Circuit Module Replacement - Trane BCHE Installation, Operation And Maintenance Manual

to the motor or the adapter boards while the power is
ON.
• Caution should be taken to stay clear of hazardous
voltages, moving parts and electric heat elements while
making adjustments to the VelociTach motor control
board. If it is not practical to stay clear of these areas
during adjustment, please contact Trane Global Parts
for configuration kit that allows easy powering of the
engine board outside of the unit with a 9V battery.
• For safe operation, it is necessary to configure
replacement boards to match the setup/switch
configuration of the previously installed boards.
• Ensure that new circuit modules are firmly seated on
the nylon standoffs, and that the nylon standoffs are
firmly seated on the metal panel
• Ensure that drip-loops are maintained on wiring on pipe
end of unit to avoid wicking of water into the unit.
• Before assuming that any of the boards or components
in the new system have failed, please ensure that the
VelociTach motor control board has been configured
correctly and that the switches on the CSTI board
(where applicable) are set correctly.
• It is necessary to configure the service replacement
VelociTach motor control board before commissioning
the unit. The board is pre-configured with safe values,
but will NOT work correctly unless properly configured.
The factory shipped parameter settings are on the label
adjacent to the VelociTach.
• Only genuine Trane replacement components with
identical Trane part numbers should be used.
• Unit fan assemblies contain concealed wires that
should be removed before the fan-board is removed, to
avoid nicking the wire.
• Care should be maintained to retain the order of the
motors with respect to the motor plugs. On a unit with
two motors, the double-shafted motor will always be to
the left side, and will be designated as Motor 2 by the
controller.
Replacement Checklist
NOTICE
Equipment Damage!
Failure to follow these instructions could result in
equipment damage.
The motor harness attached to the single plug to
which the motor mates contains the 115V motor
voltage jumper. The motor harness should always be
present for 115V units and should not be modified or
substituted.
☐ Ensure that motor harness is correct (harness will have
jumper installed for 115V units only).
☐ Ensure that configuration on the VelociTach motor
control board matches the affixed label.
BCX-SVX002A-EN
Diagnostics and Troubleshooting
☐ Maintain correct plug/motor association. The plugs will
have the motor number and shaft configuration printed
on an affixed label.
☐ Ensure that configuration of switches on CSTI adapter
board matches depiction of switches on the unit
schematic.
☐ Ensure that all wires are plugged in securely.
☐ Ensure that edge protection on sharp edges,
grommets, and wire management devices are
maintained when replacing components.
☐ Ensure that blunt-tip screws are used when in the
proximity of wire harnesses.

Circuit Module Replacement

1. Circuit modules are equipped with nylon standoffs
which can either be removed by squeezing the barbs at
the rear of the control panel, or squeezing the latch
above the circuit module. If the latter method is chosen,
the standoffs will be retained on the metal panel. The
new standoffs (affixed to the replacement modules) can
be removed if necessary, so the new module circuit
board can be attached to the retained standoffs.
Figure 105. Remove PCB
2. If replacing the VelociTach motor control board, special
care should be taken to avoid electro-static discharge
damage. Please use an ESD protection wrist-strap and
frequently touch a grounded surface (with unit power
off) to discharge any static buildup.
3. Replace connectors carefully onto the appropriate
board. For units with a green wire attached to the CSTI
or standard adapter boards, please ensure that the
green wire is attached to the engine board white
connector as shown in the following figure.
Depress latch to
remove PCB, leaving
standoff attached to
metal panel
141