125
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.
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.
A410 (Supply Fan VFD Fault)
— The MBB has received a
fault status from the supply fan VFD. The unit will be shut
down, and a manual reset is required. The VFD keypad will in-
dicate which fault has occurred. Reset can be done at the unit
control (Alarms
R.CUR) or the VFD keypad.
A411 (Exhaust Fan VFD Fault)
— The MBB has received a
fault status from the exhaust fan VFD. Building pressure con-
trol will be stopped and a manual reset is required. The VFD
keypad will indicate which fault has occurred. Reset can be
done at the unit control (Alarms
R.CUR) or the VFD keypad.
T412 (Dirty Post Air Filter)
— If no dirty post filter switch is
installed, the switch will read "clean filter" all the time. There-
fore the dirty post filter routine runs continuously and diagno-
ses 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 post filter switch is monitored. If the
dirty post filter switch reads "dirty filter" for 2 continuous min-
utes, an alert is generated. No system action is taken. This is a
reminder that it is time to change the post filters in the unit. Re-
covery from this alert is through a clearing of all alarms (manu-
al) or after the dirty post filter switch reads clean for 30 contin-
uous seconds (automatic).
T413 (Air Pressure Switch Failure)
— If the air pressure
switch trips, the unit will be instructed to shut down immedi-
ately. Manual reset of the switch is required. Software reset is
automatic when switch has been reset. Possible causes are
blocked outlets on the building discharge duct, or the duct pres-
sure control system (i.e., duct pressure transducer, VFD, supply
fan) has failed.
T414 (UV-C Lamp Failure)
— If the unit is configured for
UV-C lamps with status monitoring (Configura-
tion
UNIT
UVC.L = ENAB W/ STS), this alert will be
logged when the UV-C lamp status input (In-
puts
GEN.I
UVC.S) does not equal the UV-C lamp output
(Outputs
GEN.O
UVC.L). Recovery is automatic. Possible
causes are UV-C lamp miswiring or UV-C lamp failure.
T415 (Damper Not Modulating)
— This alert occurs when the
supply air temperature does not change as expected when the
damper if moved. Check to determine if the damper is no longer
mechanically connected to the actuator. Reset is manual.
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.
T431 (Power Exhaust Motor Starter Protector Trip)
A432 (Power Exhaust Motor Starter Protector Lock) — If
the unit is configured for VFD power exhaust (BP.CF=3), the
unit monitors the status of the 2 power exhaust motor starter
protectors in the power leads between the PE VFD and the PE
Motors. If either one of the motor starter protectors trip, the
alert, T431, will be broadcast. The Building Pressure routine
will continue to operate but with only one power exhaust fan.
Depending on the operating conditions, the unit may not be
able to maintain the desired building pressure.
If both of the motor starter protectors trip, the alert, A432,
will be broadcast and the Building Pressure Control routine
will shut down. Possible causes are overloading of the power
exhaust motor(s) or wrong setting for the motor starter protec-
tor(s). Software reset is automatic when the switch(es) have
been reset.
T433 (3-Phase Power Failure)
— If the unit is configured for
power monitoring (Configuration
UNIT
PW.MN = YES),
if the power monitor input trips (Inputs
GEN.I
PWR.F =
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 (no gas heat) 1 minute 1 minute
VAV (gas heat) 3 minutes 4 minutes
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