75
Table 62 — Static Pressure Reset Related Points
Table 63 — Fan Status Monitoring Configuration
Fan Fail Shuts Down Unit (SFS.S)
This configuration will configure the unit to shut down on a sup-
ply fan status fail or simply alert the condition and continue to run.
When configured to YES, the control will shut down the unit if
supply fan status monitoring fails and send out an alarm. If set to
no, the control will not shut down the unit if supply fan status
monitoring fails but will send out an alert.
SUPPLY FAN STATUS MONITORING LOGIC
Regardless of whether the user is monitoring a discrete switch or
is monitoring static pressure, the timings for both techniques are
the same and rely upon the configuration of static pressure control.
The configuration that determines static pressure control is Con-
figuration
SP
SP.CF. If this configuration is set to 0 (none), a
fan failure condition must wait 60 continuous seconds before tak-
ing action. If this configuration is 1 (VFD), a fan failure condition
must wait 3 continuous minutes before taking action.
If the unit is configured to monitor a fan status switch (SFS.M =
1), and if the supply fan commanded state does not match the sup-
ply fan status switch for 3 continuous minutes, then a fan status
failure has occurred.
If the unit is configured for supply duct pressure monitoring
(SFS.M = 2), then
• If the supply fan is requested ON and the static pressure
reading is not greater than 0.2 in. wg for 3 continuous min-
utes, a fan failure has occurred.
• If the supply fan is requested OFF and the static pressure
reading is not less than 0.2 in. wg for 3 continuous minutes,
a fan failure has occurred.
Dirty Filter Switch
The unit can be equipped with a field-installed accessory dirty fil-
ter switch. The switch is located in the filter section. If a dirty filter
switch is not installed, the switch input is configured to read
“clean” all the time.
To enable sensor for dirty filter monitoring, set Configuration
UNIT
SENS
FLT.S to ENABLE. The state of the filter status
switch can be read at Inputs
GEN.I
FLT.S. See Table 64.
Table 64 — Dirty Filter Switch Points
Monitoring of the filter status switch is disabled in the Service Test
mode and when the supply fan is not commanded on. If the fan is
on and the unit is not in a test mode and the filter status switch
reads “dirty” for 2 continuous minutes, an alert is generated. Re-
covery from this alert is done through a clearing of all alarms or
after cleaning the filter and the switch reads “clean” for
30 seconds.
NOTE: The filter switch should be adjusted to allow for the oper-
ating cfm and the type of filter. Refer to the accessory installation
instructions for information on adjusting the switch.
Economizer
The economizer control is used to manage the outside and return
air dampers of the unit to provide ventilation air as well as free
cooling based on several configuration options. This section con-
tains a description of the economizer and its ability to provide free
cooling. See the Indoor Air Quality section on page 87 for more
information on setting up and using the economizer to perform de-
mand controlled ventilation (DCV). See the third-party Control
section on page 42 for a description on how to take over the opera-
tion of the economizer through external control.
The economizer system also permits unit to perform smoke con-
trol functions based on external control switch inputs. Refer to the
Smoke Control Modes section on page 87 for detailed discussions.
Economizer control can be based on automatic control algorithms
using unit-based set points and sensor inputs. This economizer
control system can also be managed through external logic
systems.
The economizer system is a factory-installed option. This option
includes a factory-installed enthalpy control device to determine
the changeover condition that permits free cooling operation. This
unit can also have the following devices installed to enhance econ-
omizer control:
• Outside air humidity sensor
• Return air humidity sensor
• Outside airflow control
NOTE: All these options require the CEM.
The P Series economizer damper is managed by a communicating
actuator motor(s). This provides the ability of the control system
to monitor, diagnose, and report the health and operation of the ac-
tuator and damper system to the local display and CCN network,
thus providing extensive diagnostic tools to servicers.
ECONOMIZER FAULT DETECTION AND DIAGNOSTICS
(FDD) CONTROL
The Economizer Fault Detection and Diagnostics control can be
divided into two tests: test for mechanically disconnected actuator
and test for stuck/jammed actuator.
Mechanically Disconnected Actuator
The test for a mechanically disconnected actuator is performed by
monitoring SAT as the actuator position changes and the damper
blades modulate. As the damper opens, it is expected SAT will
drop and approach OAT when the damper is at 100%. As the
damper closes, it is expected SAT will rise and approach RAT
when the damper is at 0%. The basic test is as follows:
1. With supply fan running take a sample of SAT at current
actuator position.
2. Modulate actuator to new position.
3. Allow time for SAT to stabilize at new position.
4. Take sample of SAT at new actuator position and determine:
a. If damper has opened, SAT should have decreased.
b. If damper has closed, SAT should have increased.
ITEM EXPANSION RANGE UNITS CCN POINT DEFAULT
Inputs
4-20
SP.M Static Pressure mA 4 to 20 mA SP_MA
4-20
SP.M.T Static Pressure mA Trim –2.0 to +2.0 mA SPMATRIM
4-20
SP.R.M Static Pressure Reset mA 4 to 20 mA SPRST_MA 0.0
RSET
SP.RS Static Pressure Reset 0.0 to 3.0 in. wg SPRESET 0.0
Outputs
FANS
S.VFD Supply Fan VFD Speed 0 to 100 % SFAN_VFD
ITEM EXPANSION RANGE CCN POINT
SFS.S Fan Fail Shuts Down Unit Yes/No SFS_SHUT
SFS.M Fan Stat Monitoring Type 0 to 2 SFS_MON
ITEM EXPANSION RANGE CCN POINT
Configuration
UNIT
SENS
FLT.S
Filter Stat.Sw.Enabled? Enable/Disable FLTS_ENA
Inputs
GEN.I
FLT.S Filter Status Input DRTY/CLN FLTS
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