Controlling Bc Controller - Mitsubishi Electric PQHY-P72ZLMU-A Service Handbook

[ VII Control ]

[3] Controlling BC Controller

1. Control of SV A, SV
SV A, SV B, and SV
SV A
Port SV B
SV C
2. Control of SVM1, SVM1b
SVM turns on or off depending on the operation mode.
Operation
Cooling only
mode
SVM1,1b ON
*1. Pressure differential control: The detected differential pressure (PS1 and PS3) 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
LEV1
G,GA,
HA
LEV3
type
GB,HB
LEV3
type
*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 PS3) is controlle every minute so as to be with-
in 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,HA:TH12,TH15, GB, HB: TH12, TH15) is controlled every minute so as to be within a certain range.
4. Control of SVM2, SVM2b
Operation
Cooling only
mode
SVM2,2b OFF
*1. Pressure differential control: The detected differential pressure (PS1 and PS3) is controlled every minute so as to be within
a certain range.
HWE15150
B, and SV C
C turn on or off depending on the operation mode of the branch.
Cooling Heating
ON OFF
OFF ON
ON OFF
Cooling main Heating only
Pressure dif-
ferential con- OFF
*1
trol
Cooling
Cooling only
main
2000
Liquid level
*1
control dif-
Superheat
ferential
*4
*2
control
control
Superheat Superheat
*4 *4
control control
Cooling main
Pressure differ-
OFF
ential control
Mode
Stopped Defrost
OFF OFF
OFF OFF
OFF OFF
Heating main Defrost
OFF ON
Heating only Heating main
*3
110 110
Pressure dif- Pressure dif-
ferential con- ferential con-
*2 *2
trol trol
60 60
Heating only Heating main
Pressure differ-
*1
ential control
- 162 -
Stopped
OFF
Defrost Stopped
2000 1200
G:1000
60
GA,HA:2000
60 60
Defrost Stopped
OFF OFF
*1
GB