Lennox MMDA048S4-1P User Manual

Lennox Mini-Split Service Manual / Page 258
Heating Mode
Normally the system will choose the running fan
speed according to ambient temperature:
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$ '&B)$1B+,B63'B$''
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Electronic Expansion Valve (EXV) Control
1. EXV will be fully closed when turning on the
power. Then EXV will be standby with 350P open
and will open to target angle after compressor starts.
2. EXV will close with -160P when compressor
stops. Then EXV will be standby with 350P open and
will open to target angle after compressor starts.
3. The action priority of the EXVs is A-B-C-D.
4. Compressor and outdoor fan start operation only
after EXV is initialized.
Cooling mode
The initial open angle of EXV is 250P, adjustment
range is 100-350p. When the unit start to work for
3 minutes, the outdoor will receive indoor units( of
capacity demand) T2B information and calculate the
average of them. After comparing each indoor’s T2B
with the average, the outdoor gives the following
modifi cation commands: If the T2B>average, the
relevant valve needs more 16p open; If the T2B=
average, the relevant valve’s open range remains;
If the T2B<average, the relevant valve needs more
16p close.
This modifi cation will be carried out every 2 minutes.
Heating mode
The initial open angle of EXV is 250P, adjustment
range is 100-350p. When the unit start to work for
3 minutes, the outdoor will receive indoor units (of
capacity demand) T2 information and calculate the
average of them. After comparing each indoor’s T2
with the average, the outdoor gives the following
modifi cation commands: If the T2>average+2, the
relevant valve needs more 16p close;
If average+2≥the T2≥ average-2, the relevant valve’s
open range remains;
If the T2<average-2, the relevant valve needs more
16p open.
This modifi cation will be carry out every 2 minutes.
Four-Way Valve Control
In heating mode, four-way valve is opened. In
defrosting, four-way valve operates in according to
defrosting action. In other modes, four-way valve
is closed. When the heating mode to other modes,
the four-way valve is off after compressor is off
for 2 minutes. Failure or protection (not including
discharge temperature protection, high and low
pressure protection), four-way valve immediately
shuts down.

Lennox MMDA048S4-1P Specifications

General

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