Ingersoll-Rand Voyager TZ 150F Series Service Facts Download Page 18

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RT-SVF69C-EN

Sequence of Operation

Zone Temperature Control without

a Night Setback Panel or ICS - Unoccupied
Cooling

When a field supplied occupied/unoccupied switching
device is connected between RTRM J6-11 and RTRM J6-12,
both the economizer and the mechanical cooling will be
disabled.

Zone Temperature Control without

a Night Setback Panel or ICS - Unoccupied
Heating

When a field supplied occupied/unoccupied switching
device is connected between RTRM J6-11 and J6-12 and
DWU is enabled, the zone temperature will be controlled at
10°F below the Morning Warm-up setpoint, but not less
than 50°F, by cycling one or two stages of either gas or
electric heat, whichever is applicable.

Morning Warm-up (MWU) Control

Morning Warm-up is activated if the zone temperature is at
least 1.5°F below the MWU setpoint whenever the system
switches from Unoccupied to Occupied status. The MWU
setpoint may be set from the unit mounted potentiometer
or a remotely mounted potentiometer. The setpoint
ranges are from 50°F to 90°F. When the zone temperature
meets or exceeds the MWU setpoint, the unit will switch to
the “Cooling” mode. The economizer will be held closed
during the morning warm-up cycle.

Daytime Warm-up (DWU) Control

Daytime Warm-up is applicable during occupied status
and when the zone temperature is below the initiation
temperature. It can be activated or deactivated through
ICS or a night setback zone sensor. If ICS or a night setback
zone sensor is not utilized, DWU can be activated by
setting the DWU enable DIP switch (RTAM) to ON and
supplying a valid morning warm-up setpoint. The unit is
shipped with a Morning Warm-up setpoint configured and
the Daytime Warm-up function is activated (switch on).
Opening the DWU enable switch will disable this function.
If the system control is local, the DWU initiation setpoint is
3°F below the Morning Warm-up setpoint. The termination
setpoint is equal to the Morning Warm-up setpoint. If the
system control is remote (Tracer™), the DWU setpoint is
equal to the Tracer Occupied heating setpoint. The
initiation and termination setpoints are selectable
setpoints designated by Tracer. When the zone
temperature meets or exceeds the termination setpoint
while the unit is in an Occupied, “Auto” Mode or switched
to the “Cooling” Mode, the unit will revert to the cooling
operation. If an Occupied “Heating” Mode is selected, the
unit will only function within the DWU perimeters until the
system is switched from the “Heat” Mode or enters an
Unoccupied status.

Note:

When a LCI is installed on a VAV unit, the MWU
setpoint located on the RTAM board is ignored. The

MWU and DWU setpoints come from the higher
priority LCI-R DAC.

Supply Duct Static Pressure Control

The supply duct static pressure is measured by a
transducer with a 0.25 to 2.125 Vdc proportional output
which corresponds to an adjustable supply duct static
pressure of 0.3" w.c. to 2.5" w.c. respectively with a
deadband adjustment range from 0.2" w.c. to 1.0" w.c. The
setpoint is adjustable on the RTAM Static Pressure
Setpoint potentiometer or through ICS.

Example:

Supply Duct Static setpoint = 2.0" w.c. (RTAM)

Deadband = 0.2" w.c. (RTAM)

Duct Static Control Range = 1.9" w.c. to 2.1" w.c.

Mechanical Cooling with an Economizer

The economizer is utilized to control the zone temperature
when the outside air conditions are suitable. The method
used to determine economizer effectiveness, depending
on the available data, is described below in descending
order of complexity.

The most sophisticated method available is always used.
Two of the three methods for determining the suitability of
the outside air can be selected utilizing the potentiometer
on the Economizer Actuator, as described below:

Ambient Temperature - controlling the economizing
cycle by sensing the outside air dry bulb temperature.

Table 14. Variable air volume mode operation

System Mode

Fan “Auto”

Fan “On”

Heat

DWU Active
DWU Off

DWU

Off

DWU

VAV Heating

Cool