Control Of Bc Controller - Mitsubishi Electric CITY MULTI PQRY-P200YMF-B Service Handbook

[3] Control of BC Controller

(1) Control of SVA, SVB and SVC
SVA, SVB and SVC are turned on and off depending on connection mode.
Mode
Connection
SVA
SVB
SVC
(2) Control of SVM
SVM is turned on and off corresponding to operation mode.
Operation mode
SVM
(3) Control of LEV
LEV opening (sj) is controlled corresponding to operation mode as follows:
Operation mode
LEV1
LEV3
Superheat
*1
control
Differential
*2
pressure control
*3
–
* Please confirm that the above parts of BC controllers are being color-corded and shown with the name plate inside
the BC controller unit.
Cooling
ON
OFF
ON
Cooling-only Cooling-main
ON OFF
Cooling-only Heating-only
2000 60
Differential
Superheat
Pressure control
control *1
*2
Control every minute so that superheat amount detected by bypass inlet and oulet
temperatures (TH12, TH15) stay in the specified range.
Control every minute so that detected differential pressure (PS1, PS3) stay in the
specified range.
60 or more pulses are sometimes detected because of rise in liquid side pressure (PS1).
Heating Stop
OFF OFF
ON OFF
OFF OFF
Heating-only Heating-main
OFF
Cooling-main
• Liquid level
control *3
• Differential
pressure control
pressure control
*2
–55–
Defrost
OFF
OFF
OFF
Stop
OFF OFF
(Number of pulse)
Heating-main Stop
60 1000
Differential
60
*2