Service manual


GB
4. Time sequence of defrost process (figure 6).
Control of oil return circle
1. Oil return circle period
When air conditioner has run for 10 minutes or accumulate time Tmsro is end, it execute
oil return circle once.
2. When compressor is running to oil return circle, the indoor unit �hich have
communication is return oil, expand valve is open fully and compressor’s frequency
increase more than 3/5 of max frequency for 90 seconds, the expand valve of indoor unit
�hich no communication is close.
Operation mode control of outdoor unit(dehumidify cooling or heating)
The indoor unit can require cooling mode and dehumidify mode together, but it can’t require
cooling mode or dehumidify �ith heating mode together, the outdoor unit operate state is
decided by the indoor unit �hich is applied first.
Protect function
1. Delay protection of compressor
The compressor can’t run after it stop �ithin 3 minutes.
2. Fault protection of module
The air conditioner stop running immediately and display error code if the module is fault.
3. Protection of communicate fault
The control of outdoor unit can connect �ith all indoor units, �hen it po�er on, it
sent data to each indoor unit continuously, if it receive a correct data from correspond
indoor unit, then the indoor unit is exist. �hen the control of outdoor unit didn’t receive
communication data from indoor unit �hich is exist �ithin 30 seconds, it �ill display
communication fault. If all communication channels are failure, air conditioner �ill
shutdo�n and display fault code.