Mitsubishi Electric CITY MULTI PUHY-400YMF-B, Service Handbook

Page: 100 / 204

–97–
Item
At compressor is started
After thermostat reset or 3
minutes after startup
Compressor stopped during
cooling or heating mode
After operation has been stopped
During defrosting ((*1) in Fig
below)
When low pressure (63LS) has
dropped
When the high pressure (Pd) is
risen up
When the discharge temperature
(Td) is risen up.
When the high pressure (Pd) is
fallen up.
* Example of SV1 operation
Compressor
Bypass
solenoid
valve (SV1)
(4-minute)
(3-minute) (4-minute) (3-minute)
Start Thermo.
OFF Thermo.
ON Defrost
(*1)
Stop
<Constant Capacity Unit>
SV1
ON for 4 minutes
ON for 4 minutes
ON for 3 minutes
ON for 3 minutes
ON during normal operation
—
SV4
—
—
—
—
—
3) Capacity control solenoid valve (SV22, SV32) *Model 500 only.
• Operation of solenoid valve
• SV22 and SV32 stand for SV2 and SV3 of the No. 2
compressor.
Solenoid valve
SV22
SV32
COMP
SV22 SV32
Coil Valve Coil Valve
OFF Open OFF Closed
ON Closed ON Open
Status
Full-load
(Operating at 100 %
capacity)
Un-load
(Capacity control
operation)
ON OFF
Low pressure
(63LS) < 1.0 kg/cm
2
G
(0.098 MPa)
Pd 26.5 kg/cm 2 G
(2.55 MPa)
When the discharge
temperature > 130
°
C
and high pressure
(Pd) > 20 kg/cm
2
G
(1.96 MPa) or low
pressure (63LS) <
2.5 kg/cm
2 G
(0.245 MPa).
Low pressure
(63LS)
1.5 kg/cm
2
G
(0.147 MPa)
Pd 23 kg/cm
2
G
(2.25 MPa) and
after 30 seconds
When the dis-
charge tempera-
ture 115
°
C
—
—
—
In heating mode, at starting
and low volume of indoor
unit, if high pressure (Pd) <
12 kg/cm
2 G (1.18 MPa) and
low pressure saturation
temperature (ET) < – 20
°
C
—
—
—
When the high
pressure (Pd)
13 kg/cm
2
G
(1.27 MPa) and
after 30 minutes of
operation.
(4-minute)
ON OFF