- 92 -
No.1 Compressor
Stopped
Stopped
OFF
In operation
Stopped
ON
In operation
In operation
OFF
No.2 Compressor
SV3
When low pressure (LPS) drops in
heating-only or heating-main operation
(5 or more minutes after compressor startup)
When low pressure (LPS)
drops below 0.25 MPa.
When low pressure (LPS)
rises above 0.39 MPa.
Item
ON
OFF
SV2
ON for 4 minutes
ON for 2 minutes
Always ON. (Exception : OFF when HPS-LPS 0.2MPa)
ON for 3 minutes. (Exception : OFF when HPS 0.2MPa)
Always ON
Always OFF during cooling operation and always ON
during heating operation when running an oil-recovery operation after running a
continuous operation at low frequency.
When low pressure (LPS) drops
below 0.23 MPa.
When low pressure (LPS) exceeds
0.38 MPa.
When Pd exceeds 3.77 MPa
When Pd is or below 3.43MPa and
30 seconds has passed
SV1
Operation Timing
ON (Open)
OFF (Close)
At No. 1 compressor start up
or at No. 2 compressor start up
(P450-P650 types only)
After the restoration of thermo
or 3 minutes after restart
During cooling or heating operation
with the compressor stopped
After the operation has stopped
During defrost operation
(See figure
✻
1 below)
During oil-recovery operation
During an operation with the
compressor running at 30Hz
When low pressure (LPS) drops
(After 3 minutes have past since
start up)
When high pressure (Pd) rises
[ Example of an SV1 operation ]
Start
up
Thermo.
Thermo.
Defros-
ting
Time
Stop
OFF
ON
Compressor
Bypass solenoid
valve (SV1)
(4-minute)
(2-minute)
(8-minute)
(3-minute
)
3. Bypass control
Bypass solenoid valves (P200-P400: SV1, SV2, P450-P650: SV1, SV2, SV3), which bypass the high- and low-
pressure sides, operate in the following manner.
(1) Bypass solenoid valve (SV1) (ON = Open)
(3) Bypass Valve (SV3, P450-P650 types only) (ON = Open)
• The opening SV3 is controlled by the configuration of No.1 and No.2 compressor operations.
(2) Bypass solenoid valve (SV2) (Open when ON)
