Carrier WEATHERMASTER 48/50Z030-105 - Manual (Page 70)

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BUILDING PRESSURE CONFIGURATION — The build-
ing pressure configurations are found at the local display under
Configuration → BP. See Table 58.
Building Pressure Config (BP.CF) — This configuration se-
lects the type of building pressure control.
• BP.CF = 0, No building pressure control
• BP.CF = 1, constant volume two-stage exhaust based on
economizer position
• BP.CF = 2, Modulating building pressure control based
on building pressure sensor
• BP.CF = 3, VFD controlling two exhaust fan motors
• BP.CF = 4, VFD control of one of the two exhaust fan
motors (sizes 075-105 with high-capacity exhaust option)
• BP.CF = 5, used on sizes 075-105 with return/exhaust
fan option
Building Pressure Sensor (BP.S) — This configuration al-
lows the reading of a building pressure sensor when enabled.
This is automatically enabled when BP.CF = 2, 3, 4 or 5.
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 sensors that measure both
positive and negative pressure.
Building Pressure SETP (BP.SP) — This set point is the
building pressure control set point. If the unit is configured for
a type of modulating building pressure control, then this is the
set point that the control will control to.
BP Setpoint Offset (BP.SO) — For building pressure config-
urations BP.CF=2, 3, and 4, this is the offset below the building
pressure set point that the building pressure must fall below to
turn off power exhaust control.
Power Exhaust on Setp.1 (BP.P1) — When configured for
building pressure control type BP.CF = 1 (constant volume
two-stage control), the control will turn on the first power
exhaust fan when the economizer’s position exceeds this set
point.
Power Exhaust on Setp.2 (BP.P2) — When configured for
building pressure control type BP.CF = 1 (constant volume
two-stage control), the control will turn on the second power
exhaust fan when the economizer’s position exceeds this set
point.
VFD/Act. Fire Speed/Pos (BP.FS) — For BP.CF = 2, 3, 4,
and 5, this configuration is the VFD speed position override
when the control is in the purge and evacuation smoke control
modes.
VFD/Act. Min Speed/Pos (BP.MN) — For BP.CF = 2, 3, 4,
and 5, this configuration is the minimum VFD speed/actuator
position during building pressure control.
VFD Maximum Speed/Pos (BP.MX) — For BP.CF = 3 and
5, this configuration is the maximum VFD speed during build-
ing pressure control.
BP 1 Actuator Max Pos. (BP.1M) — For BP.CF = 2, this
configuration is the maximum actuator no. 1 position during
building pressure control.
BP 2 Actuator Max Pos. (BP.2M) — For BP.CF = 2, this
configuration is the maximum actuator no. 2 position during
building pressure control.
BP Hi Cap VFD Clamp Val. (BP.CL) — For BP.CF = 4, this
configuration is a limit which creates a deadband which con-
trols the action of the second power exhaust relay.
Fan Track Learn Enable (FT.CF) — For BP.CF = 5, this
return/exhaust control configuration selects whether the fan
tracking algorithm will make corrections over time and add a
learned offset to FT.ST. If this configuration is set to No, the
unit will try to control the delta cfm value between the supply
and return VFDs only based on FT.ST.
Fan Track Learn Rate (FT.TM) — For BP.CF = 5, this return/
exhaust control configuration is a timer that affects corrections
to the delta cfm operation. The smaller this value, the more of-
ten corrections may be made based on building pressure error.
This configuration is only valid when FT.CF = Yes.
Fan Track Initial DCFM (FT.ST) — For BP.CF = 5, this
return/exhaust control configuration is the start point upon
which corrections (offset) are made over time when FT.CF =
Yes. It is the constant control point for delta cfm control when
FT.CF = No.
Fan Track Max Clamp (FT.MX) — For BP.CF = 5, this
return/exhaust control configuration is the maximum positive
delta cfm control value allowed unless outdoor air cfm control
is available and then the delta cfm control value would
be clamped to the outdoor air cfm value directly (see the
Economizer section for a description of outdoor air cfm
configuration).
Fan Track Max Correction (FT.AD) — For BP.CF = 5, this
return/exhaust control configuration is the maximum correc-
tion allowed every time a correction is made based on FT.TM.
This configuration is only valid when FT.CF = Yes.
Fan Track Internal EEPROM (FT.OF) — For BP.CF = 5,
this return/exhaust control internal EEPROM value is a learned
correction that is stored in non-volatile RAM and adds to the
offset when FT.CF = Yes. This value is stored once per day
after the first correction. This configuration is only valid when
FT.CF = Yes.
Fan Track Internal Ram (FT.RM) — For BP.CF = 5, this
return/exhaust control internal value is not a configuration but a
run time correction that adds to the offset throughout the day
when FT.CF = Yes. This value is only valid when FT.CF =
Yes.
Fan Track Reset Internal (FT.RS) — This option is a one
time reset of the internal RAM and internal EEPROM stored
offsets. If the system is not set up correctly and the offsets are
incorrect, this learned value can be reset.
Supply Air Cfm Config (SCF.C) — For BP.CF = 5, this con-
figuration is set at the factory depending on whether an air foil
or forward curve supply air fan is being used. This information
is then used by the control to determine the correct cfm tables
to be used when measuring supply air cfm.
Building Pressure Run Rate (BP.TM) — For BP.CF = 2,3,4,
and 5, this configuration is the PID run time rate.
Building Pressure Proportional Gain (BP.P) — For BP.CF =
2,3,4, and 5, this configuration is the PID Proportional Gain.
Building Pressure Integral Gain (BP.I) — For BP.CF =
2,3,4, and 5, this configuration is the PID Integral Gain.
Building Pressure Derivative Gain (BP.D) — For BP.CF =
2,3,4, and 5, this configuration is the PID Derivative Gain.
BUILDING PRESSURE CONTROL OPERATION
Configuration
→ BP → BP.CF = 1 (Constant Volume 2-Stage
Control) — Two exhaust fan relays will be turned on and off
based on economizer position to maintain building pressure
control. The two trip set points are Configuration →
BP → BP.P1 and Configuration → BP → BP.P2. If the economiz-
er position is greater than or equal to BP.P1, then power exhaust
relay 1 is energized, turning on the first stage. A 60-second tim-
er is initialized. If the economizer falls 5% below the BP.P1,
then the power exhaust fan relay is turned off. If the economizer
position is less than BP.P1 and the 60-second timer has expired,
the power exhaust fan relay is turned off. The same logic applies
to the second power exhaust fan relay, except the BP.P2 trip
point is monitored. If the economizer position is greater than or
equal to BP.P2, then power exhaust relay 2 is energized, turning
on the second stage. A 60-second timer is initialized. If the
economizer is 5% below the BP.P2 the second power exhaust
fan relay is turned off. If the economizer is less than BP.P2 and
the 60-second timer has expired, the power exhaust fan relay is
turned off.