23
If space pressure decreases until PEDM position is reduced
to 10% of open position, PEDM2 will open, deenergizing fan
contactor PEC2 and auxiliary control relay PER, and shutting
off fan no. 2.
If BP is less than BPSP – BPSO for 4 to 6 minutes, with the
power exhaust damper at minimum position, the exhaust fan
will be turned off and the BPSR will be set to its minimum val-
ue. See Table 23.
NOTE: Power exhaust has a 2-minute minimum off-time to
minimize cycling.
Table 22 — Power Exhaust
Fan Operation Definitions
If the supply fan is off, then exhaust fan will be turned off
and BPSR set to minimum value. The exhaust fan is then off,
the discharge damper is closed, and the control input is set to 0.
Configuration
— To configure the modulating power exhaust,
Select Exhaust Fan Type. See Table 23.
To select the exhaust fan type, press to enter
into the Service function. Enter the password. Press to
enter into the Factory Configuration subfunction. Scroll down
to PWRX. The current configuration will be shown. Press
to set the configuration to modulating power exhaust.
The acceptable range of values is 0 to 2, where 0 is no fan, 1 is
non-modulating, and 2 is modulating.
To set the Building Pressure Set Point, press to en-
ter into the Service function. Enter the password. Press
to enter into the Building Pressure subfunction.
Scroll down to BPSP. The current pressure set point will be
shown in inches water gage. The default is 0.05 in. wg. The ac-
ceptable range of values is 0.00 to 0.50 in. wg. To change the
set point, enter the new number (ex. ) and press
.
To set the Building Pressure Set Point Offset, press
to enter into the Service function. Enter the password. Press
to enter into the Building Pressure subfunction.
Scroll down to BPSO. The current offset set point will be
shown in inches water gage. The default is 0.05 in. wg. The ac-
ceptable range of values is 0.05 to 0.50 in. wg. To change the
set point, enter the new number (example: ) and
press .
Table 23 — Configuring Modulating Power Exhaust
*If value changed, enable Data Reset before leaving .
ITEM DEFINITION
BP
Actual Space Pressure
BPSO
Building Pressure Set Point Offset
BPSP
Building Pressure Set Point
BPSR
Building Pressure Submaster Reference
EF
Discrete Output to Cycle Fan
ECON
Economizer Position
PED
Analog Damper/Inverter Output
PWRX
Power Exhaust Type
ENTER
ENTER
DESCRIPTION HOW TO CONFIGURE AT HSIO SET POINT RANGE
Select Exhaust Fan Type
FANT Modu Pow Exh = 2*
Select Building Pressure Set Point
BPSP
0.00 to 0.50 in. wg
(0.0 to 125 Pa)
Select Building Pressure Set Point Offset
BPSO
0.05 to 0.50 in. wg
(12 to 125 Pa)
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