Cold Draught Prevention Control; Idu Exchanger Heat Removal - Toshiba HFCR407C Service Manual

Item
12. Defrost
control
(reverse
defrost
method)
13. Cold draught
prevention
control
11
14. IDU
exchanger
heat removal
Outline of control
Outdoor units
Operation explanation and applied data, etc.
3) For the slave outdoor units
• The compressors 1 and 2 are kept on. Should they be off they will be
switched on.
• After the signal to finish the defrost operation is received from the master
outdoor units, the 4-way valves become switched on.
• The capacity of the compressors is controlled according to the on/off signals
from the master outdoor units thereon.
(5) SV41, 42 low pressure release control
This prevents the low pressure level relaxing during the defrost control operation. The
master outdoor units and slave outdoor units have their own control over this action
when the defrost/heating operation is in progress.
1) Control details
When PS pressure 0.5 kgf/cm
When PS pressure 1.0 kgf/cm
(1) During the heating operation, the indoor fan is controlled according to the
temperature that is detected by TC2 (indoor heat exchange sensor).
(°C)
A
30
B
26
20
C
16
(1) To prevent the IDU heat exchanger remaining hot after operation has stopped the
indoor fan operates in low fan speed for approximately 30 seconds.
2 G, the control switches SV41 and SV42 on.
2 G, SV41, and 42 are switched off.
A zone: set fan operation from the
remote controller
B zone: low fan speed
C zone: OFF
62
Remarks
• "Preheat defrost"
light displayed