GE APN08 Series Technical Service Manual page 19

Circulation Pump Float Switches
There are 2 fl oat-operated switches in the
condensate water circulation system. The low-
level switch, CN10, controls the pump. The high-
level switch, CN9, acts as a safety to prevent
fl ooding.
Low-Water-Level Switch
High-Water-Level
Switch
Float Switch Operation
When the drain sump is empty, both switches
are open. When the water level rises, the low-
level switch closes and starts the pump. When
the water level drops, the switch opens and the
pump stops. At higher water levels, the low-level
switch stays closed and the circulation pump runs
continuously. If the low-level switch stays closed
for longer than 15 minutes, the condenser fan,
normally operating at high speed during COOL,
will change to low speed.
If the water level continues to rise, the high-
level switch closes and:
• After 1 minute, the WATER FULL indicator
light fl ashes.
• The compressor and evaporator fan shut
down.
• The condenser fan operates at high speed.
• The circulation pump continues to run.
If the high level switch stays closed for 40
minutes, the unit beeps twice and:
• The condenser fan and circulation pump shut
off.
• The WATER FULL indicator light stays on,
and all other indicator lights on the control
board turn off.
• The unit displays the room temperature.
Note: The low and high level switches must be
open and the unit must be manually drained and
restarted to resume operation.
WARNING: If condenser air fl ow is restricted,
condensate in the sump may become hot.
If the sump overfl ows and the pump is not
running:
• Check for 120 VAC between CN13 and CN2
on the power supply board. If voltage is
present, replace the pump.
• If 120 VAC is not present between CN13 and
CN2, check for 5 VDC at CN10. If 5 VDC is
not present, replace the board.
• If 5 VDC is present, check continuity of the
low-level switch at CN10 on the power supply
board.
• If the switch is open, check for an inoperative
fl oat or defective switch.
• If the unit has not shut down after 40 to 45
minutes during high condensate levels, check
for continuity of the high-level switch at CN9.
If the switch is open, check for an inoperative
fl oat or defective switch. If the unit still fails to
shut down, replace the board.
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