72
Static Pressure mA (SP.M)
This variable reflects the value of the static pressure sensor sig-
nal received by the
Comfort
Link controls. It may in some cases
be helpful in troubleshooting.
Static Pressure mA Trim (SP.M.T)
This input allows a modest amount of trim to the 4 to 20 mA
static pressure transducer signal, and can be used to calibrate a
transducer.
Static Pressure Reset mA (SP.R.M)
This input reflects the value of a 4 to 20 mA static pressure re-
set signal applied to TB202 terminals 6 and 7, from a third par-
ty control system.
Static Pressure Reset (SP.RS)
This variable reflects the value of a static pressure reset signal
applied from a CCN system. The means of applying this reset
is by forcing the value of the variable SPRESET through CCN.
Supply Fan VFD Speed (S.VFD)
This output can be used to check on the actual speed of the
VFD. This may be helpful in some cases for troubleshooting.
Fan Status Monitoring
GENERAL
The P Series
Comfort
Link controls offer the capability to de-
tect a failed supply fan through either a duct static pressure
transducer or an accessory discrete switch. The fan status
switch accessory (part no. CRFANSTATUS001A00) allows for
the discrete monitoring of the ON/OFF status of the unit supply
fan. The switch closes when the delta pressure across the
switch rises above a configurable threshold value. The switch
connects to plug PL34, which is located in the supply fan com-
partment. See Carrier accessory literature for more details. For
any unit with a factory-installed duct static pressure sensor, it is
possible to measure duct pressure rise directly, which removes
the need for a differential switch. Any unit with an installed
supply fan VFD will have the duct static pressure sensor as
standard.
SETTING UP THE SYSTEM
The fan status monitoring configurations are located in
Config-
uration
UNIT
.
See Table 61.
Table 61 — Fan Status Monitoring Configuration
Fan Stat Monitoring Type (SFS.M)
This configuration selects the type of fan status monitoring to
be performed.
0 - NONE — No switch or monitoring
1 - SWITCH — Use of the fan status switch
2 - SP RISE — Monitoring of the supply duct pressure.
Fan Fail Shuts Down Unit (SFS.S)
This configuration will configure the unit to shut down on a
supply 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 con-
trol is
Configuration
SP
SP.CF
.
If this configuration is set
to 0 (none), a fan failure condition must wait 60 continuous
seconds before taking 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
supply 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
filter 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 the sensor for dirty filter monitoring, set
Configura-
tion
UNIT
SENS
FLT.S
to ENABLE. The state of the
filter status switch can be read at
Inputs
GEN.I
FLT.S
. See
Table 62.
Table 62 — 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 sta-
tus switch reads “dirty” for 2 continuous minutes, an alert is
generated. Recovery 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 re-
turn air dampers of the unit to provide ventilation air as well as
free cooling based on several configuration options. This sec-
tion contains a description of the economizer and its ability to
provide free cooling. See the Indoor Air Quality section on
page 84 for more information on setting up and using the econ-
omizer to perform demand controlled ventilation (DCV). See
the Third Party Control section on page 39 for a description on
how to take over the operation of the economizer through ex-
ternal control.
The economizer system also permits this unit to perform
smoke control functions based on external control switch in-
puts. Refer to the Smoke Control Modes section on page 83 for
detailed discussions.
Economizer control can be based on automatic control algo-
rithms using unit-based set points and sensor inputs. This econ-
omizer control system can also be managed through external
logic systems.
The economizer system is a factory-installed option. This op-
tion includes a factory-installed enthalpy control device to de-
termine the changeover condition that permits free cooling op-
eration. This unit can also have the following devices installed
to enhance economizer control:
• Outside air humidity sensor
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
Summary of Contents for Weathermaster 48P2030-100
Page 130: ...130 Fig 19 Typical Power Schematic Sizes 040 075 Shown ...
Page 131: ...131 Fig 20 Main Base Board Input Output Connections ...
Page 132: ...132 Fig 21 RXB EXB CEM SCB Input Output Connections ...
Page 133: ...133 Fig 22 Typical Gas Heat Unit Control Wiring 48P030 100 Units Shown ...
Page 134: ...134 Fig 23 Typical Electric Heat Wiring 50P030 100 Units Shown ...
Page 135: ...135 Fig 24 Typical Power Wiring 115 V ...
Page 136: ...136 Fig 25 Typical Gas Heat Section Size 030 050 Units Shown ...
Page 138: ...138 Fig 27 Component Arrangement Size 030 035 Units ...
Page 139: ...139 Fig 28 Component Arrangement Size 040 075 Units ...
Page 140: ...140 Fig 29 Component Arrangement Size 090 100 Units ...
