Toshiba MMU-P0121H Service Manual page 35

Item
8. Release valve 1) Contents of control
control
SV2 is opened when the following conditions are satisfied.
(Continued)
• Compressor status changes from OFF to ON.
• During defrost control
• Oil recovery controlling is performed in cooling mode.
• SV2 is opened when TK3 sensor detects 2°C or lower
• No. of outdoor fan waves is 3 waves or less during cooling
(5) SV41, 42 low pressure release control
This control is to prevent low pressure lowering in defrost operation.
This control is individually executed by the master outdoor unit and
each terminal outdoor unit.
This control is executed during defrost operation or activation time of
the heating operation.
1) Contents of control
SV41 and 42 are opener (ON) when PS pressure ≤ 0.05 MPa, and
they are closed (OFF) when PS pressure ≥ 0.1 MPa.
9. Fixed-speed This control is to stop the fixed-speed compressor of each outdoor unit
compressor according to Pd pressure value. This control is individually executed by
high pressure the master outdoor unit and each server outdoor unit.
release
1) Contents of control
control
• The fixed-speed compressor stops when Pd pressure is over P1.
• Sets the fixed-speed compressor reactivation-proof timer for 10
10. Compressor This control is to prevent stagnation of refrigerant in the compressor case
winding by turning on electricity to heat windings while the inverter compressor
heating stops. This control is executed by the master outdoor unit (For inverter
control unit) only.
If electricity is not turned on for a specified time before trial operation
when installation work has finished, a fault of the compressor may be
caused. When the power supply has been interrupted for a long time, and
the operation starts from the status that the power supply has been left
as it was, it is desirable to turn on the power before start of operation as
per the trial operation time.
(1) Control conditions
Compressor stops and TD < 35°C.
(2) Contents of control
This control is executed by temperature detected by TK3 sensor as
shown in the following figure.
NOTE :
Sound of turning-on power may be heard during heat winding operation,
but it is not an error/fault.
Continuous
switch-on power
Operation explanation and applied data, etc.
(From when 4-way valve is turned off.)
temperature, and closed when TK3 sensor detects 5°C or higher
temperature during compressor-ON time.
compressor-ON.
minutes, and this control finishes.
TK3
40˚C
35˚C
25˚C
A zone B zone
Intermittent switch-on power
ON : 10 minutes
OFF : 5 minutes
C zone
B zone
A zone
C zone
No
switch-on power
3-32
Remarks
• No. 2 compressor
stops with
Pd ≥ P1 = 2.80 MPa,
• No. 1 compressor
stops with
Pd ≥ P1 = 2.90 MPa,