Startup
50
RT-SVX34F-EN
VAV with modulating heat, the fan will be energized with
the call for heating in order to begin circulating airflow
through the unit for discharge air temperature control.
Once the call for heating is removed, the fan will remain on
for approximately 90 seconds.
Electric Heat Control
The RTRM provides two heating outputs for 1st and 2nd
stages that will be controlled with at least a 10 seconds
delay between each stage. When the fan selection switch
is in the “AUTO” mode and the unit is configured for
Constant Volume, the fan will start approximately 1
second before the 1
st
heater stage is activated. The fan and
heater will cycle off after the heating setpoint has been
satisfied. If the unit is configured for SZ VAV control, the
Supply Fan will energize approximately 5 seconds prior to
energizing the electric heat outputs. Once the Zone
Heating requirements have been satisfied, the fan and
heat outputs will be controlled off.
Clogged Filter Option
The unit mounted clogged filter switch monitors the
pressure differential across the return air filters. It is
mounted in the filter section and is connected to the
RTOM. The switch is adjustable and can be set for a
particular application. The clogged filter switch is normally
open and will automatically close when the pressure
differential across the filters falls below the clogged filter
setpoint. The RTOM will generate a SERVICE diagnostic
that will be sent to the zone sensor or remote panel when
the clogged filter switch has been closed for at least 2
minutes during supply fan operation. The system will
continue to operate regardless of the status of the clogged
filter switch.
Ventilation Override
Note:
Applying 24 volts to one of the three Ventilation
Override Inputs manually activates ventilation
override. One input is provided to request the
Pressurize Mode, the second input the Purge Mode,
and the third input the Exhaust Mode.
When the Pressurize Mode is selected, activating
Ventilation Override will cause the supply fan to run, the
economizer to open to 100%, the exhaust fan to turn
(remain) off, or the VFD to run at full speed (SZ VAV and
Traditional VAV), and the VAV boxes to fully open.
When Purge is selected, activating Ventilation Override
will cause the supply fan to run, the economizer to open to
100%, the exhaust fan to run, or the VFD to run at full speed
(SZ VAV or Traditional VAV), and the VAV boxes to fully
open.
When Exhaust is selected, activating Ventilation Override
will cause the supply fan to turn off, the economizer to
close to 0%, the exhaust fan to run (exhaust damper at
100% if configured for Statitrac), or the VFD to stop, and
the VAV boxes to operate normally.
If more than one mode is requested at the same time, the
Pressurize request will have priority followed by Purge.
When any Ventilation Override Mode is active, all heating
and cooling is turned off. For the case where the unit is
required to turn off, the Emergency Stop input is used. The
ICS can also initiate any ventilation override mode.
Table 26
lists the sequence of events within the system for
each ventilation mode. Refer to the unit wiring diagram for
contact switching and wiring.
Note:
Fresh air tracking will not work with VOM.
Emergency Stop
When this binary input is opened, all outputs are
immediately turned off and the system will not be allowed
to restart until the binary input is closed for approximately
5 seconds minimum. The shut down is communicated to
Tracer™ if applicable and the Heat and Cool LED outputs
(RTRM J6-7 and J6-8) will blink at a nominal rate of 1 blink
per second.
Phase Monitor
The Phase Monitor is a 3 phase line monitor module that
protects against phase loss, phase reversal and phase
unbalance. It is intended to protect compressors from
reverse rotation. It has an operating input voltage range of
190-600 VAC, and LED indicators for ON and FAULT. There
are no field adjustments and the module will automatically
reset from a fault condition.
Table 26. Ventilation override sequence
Mode and Priority
Affected
Function
Pressurize
Purge
Exhaust
(a)
(a) Exhaust mode 3 is not available with the tracking power exhaust
option.
1
2
3
Heat/Cool
off
off
off
VFD
full speed
full speed
full speed
Supply Fan
on
on
off
Exhaust Fan
off
on
(b)
(b) For units configured with the Statitrac option, the Exhaust Damper
will open during Ventilation Override modes that request the ex-
haust fan to operate.
on
Economizer
open
open
closed
VAV Boxes
forced open
forced open
normal
operation
