Carrier 69NT40-511-310 - Unit Runs but Has Insufficient Cooling; Unit will Not Heat or Has Insufficient Heating; Unit will Not Terminate Heating; Unit will Not Defrost Properly

5-2T -296
CONDITION POSSIBLE CAUSE
REMEDY/
REFERENCE
SECTION
5.3 UNIT RUNS BUT HAS INSUFFICIENT COOLING
Compressor Compressor valves defective 6.8
Abnormal pressures 5.7
Controller malfunction 5.9
R
e
f
r
i
g
e
r
a
t
i
o
n
S
y
s
t
e
m
Evaporator fan or motor defective 6.16
R
e
f
r
i
gerat
i
on
S
ystem
Suction modulation valve malfunction 6.18
Condenser Pressure Transducer defective Check
Shortage of refrigerant 6.7.1
5.4 UNIT WILL NOT HEAT OR HAS INSUFFICIENT HEATING
Start-Stop switch OFF or defective Check
No operation of any kind
Circuit breaker OFF or defective Check
N
o
o
p
e
r
a
t
i
o
n
o
f
a
n
y
k
i
n
d
External power source OFF Turn ON
Circuit breaker or fuse defective Replace
Control T ransformer defective Replace
No control power
Evaporator fan internal motor protector open 6.16
N
o
c
o
n
t
r
o
l
p
o
w
e
r
Heat relay defective Check
Heater termination switch open 6.15
Heater(s) defective 6.15
Heater contactor or coil defective Replace
Evaporator fan motor(s) defective or rotating backwards 6.15/6.16
Unit will not heat or has insu
f
f
i-
Evaporator fan motor contactor defective Replace
U
n
i
t
w
i
l
l
n
o
t
h
e
a
t
o
r
h
a
s
i
n
s
u
f
f
i
-
cient heat
Controller malfunction 5.9
Defective wiring Replace
Loose terminal connections T ighten
Low line voltage 2.3
5.5 UNIT WILL NOT TERMINATE HEATING
Controller improperly set Reset
U
n
i
t
f
a
i
l
s
t
o
s
t
o
p
h
e
a
t
i
n
g
Controller malfunction 5.9
U
n
i
t
f
a
i
l
s
t
o
s
t
o
p
h
e
a
t
i
n
g
Heater termination thermostat remains closed along with
the heat relay
6.15
5.6 UNIT WILL NOT DEFROST PROPERLY
Defrost timer malfunction (Cd27) Table 3-5
Loose terminal connections T ighten/
Will not initiate defrost
i
l
l
Defective wiring Replace
W
i
l
l
n
o
t
i
n
i
t
i
a
t
e
d
e
f
r
o
s
t
automatically
Defrost temperature sensor defective or heat termination
thermostat open
Replace
Heater contactor or coil defective Replace
Will not initiate de
f
rost
Manual defrost switch defective Replace
W
i
l
l
n
o
t
i
n
i
t
i
a
t
e
d
e
f
r
o
s
t
manually
Defrost temperature sensor open 4.10.4
Initiates but relay (DR) drops
out
Low line voltage 2.3
I
n
i
t
i
a
t
e
s
b
u
t
d
o
e
s
n
o
t
d
e
f
r
o
s
t
Heater contactor or coil defective Replace
I
n
i
t
i
ates
b
ut
d
oes not
d
e
f
rost
Heater(s) burned out 6.15
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