Operation Control Of Following Outdoor Unit - Toshiba RAS-M18SAH-E Service Manual

8-13. Operation Control of Following
Outdoor Unit
RAS-M18SAH-E
RAS-3M31SAH-E-1 (Lower Unit)
RAS-4M36SAH-E (Upper and Lower Unit)
8-13-1. In Case of Operation in a Single
Room
The outdoor unit operates by instruction from the in-
door unit.
8-13-2. In Case of Concurrent Operation in
Two Rooms
Heat exchanger of outdoor unit is common use for two
indoor units.
• Unit (A) and (B) cannot operate on different mode
(as (A) unit for Cool, (B) unit for Heat) at the same
time.
• If Cool operation and Heat operation are concur-
rently performed, the priority is given to Heat op-
eration, and Cool operation is exchanged to Fan
operation.
(1) Control in normal operation
The outdoor fan is turned on when ON signal is
output from either one of the indoor units in two
rooms.
(2) Control of heating high-temperature releasing and
current releasing
1) When either one of the indoor units controls
the outdoor fan OFF zone of heating high-tem-
perature release/current release, stop the out-
door fan.
2) When either one of the indoor units controls
the Comp. OFF zone of heating high-tempera-
ture release/current release, follow the outdoor
fan signal from the other indoor unit.
3) If either one of the indoor units controls one of
heating high-temperature release/current re-
lease/defrost while the other unit performs the
defrost reset sequence, the priority is given to
the former unit.
(3) Control in defrost operation
1) When either one of the indoor units performs
the defrost operation, the other unit also con-
trols the defrost operation.
2) Turn off immediately the 4-way valve of the in-
door unit which received the Defrost signal, and
after 12 sec. later, also turn off the outdoor fan
and the 4-way valve in the other room.
3) The concurrent defrost control time is 3 min-
utes and 50 seconds in the unit which did not
receive the Defrost signal, and after then, con-
trol is performed according to the instruction
from the indoor unit. In this case, the outdoor
fan is turned on if the operation signal is output
from one of two indoor units though the other
unit continues the defrost operation.
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