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6. Hot Gas Defrosting Control
6-2. Defrosting operation conditions
(1) Defrosting operation is performed after at least 35 minutes of total operation during heating operation.
* Even in outdoor units where a total operation time of 35 minutes has not elapsed, defrosting operation will be
performed if other outdoor units satisfying the conditions above start defrosting operation.
(2) Once defrosting operation is finished, defrosting operation does not start again for 10 minutes (even when opera-
tion is stopped while defrosting is in progress).
(3) If the CHECK. PIN (CP) on the outdoor unit control P.C.B is short-circuited during operation, the defrosting opera-
tion conditions are met, and defrosting operation is forced to start. However, defrosting operation is not performed
for the 10 minutes described in (2) above. Also, be sure to remove the CHECK. PIN (CP) if this operation has been
performed.
6-3. Defrosting end conditions
(1) Minimum temperature of the sensor mounted to the outdoor unit heat exchanger must be ] 6°C
(2) Maximum of 12 minutes
6-4. Defrosting control description
Table 14
Control units
Hot gas valve
Constant-speed
compressor
LPV
HPV
Save valve
4-way valve
Outdoor fan
Refrigerant
adjustment valve
Outdoor electronic
expansion valve
NOTE
The target maximum capacity of all operating outdoor units is transmitted during
defrosting control.
7. Self-Separator Oil Recovery Control
¶ Control is performed for oil recovery from the oil separator of the unit itself. The recovery valve and balance valve are
turned on at the same time.
8. Inter-Outdoor Unit Oil Recovery Control
6
¶ Control is performed on oil exchanges (supplying and receiving) with other outdoor units by passing through the
balance pipes. However, this control is only performed when multiple outdoor units are operating. This control is
performed when the oil of compressor does not return to the original level after self-separator oil recovery is per-
formed.
¶ Oil-supplying unit : The balance valve and bypass valve turn on and off alternately.
¶ Oil-receiving unit : The recovery valve is turned on.
* The balance valve is set to high and low pressure by the turning on and off of the balance valve and bypass valve.
Control unit operation during defrosting operation
During hot gas defrosting operation After defrosting operation
(maximum of 12 minutes)
ON
Maximum capacity (protection control priority)
ON
ON
Stop
ON
Control at 80 to 250 pulses
OFF
Normal control
ON
Normal control
Normal control
Normal control
VI - 8
Processes and Functions
TD831077
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