York YCAV0157, Installation Operation & Maintenance

Page: 191 / 310

191
JOHNSON CONTROLS
FORM 201.21-NM1 (1223)
VSD TEMPERATURE CONTROL, OPERATION OF THE COOLANT PUMP,
AND VSD CABINET COOLING FANS
The Coolant pump and VSD Cabinet Cooling Fans will
run to cool the VSD whenever any of the following
conditions are met:
·
VSD Comp IGBT Baseplate Temperature on a 2 or
4 compressor unit is greater than 10°F below the
cutout (Cutout [218°F]-10°F =208°F). When the
VSD internal ambient falls below the restart tem-
perature (Cutout [218°F] - 15°F = 203°F), the fans
and pump will turned off without a time delay.
· VSD Comp IGBT Baseplate Temperature on a 3
compressor unit is greater than 10°F below the
cutout (Cutout [232°F] - 10°F = 222°F). When
the VSD internal ambient falls below the restart
temperature (Cutout - 15°F = 217°F), the fans and
pump will be turned off without a time delay.
· Pre-charge Enable 1 from the Chiller Logic Board
is ON.
· Pre-charge Enable 2 from the Chiller Logic Board
is ON.
· VSD Internal Ambient Temp > 158°F (Cutout)
– 10°F = 148°F. When the Internal Ambient Temp
falls < 158°F (Cutout) - 15°F = 143 °F the VSD
cooling fans and glycol pump will turn off.
· Condenser Fans (as needed) and VSD coolant pump/
fans will run whenever a compressor is running.
Under these conditions, the condenser fans will run
to control discharge pressure and the VSD coolant
pump/fans will run to cool the IGBT baseplate and
internal cabinet. Additional condenser fans will be
brought on, if the IGBT baseplate temperatures or
internal cabinet ambient rises to 5°F below the cut-
out. Condenser fans will turn off, if the compressor
turns off provided VSD cooling is not required. The
glycol pump and cabinet fan may continue to run,
if VSD cooling is required.
· Glycol Pump and Cabinet Cooling Fans will also
run in the Service Mode if the Fan/Pump Run Bit
is Set.
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