Carrier WEATHERMASTER 48/50Z030-105 - Manual (Page 101)

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T316 (OAT Below Limit) — If the outside-air temperature
measured by the OAT thermistor (Temperatures → AIR.T →
OAT) is below the configurable OAT Low Alert Limit (Con-
figuration → ALLM → OAT.L) for 5 minutes then the alert will
be broadcast.
T317 (OAT Above Limit — If the outside-air temperature
measured by the OAT thermistor (Temperatures → AIR.T →
OAT) is above the configurable OAT High Alert Limit
(Configuration → ALLM → OAT.H) for 5 minutes then the alert
will be broadcast.
A400 (Hydronic Freezestat Trip) — If the freezestat for the
hydronic coil trips, the unit goes into emergency mode and
does not allow cooling or heating. The economizer goes to 0%
open. Supply fan operation is enabled. Recovery is automatic
when the switch goes off.
A404 (Fire Shut Down Emergency Mode [fire-smoke]) —
If the fire shutdown input is energized (fire shutdown is in ef-
fect), or if two fire smoke modes are incorrectly energized at
the same time, a Fire Shutdown mode will occur. This is an
emergency mode requiring the complete shutdown of the unit.
Recovery is automatic when the inputs are no longer on.
A405 (Evacuation Emergency Mode) — If the evacuation in-
put on the CEM is energized, an evacuation mode occurs
which flags an alarm. This mode attempts to lower the pressure
of the space to prevent smoke from moving into another space.
This is the reverse of the Pressurization Mode. Closing the
economizer, opening the return-air damper, turning on the
power exhaust, and shutting down the indoor fan will decrease
pressure in the space. Recovery is automatic when the input is
no longer on.
A406 (Pressurization Emergency Mode) — If the pressuriza-
tion input on the CEM is energized, a pressurization mode
occurs which flags an alarm. This mode attempts to raise the
pressure of a space to prevent smoke infiltration from another
space. The space with smoke should be in an Evacuation Mode
attempting to lower its pressure. Opening the economizer, clos-
ing the return air damper, shutting down power exhaust, and
turning the indoor fan on will increase pressure in the space.
Recovery is automatic when the input is no longer on.
A407 (Smoke Purge Emergency Mode) — If the smoke
purge input on the CEM is energized, a smoke purge mode
occurs which flags an alarm. This mode attempts to draw out
smoke from the space after the emergency condition. Opening
the economizer, closing the return-air damper, and turning on
both the power exhaust and indoor fan will evacuate smoke
and bring in fresh air. Recovery is automatic when the input is
no longer on.
T408 (Dirty Air Filter) — If no dirty filter switch is installed,
the switch will read “clean filter” all the time. Therefore the
dirty filter routine runs continuously and diagnoses the input.
Because of the different possible times it takes to generate
static pressure, this routine waits 2 minutes after the fan starts
before the dirty filter switch is monitored. If the dirty filter
switch reads “dirty filter” for 2 continuous minutes, an alert is
generated. No system action is taken. This is a reminder that it
is time to change the filters in the unit. Recovery from this alert
is through a clearing of all alarms (manual) or after the dirty fil-
ter switch reads clean for 30 continuous seconds (automatic).
T409 (Supply Fan Commanded On, Sensed Off Failure)
T409 (Supply Fan Commanded Off, Sensed On Failure)
A409 (Supply Fan Commanded On, Sensed Off Failure)
A409 (Supply Fan Commanded Off, Sensed On Failure) —
Both the alert and the alarm refer to the same failure. The only
difference between the alarm and alert is that in the case where
the supply fan status configuration to shut down the unit is set
to YES (Configuration → UNIT → SFS.S), the alarm will be
generated AND the unit will be shut down. It is possible to
configure Configuration → UNIT → SFS.M to either a switch
or to monitor a 0.2-in. wg rise in duct pressure if the unit is
VAV with duct pressure control (IGV or VFD).
The timings for failure for both are the same and are illus-
trated in the following table:
Recovery is manual. Reason for failure may be a broken fan
belt, failed fan relay or failed supply fan status switch.
T421 (Thermostat Y2 Input On without Y1 On) — If Y2 is
on and Y1 is off then this alert condition is initiated. The
control continues as if both Y1 and Y2 were requested. Alert
recovery will not occur until Y1 is seen. This handles some
conditions of an incorrectly wired thermostat and may prevent
multiple alerts and recoveries from clogging the alarm
histories.
T422 (Thermostat W2 Input On without W1 On) — If W2
is on and W1 is off then this alert condition is initiated.
The control continues as if both W1 and W2 were requested.
Alert recovery will not occur until W1 is seen. This handles
some conditions of an incorrectly wired thermostat and may
prevent multiple alerts and recoveries from clogging the alarm
histories.
T423 (Thermostat Y and W Inputs On) — Simultaneous calls
for heating and cooling are illegal and will be alarmed. Cooling
and heating will be locked out. Recovery is automatic when the
condition no longer exists.
T424 (Thermostat G Input Off On a Cooling Call) — If G is
off and there is a cooling request (Y1 or Y2), then it is possible
the G connection has not been made to the unit terminal block.
An alert is initiated for this condition as continuous fan opera-
tion and manual fan control may not be possible. Cooling is
started, if allowed, and the fan is turned on. The controls do not
diagnose the fan if a heat request (W1 or W2) is in progress.
T430 (Plenum Pressure Safety Switch Trip)
A430 (Plenum Pressure Safety Switch Trip) — If the unit is
configured for fan tracking and the plenum pressure switch
trips, the unit will be instructed to shut down immediately. The
first 2 times the switch trips, the unit will automatically start up
and clear the alert 3 minutes after the switch recovers. The third
time the switch trips, the unit shuts down and calls out the
alarm. Manual reset of the switch (located in the auxiliary con-
trol panel) is required. Software reset is automatic when switch
has been reset. Possible causes are blocked exhaust or return
dampers causing high pressure at the plenum fan.
T500 (Current Sensor Board Failure - A1)
T501 (Current Sensor Board Failure - A2)
T502 (Current Sensor Board Failure - B1)
T503 (Current Sensor Board Failure - B2)
NOTE: These alerts are only applicable to size 105 units.
If the current sensor board malfunctions or is not properly
connected to its assigned digital input, an alert will be generat-
ed. It takes 2 to 4 seconds to log the alert. If the alert is logged,
it stays active for a minimum of 15 seconds to provide the ap-
plication a reasonable time to catch the failure. Compressors
will be not be inhibited by this failure. Recovery is automatic.
Reason for failure may be a faulty current sensor board, incor-
rect wiring, or a damaged input on the MBB control board.
UNIT TYPE/MODE MINIMUM ON
TIME WAIT MINIMUM OFF
TIME WAIT
CV (no gas heat) 30 seconds 1 minute
CV (gas heat) 2 minutes 4 minutes
VAV (IGV/no gas heat) 2 minutes 4 minutes
VAV (VFD/no gas heat) 1 minute 1 minute
VAV (IGV/gas heat) 4 minutes 4 minutes
VAV (VFD/gas heat) 3 minutes 4 minutes