JOHNSON CONTROLS
129
SECTION 5 – SEQUENCE OF OPERATION
FORM 145.05-NOM7
ISSUE DATE: 10/31/2019
5
• Wait 1 minute
• Turn the “PUMP START” DO to OFF
Change “CURRENT OPER MODE” back to previous
mode and resume normal operation.
Pump / Aux Output On CTB1
(Also Used For Isolation Damper Control)
The Unit Controller has a dry contact that is used to
close a circuit to a condenser water pump or an isola-
tion damper. The contact is located at terminal block
TB1 – terminal 11 and 12. The rating of the contact is
24 to 120VAC, 40MA to 1 AMP. This feature is pro-
vided as a convenience.
The condenser water pump does not have to be con-
nected and operated in this way.
The relay contact is closed whenever the UNIT MODE
is as follows:
• OCCUPIED STANDBY
• OCCUPIED COOLING
• UNOCCUPIED COOLING
In addition, the relay contact is closed if a “WRN-
FREEZESTAT TRIP” or “LOCKOUT – HOT WATER
FREEZE” fault is active.
When PUMP START turns on, a timer begins. For the
first 60 seconds after PUMP START is turned on, com-
pressors are inhibited from operating. If PUMP START
is turned OFF, the compressors do not operate; but
again, the use of these contacts are not needed.
To ensure that there is sufficient water flowing through
the condenser while using the PUMP/ AUX contacts
for the condenser water pump, a 60-second timer starts
when “CURRENT OPER MODE” transitions from a
non-cooling to a COOLING mode. Compressors are
inhibited from operating until this timer expires.
Isolation Damper Control
On some units, dampers keep the unit isolated from
the supply and return duct systems. On these systems,
the ISOLATION DAMPER must be opened before the
SUPPLY FAN OUTPUT is turned on, and it must be
turned off once the SUPPLY FAN OUTPUT is turned
off.
If the ISOLATION DAMPER CONTROL is User En-
abled, the PUMP/ AUX contacts is turned ON when
the preceding conditions are met and when these con-
ditions remain in force for 120 seconds. The SUPPLY
FAN OUTPUT is energized after a delay for 120 sec-
onds to assure any dampers are fully open; the PUMP/
AUX contacts remain on for 60 seconds after the SUP-
PLY FAN OUTPUT turns OFF, allowing the static
pressure to decrease.
Any time the SUPPLY FAN OUTPUT is turned OFF,
the ISOLATION DAMPER is also turned OFF if it is
ENABLED and active.
• PROGRAM key, UNIT DATA subsection: “ISO-
LATION DAMPER CONTROL” is set to EN-
ABLED
If the preceding conditions do not remain in force for
120 seconds, the ISOLATION DAMPER is turned
OFF.
The SUPPLY FAN OUTPUT turns OFF if all of the
following conditions are met:
• The SUPPLY FAN OUTPUT has been ON for at
least 60 seconds of its minimal run time
• All Heating Binary Outputs are off for at least 60
seconds (ELECTRIC HEAT STG 1 ELECTRIC
HEAT STG 2, ELECTRIC HEAT STG 3, and
ELECTRIC HEAT STG 4)
• All COMPRESSOR Binary Outputs are off for at
least 60 seconds (COMPRESSOR A, B, C, D, E,
and F)
• OCCUPANCY MODE is set to UNOCCUPIED
• “CURRENT OPER MODE” is UNOCCUPIED
STANDBY
• UNDER FLR TEMP OVRD is INACTIVE
• SUPPLY AIR TEMP CURRENT is less than or
equal to 85.0°F (if this input is invalid, ignore it)
If HIGH DUCT STATIC is faulted and any of AUTO
RESET-DUCT PRESS 1, AUTO RESET-DUCT
PRESS 2, or LOCKOUT-HIGH DUCT PRESS SW
are active, turn OFF the SUPPLY FAN OUTPUT. Re-
sume normal operation 60 seconds after these condi-
tions clear.
Any time the SUPPLY FAN OUTPUT is turned OFF,
the ISOLATION DAMPER also turns OFF.