Haier AW07EH2VHA Service Manual page 13

Components ......................................................................................................................................................................... B-2
Service Monitor Board (SMB) .............................................................................................................................................. B-2
Module Circuit Board (MCB) ................................................................................................................................................ B-2
Electronic Control Unit Circuit Board (ECU) ....................................................................................................................... B-3
Power Circuit Board (PCB) ................................................................................................................................................... B-4
Outdoor Fan Motor .............................................................................................................................................................. B-5
Low Pressure Switch............................................................................................................................................................ B-5
4 Way Valve .......................................................................................................................................................................... B-5
High Pressure Switch ........................................................................................................................................................... B-5
Compressor ......................................................................................................................................................................... B-6
EEV Valves............................................................................................................................................................................ B-6
Crankcase Heater ................................................................................................................................................................ B-6
Temperature Sensors .......................................................................................................................................................... B-7
Operations............................................................................................................................................................................ B-8
Cooling Mode Sequence of Operation ............................................................................................................................... B-8
Heating Mode Sequence of Operation ............................................................................................................................. B-10
Outdoor Frequency Control ............................................................................................................................................. B-12
Electronic Expansion Valve (EEV) Control ........................................................................................................................ B-12
Valve Adjustments Due To Hot Gas Discharge Temperature Limits .............................................................................. B-12
4-Way Valve Control During Heating Mode ..................................................................................................................... B-12
Crankcase Heater Control ................................................................................................................................................. B-12
On Demand Defrost Logic ................................................................................................................................................ B-12
Initiating Forced Defrost Operation ................................................................................................................................. B-13
Defrosting Time Flowchart ............................................................................................................................................... B-13
Frequency Control and Compressor Discharge Line Temperature ................................................................................ B-13
Frequency Control when there is CT Over-current Protection ...................................................................................... B-13
High Pressure Protection .................................................................................................................................................. B-13
Low Pressure Protection ................................................................................................................................................... B-13
Forced Defrost Operation ................................................................................................................................................. B-14
Preventing Compressor Overcurrent .............................................................................................................................. B-14
The Protection Function of AC Current: .......................................................................................................................... B-14
Antifreezing Protection of the Indoor Heat Exchanger ................................................................................................... B-14
Testing ................................................................................................................................................................................ B-15
Outdoor Fan Motor ............................................................................................................................................................ B-15
Temperature Sensor .......................................................................................................................................................... B-15
4-Way Valve ....................................................................................................................................................................... B-16
Electronic Expansion Valve (EEV) ..................................................................................................................................... B-16
Variable Speed Compressor ............................................................................................................................................. B-17
Wiring Error Check ............................................................................................................................................................. B-17
Wiring Diagrams ................................................................................................................................................................. B-18
DIP Switch Settings ............................................................................................................................................................ B-21
Error Codes ......................................................................................................................................................................... B-23
OUTDOOR TECHNICAL OVERVIEW
Table of Contents
OUTDOOR TECHNICAL OVERVIEW
2U18MS2VHB
3U24MS2VHB
4U36MS2VHB
B-1