0 °F 60.0 °F 25.0 °F
-3.9 °C 15.6 °C -3.9 °C
LOW AMBIENT
0 °F 60.0 °F 25.0 °F
-17.8 °C 15.6 °C -3.9 °C
LEAVING CHILLED LIQUID
TEMP. CUTOUT
WATER COOLING — —
36 °F
2.2 °C
GLYCOL COOLING
-1.0 °F 36.0 °F 36.0 °F
-18.3 °C 2.2 °C 2.2 °C
ANTI-RECYCLE TIMER — 300 SEC. 600 SEC. 600 SEC.
FAN CONTROL ON PRESSURE —
360 PSIG 485 PSIG 385 PSIG
24.8 BARG 33.4 BARG 26.5 BARG
FAN DIFFERENTIAL OFF PRESSURE —
80 PSID 160 PSID* 125 PSID
5.51 BARD 11.03 BARD* 8.62 BARD
TOTAL NUMBER OF COMPRESSORS
SINGLE SYSTEM 2 3 3
DUAL SYSTEM 4 6 6
NUMBER OF FANS PER SYSTEM — 2 4 3
UNIT/SYSTEM TRIP VOLTS CURRENT FEEDBACK 0.5 Volts 4.5 Volts 2.5 Volts
REMOTE UNIT ID — 0 7 0
* The minimum discharge pressure allowed is 235 PSIG. The Fan Differential Off Pressure High Limit will be lowered (reduced) to prevent
going below 235 PSIG based on where the fan control On Pressure is programmed.
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