Carrier 48/50Z030-105

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.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.P1 and Configuration

→

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.