66
Building Pressure Control
The building pressure control sequence provides control of pres-
sure in the building through the modulating flow rate function of
the modulating power exhaust option. This function also provides
control of the constant volume 2-stage power exhaust option.
BUILDING PRESSURE CONFIGURATION
The building pressure configurations are found at the local dis-
play under Configuration
BP. See Table 65.
Building Pressure Config (BP.CF)
This configuration selects the type of building pressure control.
• BP.CF = 0, No building pressure control
• BP.CF = 1, constant volume two-stage power exhaust
based on economizer position
• BP.CF = 2, multiple stage building pressure control based
on a building pressure sensor
• BP.CF = 3, VFD building pressure control based on a
building pressure sensor
Building Pressure PID Run Rate (BP.RT)
This configuration selects the run time of the PID algorithm.
This configuration is only active when BP.CF = 3. It is recom-
mended that this value not be changed without guidance from
Service Engineering.
Building Pressure Proportional Gain (BP.P)
This configuration selects the proportional gain of the PID al-
gorithm. This configuration is only active when BP.CF = 3. It
is recommended that this value not be changed without guid-
ance from Service Engineering.
Building Pressure Integral Gain (BP.I)
This configuration selects the integral gain of the PID algo-
rithm. This configuration is only active when BP.CF = 3. It is
recommended that this value not be changed without guidance
from Service Engineering.
Building Pressure Derivative Gain (BP.D)
This configuration selects the derivative gain of the PID algo-
rithm. This configuration is only active when BP.CF = 3. It is
recommended that this value not be changed without guidance
from Service Engineering.
Building Pressure Setpoint Offset (BP.SO)
This configuration is the value below the building pressure set-
point to which the building pressure must fall in order to turn
off power exhaust control. This configuration is only active
when BP.CF = 3.
Building Pressure Minimum Speed (BP.MN)
This configuration is the minimum allowed VFD speed during
building pressure control. This configuration is only active
when BP.CF = 3.
Building Pressure Maximum Speed (BP.MX)
This configuration is the maximum allowed VFD speed during
building pressure control. This configuration is only active
when BP.CF = 3.
VFD Fire Speed (BP.FS)
This configuration is the VFD speed override when the control
is in the purge or evacuation smoke control modes. This con-
figuration is only active when BP.CF = 3.
Power Exhaust Motors (BP.MT)
This configuration is machine dependent and instructs the
building pressure control algorithm whether the unit has 4 or 6
motors to control. The motors are controlled by three power
exhaust relays A, B, and C. These relay outputs are located at
the local display under Outputs
FANS
PE.A,B,C.
The following table illustrates the number of motors each relay
is in control of based on BP.MT:
Building Pressure Sensor (BP.S)
This configuration allows the reading of a building pressure
sensor when enabled. This is automatically enabled when
BP.CF = 2 or 3.
Building Pressure (+/–) Range (BP.R)
This configuration establishes the range in in. wg that a 4 to
20 mA sensor will be scaled to. The control only allows sen-
sors that measure both positive and negative pressure.
Table 65 — Building Pressure Configuration
*Some configurations are machine dependent.
BP.MT PE_A Relay PE_B Relay PE_C Relay
1 (4 motors) 1 Motor 2 Motors 1 Motor
2 (6 motors) 1 Motor 2 Motors 3 Motors
ITEM EXPANSION RANGE UNITS CCN POINT DEFAULT
BP BUILDING PRESS. CONFIG
BP.CF Building Press. Config 0 to 3 BLDG_CFG 0*
BP.RT Bldg.Pres.PID Run Rate 5 to 120 sec BPIDRATE 10
BP.P Bldg. Press. Prop. Gain 0 to 5 BLDGP_PG 0.5
BP.I Bldg.Press.Integ.Gain 0 to 2 BLDGP_IG 0.5
BP.D Bldg.Press.Deriv.Gain 0 to 5 BLDGP_DG 0.3
BP.SO BP Setpoint Offset 0.0 to 0.5 " H2O BPSO 0.05
BP.MN BP VFD Minimum Speed 0 to 100 % BLDGPMIN 10
BP.MX BP VFD Maximum Speed 0 to 100 % BLDGPMAX 100
BP.FS VFD/Act. Fire Speed/Pos. 0 to 100 % BLDGPFSO 100
BP.MT Power Exhaust Motors 1 to 2 PWRM 1*
BP.S Building Pressure Sensor Enable/Dsable BPSENS Dsable*
BP.R Bldg Press (+/–) Range 0 to 1.00 " H2O BP_RANGE 0.25
BP.SP Building Pressure Setp. -0.25 -> 0.25 " H2O BPSP 0.05
BP.P1 Power Exhaust On Setp.1 0 to 100 % PES1 35
BP.P2 Power Exhaust On Setp.2 0 to 100 % PES2 75
B.CFG BP ALGORITHM CONFIGS
BP.SL Modulating PE Alg. Slct. 1 to 3 BPSELECT 1
BP.TM BP PID Evaluation Time 0 to 10 min BPPERIOD 1
BP.ZG BP Threshold Adjustment 0.1 to 10.0 " H2O BPZ_GAIN 1
BP.HP High BP Level 0 to 1.000 " H2O BPHPLVL 0.05
BP.LP Low BP Level 0 to 1.000 " H2O BPLPLVL 0.04
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