Lennox MS8 SERIES Installation And Service Procedures page 61

Continued — 09 through 12 and 30 kBtu System Status and Error Codes — Indoor Character Display and Outdoor LEDs
Outdoor LED Displays
Indoor
(number of blinks)
Character
Display
Yellow Red
U7 OFF OFF
NONE 1 OFF
NONE OFF 8
NONE OFF 11
NONE OFF 13
Error Description
Green
Reversing valve
OFF
malfunction
Compressor has an
OFF
open circuit.
Outdoor ambient air
temperature is not
OFF
within the outdoor
unit's start up range
Frequency limiting
OFF
module temperature
OFF Power issue
Page 61
System Status
All system functions are
terminated except indoor fan.
Normal status indicator when unit
is turned off.
All system functions are
terminated except indoor fan.
Compressor speed automatically
adjusted to match conditions.
Troubleshooting for Possible
Causes
S Check input voltage on outdoor unit
terminal strip (N and L terminals). If
lower than 175 VAC, correct
voltage problem.
S Check reversing valve wiring
connection for damage.
S If voltage and wiring connections
are correct, replace reversing
valve.
S Check connections between com­
pressor and outdoor control (control
terminals are marked U, V and W).
Status indicator. System functioning
properly. Outdoor unit will not oper­
ate if outdoor ambient temperature is
out of range.
S Verify proper attachment of heat
sink.
S Clean heat sink, if necessary.
System power issue. See unit infor­
mation manual for further informa­
tion.
Corp. 1244-L9