Eco Air CTBU-09HWFN1-M(C), Service Manual, Page: 109 / 219

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15.4.11 Drain pump control
Adopt the water-level switch to control the
action of drain pump.
Main action under different condition :( every 5
seconds the system will check the water level
one time)
1. When the A/C operates with cooling
(including auto cooling), dehumidifying, and
forced cooling mode, the pump will start
running immediately and continuously, till stop
cooling.
2. Once the water level increase and up to the
control point, LED will alarm and the drain
pump open and continue checking the water
level. If the water level fall down and LED
disalarmed (drain pump delay close 1 minute)
and operate with the last mode. Otherwise the
entire system stop operating (including the
pump) and LED remain alarming after 3
minutes,