Carrier 38MGQ Series - High Pressure Protection Error Diagnosis (P1)

55
P1(High pressure protection) error diagnosis and
solution.
Error Code P1
Malfunction decision conditions If the sampling voltage is not 5V, the LED displays the failure.
Supposed causes
S Wiring mistake
S Over load protector faulty
S System block
S Outdoor PCB faulty
Troubleshooting
Wh
et
h
er t
h
e w
i
r
i
ng
b
etween t
h
e
hi
g
h
pressure
s
w
i
tc
h
an
d
ma
i
n contro
l
b
oar
d
i
s connecte
d
we
ll
or
c
orrect
ly
Whether the wiring
between the high pressure
switch and main control
board is connected well or
correctly
M
et
h
o
d
:
Di
sconnect t
h
e p
l
u
g
.
Measure the resistance o
f
th
e
hi
g
h
pressure protector
,
if
t
h
e protector
i
s norma
l
t
h
e
v
a
l
ue
i
s o
,
Method: Disconnect the plug.
Measure the resistance of
the
high pressure protector, if
the protector is normal the
value is o,
Yes
Yes
C
onnect it well
Connect it well No
R
ep
l
ace
hi
g
h
pressure protector
Replace high pressure protector No
Wh
et
h
er t
h
e
hi
g
h
p
ressure protector
i
s
b
ro
k
en
Whether the high
pressure protector
is broken
C
heck whether the outdoor
am
bi
ent temperature
i
s
hi
g
h
er t
h
an
Check whether the outdoor
ambient temperature is
higher than 122 °F
No
Stop the unit
Stop the unit Yes
C
heck i
f
the outdoor unit
l
d
Check if the outdoor unit
Yes
M
ak
e t
h
e out
d
oor un
i
t vent
il
ate we
ll
Make the outdoor unit ventilate well
C
heck whether the heat
exc
h
anger
i
s
di
rt
y
Check whether the heat
exchanger is dirty
No
C
lean the heat exchanger
Clean the heat exchanger
Yes
C
heck whether the re
f
rigerant
s
ystem
i
s o
k
Check whether the refrigerant
system is ok
R
ep
l
ace out
d
oor ma
i
n
b
oar
d
Replace outdoor main
board
No
Hig
h
p
ressure protec on
C
heck i
f
the outdoor
f
an runs
proper
ly
Check if the outdoor fan runs
properly
please re
f f
f
an
s
peed has been out o
f
control
mal
f
.
F
ind out t
h
e cause and
h
ave it so
l
ved
.
speed has been out of control
have it solved.
No
Yes
NO