Toshiba Carrier MMDMMD-AP0120VHG2UL Installation, Operation And Maintenance Manual page 13

Vertical air handling unit
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Direct-expansion coils are shipped pressurized
with dry nitrogen. Release pressure from the coil
through valves in protective caps before remov-
ing caps.
Do not leave piping open to the atmosphere un-
necessarily. Water and water vapor are detri-
mental to the refrigerant system. Until the piping
is complete, recap the system and charge with
nitrogen at the end of each workday. Clean all
piping connections before soldering joints.
Failure to follow these procedures could result in
personal injury or equipment damage.
Refrigerant Piping
Refrigerant coils have liquid and suction
line connections through the front of the
cabinet. CAUTION: Use proper care when
brazing including use of heat sink (wet
cloth or other method) to prevent damage
to liquid line and suction line components
(see Figure 4b)
Size and install refrigerant lines in accord-
ance with the condensing unit manufactur-
er's instructions. Provide insulation on the
suction line, to prevent condensation. Pro-
vide insulation on the liquid line if unit to be
used for heat pump service or if otherwise
System Design Regulation
When connecting MMD units in the VRF
system (mix or all), keep indoor/outdoor
unit capacity ratio with the range of
50% to 135%. For other conditions, refer
to the VRF System standard piping design
Wrap AHU-side
piping with wet cloth
before brazing.
Connecting pipe size is shown in the following table.
loose with the air handler) so as to match the con-
necting pipe size for unit sizes 012 and 018.
Fig. 4b — Connection of Refrigerant
Piping—Brazing Details
Page 13 of 60
Be sure to use the reducer pipe (shipped
Apply brazing to
full circumference
MMD IOM 1.2 11-10-2020
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