Mitsubishi Electric PURY-P72 Service Handbook page 155

[VII Control]
[3] Controlling BC Controller
1. Control of SV.A, SV. B, and SV .C
SV .A, SV. S, and SV .C turn on or off depending on the operation mode of the branch.
Mode
Cooling Heating Stopped Defrost
SV.A ON OFF OFF OFF
Port SV.S OFF ON OFF OFF
SV.C ON OFF OFF OFF
2. Control of SVM1
SVM turns on or off depending on the operation mode.
Operation
Cooling only Cooling main Heating only Heating main
Defrost Stopped
mode
Pressure dif-
SVM1 ON ferential con- OFF OFF ON
OFF
tro(1
*1. Pressure differential control: The detected differential pressure (PS1 and P3) is controlle every minute so
as to be within a certain range.
3. Control of LEV.
LEV. opening (sj) is controlled as follows depending on the operation mode.
Operation mode Cooling only
Cooling
Heating only
Heating
Defrost
Stopped
main main
LEV1
LEV2
2000
Liquid level
110
110"3
2000 1200
G,GA
(only GA type)
contro(1 dif-
type ferential
Superheat
contro(2
Pressure dif- Pressure dif-
G:1000
LEV3 ferential con- ferential con- 60
contro(4
tro(2 tro(2
GA:2000
GS,HS
LEV3
Superheat Superheat
60
60 60 60
type
contro(4
contro(4
*1. Liquid level control: The liquid level detected by the liquid inlet temperature (TH11 sensor) is controlled so as to be within
a certain range.
*2. Pressure differential control: The detected differential pressure (PS1 and P3) is controlle every minute so as to be within
a certain range.
*3. Can be 110 or more due to pressure rise on the liquid side (PS1).
*4. Superheat control: The amound of superheat that is calculated on the bypass inlet and outlet temperature (G, GA,
H:TH12,TH15, GB, HB: TH12, TH15) is controlled every minute so as to be within a certain range.
4. Control of SVM2
Operation
Cooling only Cooling main Heating only Heating main Defrost Stopped
mode
SVM2 OFF OFF
Pressure differ- Pressure differ-
OFF OFF
ential contro(1
entiaI contro(1
*1. Pressure differential control: The detected differential pressure (PS1 and P3) is controlled every minute so as to be with-
in a certain range.
HWE0803A
- 145- GB