Carrier 42QHF009DS Service Manual page 55

When auto, After an hour running under economic mode ,if it is under cooling mode the set temp will rise 1℃,
if it is under heating mode the set temp will decrease 1℃, if it is under fan-only mode the set temp will be
changeless; the condition will be the same after the air conditioner running under economic mode after 2
hours, and during the next time the set temp do not change.
11.7.8.3 Operation time in sleep mode is 7 hours. After 7 hours the AC quits this mode and the AC will turn
off.
11.7.8.4 Timer off and remote controller off signals have the priority compared with sleep function.
11.7.9 Auto-Restart function
The indoor unit is equipped with auto-restart function, which is carried out through an auto-restart module. In
case of a sudden power failure, the module memorizes the setting conditions before the power failure. The
unit will resume the previous operation setting (not including swing function) automatically after 3 minutes
when power returns.
If the memorization condition is forced cooling mode, the unit will run in cooling mode for 30 minutes and
turn to auto mode as 24℃ setting temp.
If AC is off before power off and AC is required to start up now, the compressor will have 1 minute delay
when power on. Other conditions, the compressor will have 3 minutes delay when restarts.
11.7.10 Drain pump control (For Duct & Cassette)
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) and forced cooling mode or dry mode, the
pump will start running immediately and continuously, till stop cooling or dry or no capacity demand.
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 falls down below the control point (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,
11.7.11 Mode conflict
The indoor units can't work cooling mode and heating at same time.
Heating mode has a priority.
(1) Definition
Cooling mode
Cooling mode
Heating Mode
Fan
Off
No: No mode conflict;
Heating Mode
No Yes
Yes No
No Yes
No No
Fan
No
Yes
No
No
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Off
No
No
No
No