Mitsubishi Electric CITY MULTI PUHY-400YMF-B, Service Handbook, Page: 99 / 204

–96–
Item
At compressor is started
Compressor stopped during cool-
ing or heating mode
After operation has been stopped
During defrosting ((*1) in Fig below)
During oil recovery operation
When low pressure saturation
temperature (TH2) has dropped
during lower limit frequency opera-
tion(15 minutes after start)
When the high pressure (Pd) is
risen up during lower limit fre-
quency operation (3 minutes after
starting)
When the discharge temperature
(Td) is risen up
TH2 – 15
°
C
Pd 23 kg/cm 2 G
(2.26 MPa) and
after 30 seconds
Pd 20 kg/cm
2
G
(1.96 MPa)
Td 115
°
C
* Example of operation of SV1
Compressor
Bypass
solenoid
valve (SV1)
(4-minute)
(2-minute) (4-minute) (3-minute)
Start
Thermo.
OFF Thermo.
ON
Defrost
Stop
2) Bypass solenoid valves (SV1, SV4) [Both SV1 and SV4 are on (open)]
<Variable capacity unit>
SV1
ON OFF
ON for 4 minutes
ON
ON for 3 minutes
ON
ON during oil recovery operation after con-
tinuous low-frequency compressor opera-
tion.
—
—
—
TH2 < – 30
°
C
Pd 23 kg/cm 2 G
(2.26 MPa)
ON when the high
pressure (Pd) ex-
ceeds the control
pressure limit.
• Td > 130
°
C
and
• Pd > 20 kg/cm 2 G
(1.96 MPa)
or
TH2 < – 10
°
C
SV4
ON OFF
—
—
—
Normally ON
—
Pd 27.5 kg/cm
2
G
(2.70 MPa)
Pd 24 kg/cm 2 G
(2.35 MPa) and
after 30 seconds.