Mitsubishi Electric PUHY-HP72 Service Handbook page 256

[8-12 Parts Replacement Instructions ]
2. L-module (four-way valve (21S4b))
Explained below is the procedure for replacing four-way valve (21S4b) (on the left when seen from the front of the unit).
Secure sufficient work space before starting maintenance work. (See 8-12-1 Ensuring Maintenance Space (Preparation for the
Maintenance of Refrigerant Circuit Parts).)
(19B) Follow the same procedures ((1) through (7), (8A), and (11A)) for replacing four-way valve (21S4a).
(20B) Remove the pipe below four-way valve (21S4b) and on the front by removing the braze at the two areas shown in
Figure 19.
Remove the rubber spacer.
Figure 19
(21B) Remove four-way valve (21S4b) by removing the braze from the area above four-way valve (21S4b) as shown in Figure
20.
Figure 20
(22B) To make it easier to connect four-way valve (21S4b), cut the pipe end below the raised hole (cut off the section covered
with brazing filler) on the pipe with a pipe cutter. Cut the pipe with narrowed end that is included with four-way valve
(21S4b) to the same length as the pipe that was removed from the on-site pipe. (See Figure 21.)
Figure 21
HWE18240_GB
Pipe diameter: φ19.05
ID of the pipe with a narrowed end: φ15.88
Cut the
pipe here.
Severed
pipe
L-module
After being removed, leave the pipes at the bottom
inside the unit.
(Once removed from the unit, it will be difficult to
re-place the pipes.)
A cap for sealing the refrigerant pipe
is included with four-way valve
(21S4b).
Replace the old cap with the one
included with the four-way valve.
Cut the pipe with a narrowed end that is
included with four-way valve (21S4b) so that
the section of the pipe excluding the narrowed
end will be the same length as the pipe that
was removed from the on-site pipe.
*The included pipe with a narrowed end is
100 mm long. Cut it to the appropriate
length.
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chapter 8 -