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Table 83 — Power Exhaust Staging (
BP.CF
= 2)
• If building pressure (
Pressures
AIR.P
BP
) is less than
the building pressure set point (
Configuration
BP
BPSP
) minus the building pressure low threshold
level (
Configuration
BP
B.CFG
BP.LP
)
subtract
a
stage of power exhaust.
VFD POWER EXHAUST BUILDING PRESSURE CON-
TROL (
BP.CF
= 3) — A 4 to 20mA analog output from
Economizer Control Board 1 (ECB-1, AO1) is provided as a
speed reference for a field-installed VFD power exhaust
accessory. If building pressure (
Pressures
AIR.P
BP
) rises
above the building pressure set point (
BP.SP
) and the supply
fan is on, then building pressure control is initialized. Thereaf-
ter, if the supply fan relay goes off or if the building pressure
drops below the
BP.SP
minus the building pressure set point
offset (
BP.SO
) for 5 continuous minutes, building pressure
control will be stopped. The 5-minute timer will continue to re-
initialize if the VFD is still commanded to a speed > 0%. If the
building pressure falls below the set point, the VFD will slow
down automatically. Control is performed with a PID loop
where:
Error = BP –
BP.SP
K = 1000 *
BP.RT
/60 (normalize the PID control for run
rate)
P = K *
BP.P
* (error)
I = K *
BP.I
* (error) + “I” calculated last time through the
PID
D = K *
BP.D
* (error – error computed last time through
the PID)
VFD speed reference (clamped between
BP.MN
and
BP.MX
%) = P + I + D
Smoke Control Modes —
There are four smoke con-
trol modes that can be used to control smoke within areas ser-
viced by the unit: Pressurization mode, Evacuation mode,
Smoke Purge mode, and Fire Shutdown. Evacuation, Pressur-
ization and Smoke Purge modes require the Controls Expan-
sion Board (CEM). The Fire Shutdown input is located on the
main board (MBB) on terminals TB5-10 and 11. The unit may
also be equipped with a factory-installed return air smoke de-
tector that is wired to TB5-10 and 11 and will shut the unit
down if a smoke condition is determined. Field-monitoring
wiring can be connected to terminal TB5-8 and 9 to monitor
the smoke detector. Inputs on the CEM board can be used to
put the unit in the Pressurization, Evacuation, and Smoke
Purge modes. These switches or inputs are connected to TB6 as
shown below. Refer to Major System Components section on
page 101 for wiring diagrams.
Pressurization — TB6-12 and 13
Evacuation — TB6-13 and 14
Smoke Purge — TB6-13 and 15
Each mode must be energized individually on discrete in-
puts and the corresponding alarm is initiated when a mode is
activated. The fire system provides a normally closed dry con-
tact closure. Multiple smoke control inputs, sensed by the con-
trol will force the unit into a Fire Shutdown mode.
FIRE-SMOKE INPUTS — These discrete inputs can be
found on the local display under
Inputs
FIRE
.
Fire Shutdown Mode — This mode will cause an immediate
and complete shutdown of the unit.
Pressurization Mode — This mode attempts to raise the pres-
sure of a space to prevent smoke infiltration from an adjacent
space. Opening the economizer (thereby closing the return air
damper), shutting down power exhaust and turning the indoor
fan on will increase pressure in the space.
Evacuation Mode — This mode attempts to lower the pres-
sure of the space to prevent infiltrating an adjacent space with
its smoke. Closing the economizer (thereby opening the return-
air damper), turning on the power exhaust and shutting down
the indoor fan decrease pressure in the space.
Smoke Purge Mode — This mode attempts to draw out
smoke from the space after the emergency condition. Opening
the economizer (thereby closing the return-air damper), turning
on both the power exhaust and indoor fan will evacuate smoke
and bring in fresh air.
AIRFLOW CONTROL DURING THE FIRE-SMOKE
MODES — All non-smoke related control outputs will get
shut down in the fire-smoke modes. Those related to airflow
will be controlled as explained below. The following matrix
specifies all actions the control shall undertake when each
mode occurs (outputs are forced internally with CCN priority
number 1 - “Fire”):
*“FSO” refers to the supply VFD fire speed override configurable
speed.
BP.MT
= 1 (4 motors)
PE.A
PE.B
PE.C
Power Exhaust Stage 0
OFF
OFF
OFF
Power Exhaust Stage 1
ON
OFF
OFF
Power Exhaust Stage 2
OFF
ON
OFF
Power Exhaust Stage 3
ON
ON
OFF
Power Exhaust Stage 4
ON
ON
ON
BP.MT
= 2 (6 motors)
PE.A
PE.B
PE.C
Power Exhaust Stage 0
OFF
OFF
OFF
Power Exhaust Stage 1
ON
OFF
OFF
Power Exhaust Stage 2
OFF
ON
OFF
Power Exhaust Stage 3
ON
ON
OFF
Power Exhaust Stage 4
ON
OFF
ON
Power Exhaust Stage 5
OFF
ON
ON
Power Exhaust Stage 6
ON
ON
ON
ITEM
EXPANSION
RANGE
CCN
POINT
WRITE
STATUS
FIRE
FIRE-SMOKE INPUTS
FSD
Fire Shutdown Input
ALRM/NORM FSD
forcible
PRES
Pressurization Input
ALRM/NORM PRES forcible
EVAC
Evacuation Input
ALRM/NORM EVAC forcible
PURG
Smoke Purge Input
ALRM/NORM PURG forcible
DEVICE
PRESSURIZATION PURGE EVACUATION
FIRE
SHUTDOWN
Economizer
100%
100%
0%
0%
Indoor Fan —
VFD
ON/FSO*
ON/FSO*
OFF
OFF
Power Exhaust
OFF
ON/FSO*
ON/FSO*
OFF
Heat Interlock
Relay
ON
ON
OFF
OFF
Summary of Contents for WEATHERMAKER 48/50AJ
Page 103: ...103 Fig 15 Typical Main Control Box Wiring Schematic 48 50AJ AK AW AY Units cont a48 8355 ...
Page 104: ...104 Fig 16 Typical Main Control Box Wiring Schematic 48 50A2 A3 A4 A5 Units a48 8355 ...
Page 105: ...105 TO NEXT PAGE Fig 17 Typical Auxiliary Control Box Wiring Schematic A48 7294 ...
Page 106: ...106 Fig 17 Typical Auxiliary Control Box Wiring Schematic cont a48 8356 ...
Page 107: ...107 Fig 18 Typical 2 Stage Gas Heat Wiring Schematic Size 051 and 060 Units Shown a48 8357 ...
Page 113: ...113 Fig 22 Typical Power Schematic 48 50A2 A3 A4 A5060 Unit Shown ...
Page 114: ...114 SW1 SW2 OR DEHUMIDIFY SWITCH Fig 23 Typical Controls Option Wiring Schematic a48 8361 ...
Page 115: ...115 Fig 24 Typical Small Chassis Component Location Size 020 035 Units a48 8362 ...
Page 116: ...116 Fig 25 Typical Large Chassis Component Locations Size 036 060 Units A48 7302 ...
Page 169: ...169 APPENDIX C VFD INFORMATION cont Fig F Internal Enclosure Fan Replacement A48 7716 ...