Mitsubishi Electric CITY MULTI PUHY-P72-432TNU-A Data Book page 199

13. OUTDOOR INSTALLATION
13-3-7. Twinning on the outdoor unit side
See the following drawing for connecting the pipes between the outdoor units.
<In case of 2units combination>
<In case of 3units combination>
On-site piping
Twinning Kit
CAUTION
The length of the straight pipe must be 500mm[19-11/16 in.] or longer.
If not, it may cause improper operation.
MEES23K040
Twinning Kit
On-site piping
Twinning Kit
Y-Series
196