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Each unit is supplied with air inlet and discharge spigots.(see page 2 for sizes)
These may be used for connecting installers ducting or used with the optional duct, plenum and grille kits
(refer to kit instructions for installation)
NOTE: It is essential that ducting is adequately insulated to prevent sweating. An insulation thickness of at
least 45mm is recommended.
MAXIMUM PIPE RUNS
45m maximum including 6m lift. There will be no significant loss of capacity for extended pipe runs provided
pipes are correctly sized.
CALCULATING EQUIVALENT LENGTHS
The effects of bends and fittings must be taken into account.
Pipe sizes are based on:
Minimum of 2.5 m/s (500 fpm) suction gas velocity for horizontal or downflow.
Minimum of 5.0 m/s (1000 fpm) suction gas velocity for upflow.
Maximum of 20.0 m/s (4000 fpm) suction gas.
Where vertical risers exceed 3m, oil traps must be formed in the pipe. This will help ensure that oil returns to
the compressor. Typically fit an oil trap every 3m with a trap at the bottom of the riser.
GOOD PRACTICE
Keep pipe runs as short as possible.
Avoid sharp bends
Fully insulate both suction and liquid including mechanical connections
Try to avoid running pipes through hot areas.
The maximum pipe lengths to be used for each pipe size and outdoor unit are shown in the table below.
Use of these sizes and lengths is recommended in order to achieve optimum system performance. Smaller
suction line sizes may be used but will impose a loss in performance of approximately 2% per 1K additional
suction line pressure drop on total cooling and approximately 1% on sensible cooling.
DUCTWORK
PIPEWORK
Size
20
Liquid
3/8
Suction
3/8
30
40
50
60
3/8
3/8
3/8
3/8
1/2
1/2
1/2
5/8
6/11
80
1/2
5/8
54208007-06
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