15
1. Cold air prevention control
When the compressor is not operating or is starting, and the temperature of indoor heat exchanger and/or the room tem-
perature is low or when defrosting is being done, the indoor fan will stop or rotate in Very Low speed.
2. High pressure protection
The compressor operational frequency is controlled by the temperature of the indoor heat exchanger to prevent the con-
densing pressure from increasing excessively.
When the temperature of indoor heat exchanger becomes too high, the high pressure protection works.
The indoor fan operates following the cold air prevention control. This mode continues until the temperature of indoor
heat exchanger falls.
3. Defrosting
Defrosting starts when the temperature of outdoor heat exchanger becomes too low.
The compressor stops once, the indoor/outdoor fans stop, the 4-way valve reverses, and the compressor re-starts.
This mode continues until the temperature of outdoor heat exchanger rises or the fixed time passes.
9-5. AUTO CHANGE OVER ∙∙∙ AUTO MODE OPERATION
Once desired temperature is set, unit operation is switched automatically between COOL and HEAT operation.
Mode selection
(1) Initial mode
When unit starts the operation with AUTO operation from OFF:
• If the room temperature is higher than the set temperature, operation starts in COOL mode.
• If the room temperature is equal to or lower than the set temperature, operation starts in HEAT mode.
(2) Mode change
COOL mode changes to HEAT mode when about 15 minutes have passed with the room temperature 1°C below the
set temperature.
HEAT mode changes to COOL mode when about 15 minutes have passed with the room temperature 1°C above the
set temperature.
NOTE 1:
If 2 or more indoor units are operating in multi system, there might be a case that the indoor unit, which is operating in
(AUTO), cannot change over to the other operating mode (COOL ↔ HEAT) and becomes a state of standby.
Refer to
NOTE 2 “FOR MULTI SYSTEM AIR CONDITIONER”
.
NOTE 2
FOR MULTI SYSTEM AIR CONDITIONER
OUTDOOR UNIT: MXZ series
Multi system air conditioner can connect 2 or more indoor units with 1 outdoor unit.
• When you try to operate 2 or more indoor units with 1 outdoor unit simultaneously, one for the cooling and the
others for heating, the operation mode of the indoor unit that operates first is selected. Other indoor units cannot
operate, and operation indicator lamp blinks as shown in the figure below. In this case, please set all the indoor
units to the same operation mode.
• When indoor unit starts the operation during defrosting of outdoor unit, it takes a few minutes (max. 10 minutes)
to blow out warm air.
• In the heating operation, though indoor unit is not operating, it may get warm or the sound of refrigerant flow may
be heard. It is not malfunction. The reason is that the refrigerant continuously flows into it.
OPERATION INDICATOR
Lit
Blinking
Not lit
OBH864
