8.4.1.6 Inverter module (IPM) malfunction diagnosis and solution.
Malfunction decision
conditions
When the voltage signal that IPM send to compressor drive
chip is abnormal, the display LED will show “P6” and AC will
turn off.
Supposed causes
● Wiring mistake
● IPM malfunction
● Outdoor fan ass’y faulty
● Compressor malfunction
● Outdoor PCB faulty
Trouble shooting:
IPMmoduleprotection
Checkwhetherthevoltagerange
ofP‐NonIPMmoduleisnormal?
DC277‐356Vfor18‐27KBtu/h;
DC277‐410Vfor36K‐48KBtu/h
Yes
Yes
No
Yes
Checkwhethertheinput
powersupplyiscorrect?
208‐230V,1N,60Hz
No No
Regulateittocorrect,then
checkwhetherthesystem
canworknormally?
Checkwhetherthe
powersupplylineis
connectedcorrectlyand
tightly
Yes
Connectitcorrectly
andtightly,checkok
ornot?
No
Checkwhethertheconnecting
linebetweenmainboardand
theIPMmoduleisconnected
tightly
Yes
Connectittightly,
checkokornot?
No
No
No
Connectitwell,check
okornot?
Checkwhethertheconnecting
lineofthecompressoris
connectedcorrectlyortightly
ReplacetheIPMmodule,
checkwhetherthesystemcan
worknormally?
No
No
Replacethemainboard;check
whetherthesystemcanwork
normally?
No
Replacethecompressor,check
whetherthesystemcanwork
normally?
Checkwhetherthelines
inE‐partboxare
connectedtightly
Yes
Connectittightly,
checkokornot?
No
No
Yes
No
Replacethebridgerectifiers
Checkwhetherthebridgerectifiersare
normal?Usethemultimetertomeasure
theresistancebetweeneachtwo
terminals,checkwhetherthereisthe
conditionthatvalueofresistanceis0
Check whether the connecting line of
every reactor is normal? If the line is
broken,theresistanceofthetwoportsis
∞;Check whether the PFC module
broken.
Replacetheconnectinglineor
reactororreplacethePFCmodule
Yes
No
No
Yes
Troubleissolved
Checkiftheoutdoorfan
runsproperlyortheoutdoor
unitventilationisgood.
No
ForACfanmodels, pleaserefer
to9.4 TroubleCriterionOfMain
Parts,checkwhetherthe
resistanceofthefanmotoris
normal.Ifnot,replacethefan
motor.
ForDCfanmodels,referto
thesolutionoffanspeedhas
beenoutofcontrolmalfunction
.Findoutthecauseandhaveit
solved.
Yes
Yes
Yes