Johnson Controls YVAHP072B31S, Service Manual

Page: 935 / 1796

Service Manual
2-15
OPERATION
NOTE
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If the space is large or the room temperature is excessively low, it takes time to heat the entire room.
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“HOT-START” will be turned OFF after heating the room.
Ɣ 7KHLQGLFDWLRQ “HOT-START” may be displayed during, or right after, the defrosting operation.
“HOT-START” is activated during defrost to ensure comfort by reducing the delivery of cold air in the
heating cycle. This is NOT abnormal.
6. Automatic Control
This air conditioner automatically starts the following operations according to the indoor conditions.
Three-Minute Guard
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The compressor remains off for at least three minutes once it has
stopped. If the system is started within approximately three minutes
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However, the cooling operation or the heating operation remains off
and does not start until after three minutes has elapsed.
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If all indoor units of the system are Thermo-OFF within approximately
three minutes after the compressor has started, the compressor is
operated during three minutes continuously.
However, if all indoor units of the system are stopped by a controller,
compressor has stopped.
Cooling
and
Dry
Frost Prevention
When the indoor unit is operated at a low discharge air temperature,
the cooling operation may be changed to fan operation for a while to
avoid frost formation on the indoor heat exchanger.
Self-Cleaning of
Expansion Valve
The expansion valve self-cleaning when the cooling operation has
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the indoor unit during the self-cleaning. This is not abnormal.
Heating
Hot Start
To prevent cold air discharge in the room, the fan speed is controlled
from the slow position and the low position and then to the set position
according to the discharge air temperature.
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displayed on the LCD of the wired controller.
Defrost Operation
The indoor unit fan operation is stopped to prevent cold air discharge
during the defrost operation. At this time, the indication “HOT-START”
is displayed on the LCD of the wired controller and the indoor unit fan
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Residual
Heat Removal
When the heating operation is stopped, the indoor fan operation may
be kept at the slow position for a maximum of two minutes to lower
temperature of the inside of the indoor unit.
Prevention
of Overload
Operation
When the outdoor temperature is high (approx. 70
o
F (21
o
C) or more)
during the heating operation, the operation is stopped by activation of
the outdoor thermistor.
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