Lennox MMDA048S4-1P User Manual

Lennox Mini-Split Service Manual / Page 227
P0 Flowchart
P6
Check whether the voltage range of
P-N on IPM module is normal? DC277-
356V for 18-27KBtu/h; DC277-410V for
36KBtu/h
Check whether the connecting wiring
between main board and the IPM module
is connected tightly.
Yes
Yes
No
Check whether the
input power supply
is correct? 208-
230V, 1PH, 60Hz
No
No
Correct the incom-
ing power problem,
then check whether
the system operates
normally
Check whether the
power supply line
is connected cor-
rectly and tightly.
No
Connect it correctly
and tightly, check ok
or not?
Yes
No
Check whether
the lines in E-part
box are connected
tightly.
No
Connect it tightly,
check ok or not?
NoYes
Check whether the bridge
rectifi ers are normal? Use
the multimeter to measure
the resistance between each
two terminals, check whether
there is the condition that
value of resistance is 0.
Replace the bridge
rectifi ers.
No
Yes
Check whether the wiring of
each reactor is correct? If the
wire is broken, the resistance
of the two ports is ∞(models
except for M4OC-36HRFN1-
M& M4OC-36HRDN1-M);
Check whether the PFC
module broken (for M4OC-
36HRFN1-M& M4OC-
36HRDN1-M)
Replace the wir-
ing or reactor or
replace the PFC
module(for M4OC-
36HRFN1-M)
No
No
Connect it tightly,
unit operates cor-
rectly?
No
Yes
Replace the IPM
module, check
whether the
system works
normally.
No
Check if the out-
door fan runs prop-
erly or the outdoor
unit ventilation is
good.
For AC fan models, please
refer to 9.4 Trouble Crite-
rion Of Main Parts, check
whether the resistance of
the fan motor is normal. If
not, replace the fan motor.
For DC fan models, refer
to the solution of fan speed
malfunction (E8) . Find out
the cause and repair it.
Yes
No
Replace the main board;
check whether the system
operates normally?
No
Yes
Replace the compressor,
check whether the system
operates normally?
Problem Solved
Yes
Yes
Yes
Check whether the connecting wiring to
the compressor is connected correctly
and tightly
Connect it tightly,
check ok or not?
No
Yes

Lennox MMDA048S4-1P Specifications

General

Brand	Lennox
Model	MMDA048S4-1P
Category	Air Conditioner
Language	English