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MS8C / MS8H (208-230V)
Table 19. 18-24 kBtu System Status and Error Codes
—
Indoor Character Display and Outdoor LEDs
Indoor
Unit
Display
Outdoor Unit LED Status
Error Description
System Status
Troubleshooting for Possible
Causes
This unit has three display
status indicators
o
OFF
n
ON
®
BLINKS
D5
D6
D16
D30
NONE
n
n
n
n
System is operating within normal parameters
C5
Indoor control jumper is
missing (labeled JUMP)
All system functions are
terminated.
Indoor control jumper is missing or
is not installed correctly. (Indoor
control jumper location is labeled
JUMP
.)
EE
o
o
o
n
EEPROM failure
Replace outdoor control.
E1
o
®
®
®
System high pressure
Check for low refrigerant charge,
blocked coil or excessively high
outdoor ambient temperature.
E2
n
o
n
o
Indoor coil freeze
protection
The indoor coil sensor (RT2) moni
tors the coil temperature continu
ously. When the coil
temperature drops below 30.2ºF
(-1ºC), the compressor and out
door fan (30 seconds later) are
switched off until the coil tempera
ture rises above 42.8ºF (6ºC) and
the compressor has
been off for a minimum of three
minutes. All system functions are
terminated except indoor fan.
Check for reduced indoor airflow
(restricted filter), restricted refriger
ant flow, low ambient temperature
(outdoor) and low indoor system
load. Correct, if necessary.
E4
n
o
n
®
Discharge line temperature
protection
The compressor discharge line
sensor (RT5) monitors the temper
ature continuously and communi
cates with the outdoor unit micro
processor. Depending on the tem
perature measured, the compres
sor speed will be increased to
meet the load or will continue to
run at the existing speed. If the
discharge line temperature be
comes excessively high, the com
pressor will be de-energized.
When the compressor discharge
temperature drops below 194ºF
(90ºC), the unit will resume normal
operation. See figure 72.
Check for low system refrigerant
charge. Check capillary tubes for
blockage. Correct, if necessary.
E5
o
n
®
o
Compressor over-current
protection
All system functions are termi
nated except indoor fan.
Over-current protection error can
result due to any of the following:
S
Ambient temperature is too high.
Check for locked rotor on the
compressor.
S
Check for blocked refrigeration
circuit (capillary tubes for exam
ple). Correct, if necessary.
S
Check for blocked or restricted
outdoor air. Correct, if necessary.
E6
o
o
o
®
Communication failure between
indoor unit and outdoor unit
All system functions except indoor
fan are terminated after a 3-minute
delay.
If error is displayed on outdoor
unit, check communications cable /
wire at indoor and outdoor controls
to verify proper connection. See
unit information manual for further
information.
E8
n
o
n
n
Compressor high temperature
protection
All system functions are termi
nated except indoor fan.
See unit information manual for
further information.
