Insulation Of Refrigerant Lines; Piping Size - Mitsubishi Electric PAAA18AA1 Installation Manual

• Store the piping to be used during the installation indoors, and keep both ends of the piping sealed until
just before brazing.
• If dust, dirt or water gets into the refrigerant cycle, the oil will deteriorate and the compressor may fail.
• Use refrigerant oil to coat flares and flange connections before connecting.
• The refrigerant used in the unit is highly hydroscopic and mixes with water which will degrade the
refrigerant oil.

11.1. Insulation of refrigerant lines

To avoid condensation, provide sufficient anti-sweating insulation to the refrigerant pipes and drain pipes.
When using commercially available refrigerant pipes, be sure to cover them with insulating material with
a heat-resistant temperature rating of more than 100°C (212°F). The recommended thickness of the
insulation can be found in the chart below. This applies to both the liquid and gas pipes. Insulate all indoor
pipes with polyethylene insulation with a minimum density of 0.03 and a thickness as specified in the table
below.
Pipe size
6.4 mm to 25.4 mm [1/4 to 1 in]
28.6 mm to 38.1 mm [1-1/8 to 1-1/2 in]
• If the unit is used on the highest story of a building and under high temperature and high humidity, it is
necessary to use thicker insulation than specified in the table above.
• If there are customer's specifications, please follow them.

11.2. Piping size

Model
PAA-A18AA1
PAA-A18BA1
PAA-A24AA1
PAA-A24BA1
PAA-A30AA1
PAA-A30BA1
PAA-A36BA1
PAA-A36CA1
PAA-A42BA1
PAA-A42CA1
1
When PUZ outdoor unit is connected, please use 3/8" pipe size with PAC‑493PI for the liquid pipe.
2
When PUZ outdoor unit is connected, please use 5/8" pipe size with PAC‑A456JP‑E for the gas pipe.
Specifications are subject to change without notice.
PAA-A18, 24, 30, 36, 42AA1/BA1/CA1
Liquid Gas pipe
pipe
1 2
1/4" 1/2"
1 2
1/4" 1/2"
3/8" 5/8"
3/8" 5/8"
3/8" 5/8"
3/8" 5/8"
3/8" 5/8"
3/8" 5/8"
3/8" 5/8"
3/8" 5/8"
63
Insulation thickness
> 10mm [7/16 in]
> 15mm [5/8 in]
Drain pipe
O.D. 32 mm (1-1/4)
O.D. 32 mm (1-1/4)
O.D. 32 mm (1-1/4)
O.D. 32 mm (1-1/4)
O.D. 32 mm (1-1/4)
O.D. 32 mm (1-1/4)
O.D. 32 mm (1-1/4)
O.D. 32 mm (1-1/4)
O.D. 32 mm (1-1/4)
O.D. 32 mm (1-1/4)
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