York YCUL0045E, Installation Operation & Maintenance

Page: 77 / 144

JOHNSON CONTROLS
77
FORM 150.63-NM8 (1020)
2
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 Control On-Pressure is the programmed pres-
sure value that is used to stage the condenser fans on, in
relation to discharge pressure.
Refer to Condenser Fan
Control in the UNIT OPERATION section and Tables
23 & 24.
The microprocessor will not allow
programming the “FAN CONTROL
ON PRESSURE” minus the “FAN
CONTROL DIFFERENTIAL OFF
PRESSURE” below 160PSIG. This
assures discharge pressure does not
drop too low.
The Fan Differential Off Pressure is the programmed
differential pressure value that is used to stage the con -
denser fans off, in relation to discharge pressure.
Refer
to Condenser Fan Control in the UNIT OPERATION
section and Tables 23 & 24.
The microprocessor will not allow
programming the “FAN CONTROL
ON PRESSURE” minus the “FAN
CONTROL DIFFERENTIAL OFF
PRESSURE” below 160 PSIG. This
assures discharge pressure does not
drop too low.
The TOTAL NUMBER OF COMPRESSORS are the
amount of compressors in the chiller, and determines
the stages of cooling available. Notice in Table 11 that
the selection available will vary depending on the unit
model.
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
Depending on the option, the trip voltage for a
specific system or unit high current trip (See page
78) can be programmed. It also calibrates the current
readout under the OPER DATA key. The approximate
programmed value is calculated using the following
formulas:
This MUST be programmed correctly
to assure proper condensing unit op -
eration.
A single system chiller MUST have a
jumper between terminals 13 - 17 on
terminal block CTB1. If the jumper
is not installed, the unit will act as a
2-system chiller. The jumper is only
checked by the micro at unit power-up.
If the jumper is removed, power must
be removed and re-applied to register
the change in memory.
F A N C O N T R O L O N
P R E S S U R E = X X X P S I G
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