Midea ATOM B Series - 4 Normal Operation Control

AtomBSeriesVRF50/60Hz
  17
Part3‐Control
2 StopOperation
Thestopoperationoccursforoneofthetwofollowingreasons:
1. Abnormalshutdown:inordertoprotectthecompressors,ifanabnormalstateoccursthesystemmakesa'stopwith
thermooff'operationandanerrorcodeisdisplayedontheoutdoorunitdigitaldisplays.
2. Thesystemstopswhenthesettemperaturehasbeenreached.

3 StartupControl
3.1 CompressorStartupDelayControl
WhentheODUispoweredonagainandthecompressordelaysabout7minutestostart.Afterthecompressorstopsrunning,
ittakesabout4minutestorestart,inordertopreventfrequentcompressoron/offandtoequalizethepressurewithinthe
refrigerantsystem.
3.2 StartupControlforCoolingOperation
Table3‐3.1:Componentcontrolduringstartupincoolingmode
Component
Wiring
diagramlabel
28‐60model Controlfunctionsandstates
Invertercompressor  COMP ●
Controlled according to load requirement, operating
frequencyincreasedby1step/sec
DCfanmotor  FAN
●
Theoutdoorunitfanstartby14gearsfor20secondsbefore
compressor start, and then maintain the fan speed for
another 20 seconds when compressor start, finally the fan
speed controlled according to heat exchanger temperature
(T3), outdoor ambient temperature (T4) ,discharge
temperature(T5)andcompressorfrequency.
Electronicexpansionvalve  EEV
●
Maintain304(step)for3minutesbeforecompressorstartup，
thencontrolledaccordingtodischargetemperature
Four-wayvalve ST1
●
Off

3.3 StartupControlforHeatingOperation
Table3‐3.2:Componentcontrolduringstartupinheatingmode
Component
Wiring
diagramlabel
28‐60model Controlfunctionsandstates
Invertercompressor  COMP ●
Controlled according to load requirement, operating
frequencyincreasedby1step/sec 
DCfanmotor  FAN
●
Theoutdoorunitfanstartby14gearsfor20secondsbefore
compressor startup, and then maintain the fan speed for
another 20 seconds when compressor start, finally the fan
speed controlled according to heat exchanger temperature
(T3),outdoorambienttemperature(T4)andcompressor
frequency.
Electronicexpansionvalve  EEV
●
Maintain 304 step(model 28/42) or 480 step(model
36/48/56/60)for3minutesbeforecompressorstartup,then
controlledaccordingtodischargetemperature
Four-wayvalve ST1
●
On
 