Marstair 526 HL Series, Technical Manual, Page: 10 / 31

-10-
B
60
A 10
C
D
E
MOUNTING HOLES
417
397
425
MOUNTING: MCU(+) 130 - 165 and MHPUE 100 - 130
All dimensions are
in millimetres.
MODEL A B C D E Weight (kg)
MCU(+) 130 1000 1020 495 251 100 101
MCU(+) 165 1000 1020 495 251 100 103
MHPUE 100
1000 1020 495 251 100 101
MHPUE 130 1000 1020 495 251 100 102
APPLICATION
1. To maximise performance, pipe runs should be kept as short as possible, avoiding sharp bends. However,
individual pipe runs to a maximum of 80m, including 20m lift, are permissible provided good refrigeration practice is
followed.
Published performance duties are based on 7.5m pipe runs. Correctly sized pipes for each installation, and fitting
the correct expansion orifice (restrictor) will result in no significant loss of capacity on extended pipe runs.
a) Pipe sizes are based on:-
Minimum of 3.8 m/s (750 fpm) suction gas velocity for horizontal or downflow.
Minimum of 7.6 m/s (1500 fpm) suction gas velocity for upflow.
Maximum of 15.2 m/s (3000 fpm) suction gas.
b) 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.
2. Add 25 grams of refrigerant oil (Polyolester Oil) for every 350 grams of charge added to systems with pipe runs
exceeding 25m, up to a maximum of 300 grams; preferably by slowly pumping into the suction side with the unit
running, after charging the system.
3. The maximum pipe lengths to be used for each pipe size and outdoor unit are shown in the table opposite. Use of
these sizes and lengths is recommended in order to achieve optimum system performance.