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SMOKE PURGE MODE — Smoke Purge mode removes
smoke from the interior spaces and replaces it with fresh out-
side air. The economizer and power exhaust are required for
this function. The economizer and power exhaust are standard
on 48FM and 50FM,FS units. The economizer is a factory-
installed option and the power exhaust is a factory-installed
option or field-installed accessory on 48FK,JK and 50FK,JK
units. Smoke purge is accomplished by:
• turning supply fan on
• opening the economizer
• running the exhaust fans
• opening the exhaust dampers
INSTALLATION — To enable one or more of the possible
smoke control modes available with these units, determine the
switches required for the desired mode(s) from Table 6, field-
supply and install the appropriate switches and field wire per
Fig. 32. Switch functions are shown in Table 7.
Table 5 — Smoke Control Modes
LEGEND
*Power exhaust function required for this mode.
†Applicable to VAV units with appropriate options.
CONFIGURATION — No set points required for Smoke Con-
trol modes. Modes are activated by energizing all switches
appropriate for each Smoke Control mode.
OPERATING SEQUENCE
Fire Shutdown
— At command from the field switches (see
Table 5), all unit operation (cooling, heating, supply fan and
power exhaust) will terminate.
Pressurization
— At command from the field switches for
Pressurization mode (see Table 5):
1. Economizer dampers will open.
2. The HIR function will energize, opening room terminals
to full-open (heating) positions.
3. Supply fan will run. (If equipped with IGV: control vanes
will open. If equipped with VFD: the VFD will control to
duct static set point or best available with all terminals
open.)
4. Power exhaust dampers (if equipped) will close.
5. Power exhaust fans (if equipped) will turn off.
Evacuation
— At command from the field switches for Evacu-
ation mode (see Table 5):
1. Supply fan will turn off.
2. Economizer dampers will open.
3. Exhaust fans will run at maximum capacity.
4. Exhaust dampers will open.
Smoke Purge
— At command from the field switches for
Smoke Purge mode (see Table 5):
1. Economizer dampers will open.
2. The HIR function will energize, opening room terminals
to full-open (heating) positions.
3. Supply fan will run. (If equipped with IGV: Control vanes
will open. If equipped with VFD: the VFD will control to
duct static set point or best available with all terminals
open.)
4. Exhaust fans will run at maximum capacity.
5. Exhaust dampers will open.
Table 6 — Smoke Control Switches Required for Each Mode
*Not required on 48FM and 50FM,FS units (high capacity power exhaust units).
NOTE: All switches are shown in “as installed” (power OFF or deenergized) position. In these
positions, none of these modes will be activated; normal unit operation is permitted by the base
unit controls. To initiate any mode, all switches listed under this mode in the table must be ener-
gized, causing the depicted contact position to change from depicted positions to energized posi-
tions. Switches may be manually or electrically operated.
FUNCTION
MODE
Fire
Shutdown
Pressur-
ization
Evacuation*
Smoke
Purge*
Supply Fan
Off On Off On
IGV/VFD†
— Open/On — Open/On
Economizer
Closed Open Open Open
Return Air
Damper
Open Closed Closed Closed
Exhaust
Fans
Off Off On On
Exhaust
Damper
Closed Closed Open Open
IGV —
Inlet Guide Vane
VAV —
Variable Air Volume
VFD —
Variable Frequency Drive
FIRE
SHUTDOWN
PRESSURIZATION
EVACUATION
(Modulating Power
Exhaust)
SMOKE
PURGE
SW-1 SW-1 SW-1 SW-1
SW-2 SW-2 SW-2 SW-2
SW-4 SW-3 SW-3
SW-5 SW-5 SW-4
SW-6 SW-6 SW-9A/B
SW-9A/B SW-7
SW-8*