Configurations - Trane BCHE Installation, Operation And Maintenance Manual

Figure 97. 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 a CAT III or IV
voltmeter rated per NFPA 70E that all capacitors have
discharged.
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
controllers) or BACnet
®
Tracer ZN controller board will serve as the
BCX-SVX002A-EN
®
ZN
®
controls (UC400-B), the
ECM Overview and Setup
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
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
preconfigured for typical values, so changeover
settings do not necessarily need to be changed.
– 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:
• F F p p r r v v parameter should normally be set to E E H H l l
or E E h h f f s s to use the changeover functions.
• E E h h l l parameter should be chosen if the unit has
a changeover coil without electric heat.
• E E h h F F s s parameter should be chosen if the unit
has a changeover coil with electric heat.
Generally, this will perform the same as the E E h h l l
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.
• A A i i P P U U parameter should be set to In for C C S S T T I I units and
to Out for ComfortLink or BACnet controller units.
• A A i i 2 2 M M parameter defines the temperature at which the
motor control board will close the triac onboard the
motor control board (if F F p p r r v v parameter is set correctly).
• A A i i 2 2 b b parameter defines the temperature at which the
motor control board will open the triac onboard the
motor control board (if F F p p r r v v parameter is set 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. The VelociTach motor control board label
95