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SCXF-SVX01T-EN
Table 34. RTM resistance value vs. system operating
mode
Resistance applied to
RTM mode input
terminals, ohms
CV Units VAV Units
Fan mode
System
mode
System
mode
2320 auto off off
4870 auto cool
7680 auto auto auto
10,770
on off
13,320
on cool
16,130
on auto
19,480
auto heat
27,930
on heat
Note: Mode boundaries are 1000 to 40,000 ohms. Other boundaries are
equal to the midpoint between the nominal mode resistance.
Compressor Module
(MCM - Standard on all units)
The Compressor module, upon receiving a request for
mechanical cooling, energizes the appropriate
compressors and condenser fans. It monitors the
compressor operation through feedback information it
receives from various protection devices.
Human Interface Module—Standard on
all Units
The human interface (HI) module enables the operator to
adjust the operating parameters for the unit using its 16-key
keypad on the human interface panel. The HI panel
provides a two line, 40 character, clear language (English,
Spanish, or French) LCD screen with unit status
information and menus to set or modify operating
parameters. It is mounted in the unit’s main control panel
and accessible through the unit’s control panel door.
Remote Human Interface Module Option
The optional remote-mount human interface (RHI) panel
has all the functions of the unit-mounted version except for
service mode. To use a RHI, the unit must be equipped
with an optional interprocessor communications bridge
(IPCB). Model number digit 32 (=2) indicates if the ICPB
was ordered with the unit. If not, contact your local Trane
representative to order an ICPB kit for field installation. The
RHI can be located up to 1,000 feet (304.8 m) from the unit.
A single RHI can monitor and control up to four self-
contained units if each one contains an IPCB. The IPCB
switches must be set as SW1–off, SW2–off, and SW3–on.
Interprocessor Communications Board
(IPCB - Optional used with the Optional Remote Human
Interface)
The Interprocessor Communication Board expands
communications from the rooftop unit UCM network to a
Remote Human Interface Panel. DIP switch settings on the
IPCB module for this application should be; Switches 1 and
2 “Off”, Switch 3 “On”.
Waterside Module—Standard on All
Water-cooled Units
The waterside module (WSM) controls all water valves
based on unit configuration. In addition, the WSM monitors
waterflow proving and the following temperatures:
• Entering water
• Entering air low
• Mixed air
• Entering condenser water
• Refrigerant circuit 3:
– Saturated condenser
– Evaporator frost
• Refrigerant circuit 4:
– Condenser
– Evaporator
Cooling Tower Interlock
To interlock condenser pump/tower with cooling operation,
wire the cooling tower to an external 115 volt control power
source, to ground, and to control terminal block. Normally
open/closed contacts are provided.
Heat Module
The heat module is standard on all units with factory-
installed heat. It controls the unit heater to stage up and
down to bring the temperature in the controlled space to
within the applicable heating setpoint. Also, it includes a
freezestat, morning warm-up, and heating outputs.
Ventilation Override Module (VOM)
Option
The ventilation override module can be field-configured
with up to five different override sequences for ventilation
override control purpose. When any one of the module’s
five binary inputs are activated, it will initiate specified
functions such as: space pressurization, exhaust, purge,
purge with duct pressure control, and unit off.
Once the ventilation sequences are configured, they can
be changed unless they are locked using the HI. Once
locked, the ventilation sequences cannot be unlocked.
The compressors and condenser fans disable during the
ventilation operation. If more than one ventilation sequence
activates, the one with the highest priority (VOM “A”)
begins first, with VOM “E” having lowest priority and
beginning last.
A description of the VOM binary inputs follows below.
Controls
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