Lennox MS8 SERIES Installation And Service Procedures page 80

INTER-UNIT COMMUNICATION ERROR
APPLICABLE UNIT SIZE(S): All
APPLICABLE ERROR CODE(S): E6
See page 87 for procedure for testing
communication line.
The control
voltage
detection circuit
is at fault.
Is fault corrected?
Y
MS8C / MS8H (208-230V)
Y
Check inter-unit
wiring
Is cable
Y
(wires)
damaged?
N
Check communication circuit
N
of outdoor unit
Is there a
communication
circuit error?
N
Replace indoor or
outdoor control
Start
Did the system
operate normally
before the failure
occurred?
Replace outdoor
Y
control
N
Is fault corrected?
Y
End
FIGURE 89
Page 80
N
Verify inter-unit wiring using
the unit wiring diagram
Is connection
Y
correct?
N
Correct inter-unit
using unit wiring
diagram.
N
Is fault corrected?
Y