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Heat Mode; Indoor Fan Control; Cold Air-Proof Operation; Timing - Haier 2U18MS2VHB Service Manual

Ductless multi-split heat pump, outdoor/indoor, wall mount - highwall, 2'x2' compact cassette, 3'x3' large cassette, slim duct, mid-static ducted, medium static ducted, console
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Heat Mode

• Temperature control range: 60-86°F
• Temperature difference: ±2°F
Control feature: the temperature compensation is
automatically added and the system will send the heating
signals to the outdoor system.
If Tr≤Ts, the outdoor compressor is turned on, the indoor fan
will be at the cold air proof mode.
If Tr>Ts+, the outdoor system is turned off, the indoor fan will
be at the heat residue sending mode.
If Tr<Ts+, the outdoor system will be turned on again, the
indoor fan will be in the cold air proof mode.

Indoor Fan Control

Manual Control: You can choose high, medium, low and
automatic speed control. Automatic:
When Tr<Ts, high speed.
When Ts≤Tr≤Ts+4°F, medium speed.
When Tr> Ts+4°F, low speed.
When the airflow speed has no delay from the high to low
switching, the speed should be delayed for 3 minutes (remain
at high speed for 3 minutes.) before the next switch.
• Louver location control: the location for the louver can be
set according to your needs.

Cold Air-Proof Operation

1. The indoor operation within 4 minutes after the start up is
as the following diagram, the air speed can be raised only
after the speed has reached a certain level.
2. 4 minutes after the start up of the indoor fan, the light
airflow and the low airflow will be turned to the set speed
3. In the cold air proof operation, the fan won't stop after the
start up.
4. During the cold air proof operation, the indoor system
will continuously send 'indoor high speed' signals to the
outdoor system.
Functions and Control
• Residue heat sending. The indoor fan will send the residue
heat at a low speed for 12 seconds.
• If other conditions are satisfied, when the compressor stops,
the indoor system will operate at a light speed. The indoor
fan will stop when the coil temperature is below the heat
start temp 4'.
• Defrosting. When the system receives the defrosting signal
from outdoors, the indoor fan will stop and the indoor
temperature display won't change. At this time, any indoor
coil malfunctions will be neglected. When the outdoor
defrosting finishes, the coil malfunction will still be neglected
until the compressor has been started up for 30 seconds.
The indoor temperature display will not change and the
system operates at the cold air proof mode.
• Automatic heating temperature compensation: when
the system enters the heating mode, the temperature
compensation (4) will be added. When the status is switched
off, the compensation will be erased.


You can set 24 hours on/off timing. After setting, the timing
indicator will be displayed. Also, the light will turn off after the
timing is set. The followings are several timing methods:
1. System ON timing: The timing indicator will be displayed
and the indoor system is under the waiting mode. The light
will be turned off when the timing is finished and the rest
of the system will operate under a normal condition. The
timing starts since the last reception of the timing signal.
2. System /OFF timing: When the system is turned on, the
timing indicator will be displayed; the rest of the system
will operate under normal conditions. When the set time
expires, the indicator display will turn off and the system
will turn off. If you have set the dormant functions, the
order of your settings will be operated according to the
timing settings.
3. System ON/OFF timing: The settings will be completed
according to the settings.

Indoor System Mode Conflict

The indoor unit is trying to operate in a mode that is opposite
of the mode the outdoor unit is currently operating in. Change
the operating mode to either heat or cool, or the indoor unit
will shut off.

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