Midea MSC-21CRN1, Service Manual

Page: 38 / 43

Service manual
34
13.3 Detailed malfunction analyse
Cur r ent protectio n
(LED indi cates)
Check t he indoor
air filt er.
Does outdo o r heat -
exchanger fr osted?
No
It is n orma l under
tha t ambient temp .
Che ck t he
dra inage
sys tem of
out door unit.
Yes
Does ind oor heat -
exchan g er frosted?
Yes Check sp eed
of in door
motor.
Yes
No
Doe s the outdoo r
temp over 48 C?
o
Check the out door
condenser.
D oes it occur in
C ool mode?
Che ck speed
of o utdoo r
mo tor.
Yes
Check t he over-
curre n t prot ect or of
comp ressor.
No
Re place the
ma in PCB board .
Re place the
co mpressor.
Recycle the
refrigerant
and recharge .
No
Doe s the ind oor
temp low than 1 0 C?
o
Yes
No
Check t he solenoid
coil o f reve rse valve.
C heck t he ove r-
c urre nt prot ect or of
c ompressor.
Replace th e
main PCB board.
Recycle the ref rig e-
rant and rech arge.
R eplace the re verse
v alve.
Che ck t he positio n
and wiring of tem p
sen sor (all of the m).
If wro ng, t he unit w ill
result in current
prote ction, not tem p.
C heck the soft
st arter mou ld.
Check t h e soft
starter m ou ld.
Indoor /Outdoor Units C ommunic ation Pr otection
Is the L&N c onnections betwe en
indoor and outdoor units corr ec t?
Re conne ct cor re ctly.
Is the c omm unic ation conne ction good?
Re conne ct cor re ctly.
Re place the outdor PC B, the n run th e m ac hine.
Is the com mu nica ti on pro tec tion re lie ved?
I t m e a n s t h a t t h e m a l f u n c t i o n i s
fr om indoor unit. Re pla ce the indoor PC B.
Yes
No
No
Yes
Yes