Configurations - Trane UniTrane Installation, Operation And Maintenance Manual

Figure 55. Typical connection
Adjusting Optional Auto-Changeover
Function on CSTI Units
WARNING
Hazardous Voltage w/Capacitors!
Failure to disconnect power and discharge capacitors
before servicing could result in death or serious injury.
Disconnect all electric power, including remote
disconnects and discharge all motor start/run
capacitors before servicing. Follow proper lockout/
tagout procedures to ensure the power cannot be
inadvertently energized. For variable frequency drives or
other energy storing components provided by Trane or
others, refer to the appropriate manufacturer's literature
for allowable waiting periods for discharge of
capacitors. Verify with an appropriate voltmeter that all
capacitors have discharged.
For additional information regarding the safe discharge
of capacitors, see PROD-SVB06A-EN
The motor control board provides additional temperature
controlled logic to help coordinate certain electric-heat
and valve logic functions:
• On units with electric heat and a changeover coil, the
motor control board and adapter boards are pre-
configured to cause hydronic heat and electric heat to
be mutually exclusive:
– On units with ComfortLink™ controls (Tracer® ZN
controllers) or BacNet™ controls (UC400-B), the
Tracer® ZN controller board will serve as the
primary logic to select the electric heat only if hot
water is not available, but the motor control board
will service as a backup lockout.
– On units with Customer Supplied Controllers (CSTI
units), the motor control board and CSTI board will
serve as the primary lockout.
• On CSTI units selected with a changeover coil
configuration, the motor control board is factory
UNT-SVX07J-EN
configured to work in conjunction with the CSTI
adapter board to provide a useful auto-changeover
function. Traditionally, a fixed setpoint bi-metallic disc
temperature switch is used to provide changeover with
customer controls; however, the motor control board
has defeatable and configurable bi-metallic disc
temperature switch emulation when combined with
the CSTI adapter board. The motor control board is
pre-configured for typical values, so changeover
settings do not necessarily need to be changed.
Note: CSTI board does not support changeover function
with modulating valves.
– An NTC thermistor is supplied and affixed to the
supply pipes where applicable. The motor control
board has several settings that affect the operation
of the changeover function:
Fprv
• parameter should normally be set to
Ehfs
or to use the changeover functions.
Ehl
• parameter should be chosen if the unit has
a changeover coil without electric heat.
EhFs
• parameter should be chosen if the unit
has a changeover coil with electric heat.
Generally, this will perform the same as the
parameter but in addition, will disable heating
function on electric heat and on the changeover
coil if there are fan failures. The auxiliary heating
coil function will continue to operate and
respond to the customer heating request.
AiPU
• parameter should be set to
Out
and to for ComfortLink or BacNet controller units.
Ai2M
• parameter defines the temperature at which
the motor control board will close the triac onboard the
motor control board (if
correctly).
Ai2b
• parameter defines the temperature at which the
motor control board will open the triac onboard the
motor control board (if
correctly). By leaving a "gap" between the make and
break value, we will simulate hysteresis of a real bi-
metallic disc temperature switch.
• When combined with the CSTI adapter board, the bi-
metallic disc temperature switch emulation and the
electric heat lockout function will work when the
switches are set correctly.

Configurations

Every Trane unit with ECM motors will have modules
specifically configured at the factory for the operation of
that unit. The motor control board configuration label is
affixed to the low-voltage access lid on the outside of the
control panel (see Figure 45, p. 68
The VelociTach motor control board label may be on the
back-side of the low voltage access lid, depending on the
unit configuration.
ECM Overview and Setup
In
for CSTI units
Fprv
parameter is set
Fprv
parameter is set
and Figure 56, p.
EHl
Ehl
76).
75