Supply Duct Static Pressure Control; Modes Of Operation - Trane ReliaTel Diagnostic Manual

Unit functions are determined by the inputs on RTRM J6 as follows. The possible inputs are shown
in the top (horizontal) row. The functions available are shown in the vertical columns below each
input.
Table 48. VAV Default Mode Input
Occupied Cooling
Daytime Warm-up
Morning Warm-up
Indoor Blower
(occupied mode)
Indoor Blower
(unoccupied mode)
Unoccupied Cooling
Unoccupied Heating
Short Across RTRM J6-
11&12 creates an
unoccupied mode
(Night setback)
Note: * Means 'B' or 'C'

Supply Duct Static Pressure Control

The supply duct static pressure is measured by using a 0 to 5VDC transducer. The transducer is
mounted on the supply fan bulkhead on the motor side of the supply fan section. The transducer
is comparing the supply duct pressure (actually the pressure of the heat section of the unit) to
outdoor air pressure. The high port of the transducer is connected to the static pressure sensing
cover plate located on the supply fan bulkhead. The low port of the transducer is connected to a
tubing connector on a vertical support of the unit and is field-connected to the Outside Air Pressure
Sensor as pictured below. The transducer is wired to the RTAM and the decision to modulate the
IGV or VFD is made at the RTRM.

Modes of Operation

Setpoints are provided by using the potentiometers on the RTAM, through remote potentiometers,
or through ICS. The setpoint range is 0.3" WC to 2.5" WC. The deadband range is 0.2" WC to 1.0" WC.
The control band is the setpoint plus or minus ½ of the deadband.
For example:
Setpoint 1.5"
Deadband 0.4"
The IGV or VFD output will increase if the supply pressure goes below 1.3".
The IGV or VFD output will decrease if the supply pressure goes above 1.7"
The IGV or VFD output will not change if the supply pressure stays between 1.3" and 1.7".
DIP switch settings for this function are as follows:
RTAM SW1 switch 1 OFF for IGV, ON for VFD.
RTAM SW1 switch 2 OFF for VAV, ON for "VAV without IGV".
RT-SVD03G-EN
No Inputs Jumper
on RTRM RTRM J6- BAYSENS077A w/
J6 2&4 RTRM J6-2&4 Jumper
No Yes
No No
No No
Off On
N/A Off
N/A No
N/A No
No No
Voyager Commercial 27½ to 50 Tons CV and VAV
BAYSENS021* or
BAYSENS077A w/
7.68k resistor
between RTRM J6-2&4
Yes
Yes
Yes
On
Auto Auto
No
Yes
Yes
BAYSENS020* or ICS™
system (Tracer
Summit)
Yes Yes
Yes Yes
Yes Yes
On On
Auto
No Yes
Yes Yes
Yes N/A
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