Toshiba MCY-MHP0404HS-E Service Manual page 33

Item Description of operation, numerical data, and other information
1. SV2 gas balance control
6. Release
This control function is aimed at achieving gas balance by opening SV2 while
valve control
compressor is turned off so as to reduce its startup load the next time it is
turned on.
1) Control conditions
The compressor has been turned off.
2) Control details
The control point is changed according to P (PD pressure - PS pressure)
registered just before the compressor was turned off.
When P 1.3MPa, SV2 is opened. When this results in P 1.1MPa, SV2 is
closed.
When P 1.3MPa, SV2 is closed.
2. SV2 high pressure release control
This control function is aimed at mitigating pressure rise while a compressor is in
operation at low speeds.
1) Control conditions
Heating operation is in progress (except periods of defrosting control).
A speed of the compressor is in operation at low speeds of up to 77 rps.
2) Control details
When PD pressure becomes 3.4 MPa, SV2 is opened.
When PD pressure becomes 2.8 MPa, SV2 is closed.
3) Termination conditions
Shutdown, thermostat OFF, defrosting operation, or cooling operation.
The speed of the compressor rises to 82 rps or more.
3. SV2 low pressure release control
This control function is aimed at preventing a rapid fall in pressure during transient
operation.
The control is always provided except during periods of stoppage or thermostat OFF.
1) Control details (heating)
When PS pressure becomes 0.1 MPa, SV2 is opened.
When PS pressure becomes 0.2 MPa, SV2 is closed.
2) Control details (cooling)
When PS pressure becomes 0.25 MPa, SV2 is opened.
When PS pressure becomes 0.30 MPa, SV2 is closed.
4. SV4 low pressure release control
This control function is aimed at providing low pressure protection.
1) Control details (heating)
When PS pressure becomes 0.1 MPa, SV4 is opened; when PS pressure
becomes 0.2MPa, SV4 is closed.
2) Control details (cooling)
When PS pressure and PD pressure become 0.14 MPa and 1.8 MPa,
respectively, SV4 is opened; when PS pressure and PD pressure become
0.24 MPa and 2.2 MPa, respectively, SV4 is closed.
5. SV5 high pressure release control
This control function is aimed at mitigating pressure rise.
1) Control details (heating)
When PD pressure and compressor speed become 3.4 MPa and 38 rps,
respectively, SV5 is
compressor speed 42 rps, SV5 is closed.
AMP Air Conditioning
opened; when PD pressure becomes 2.7 MPa, or
28 32
Remarks
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