Mitsubishi Electric City Multi PURY-HP-TKMU-A-H Manuel D'installation page 13

Precautions for outdoor unit combinations
Refer to [Fig. 9.2.2] for the positioning of twinning pipes.
[Fig. 9.2.2]
<A> Install the piping so that oil will not accumulate in the stopped outdoor unit. (high pressure side only)
Unit 1 Unit 2
1.
C
D
The NG example shows that oil accumulates because the units are installed on a reverse gradient while unit 1 is in operation, and unit 2 is stopped.
Unit 1 Unit 2
2.
Unit 1 Unit 2
h1
h1 = 0.2 m (7-7/8 in) max
The NG example shows that oil accumulates into unit 1 while unit 2 is in operation, and unit 1 is stopped. Vertical pipe height (h1) should be 0.2 m (7-7/8 in) or below.
3.
Unit 1
h2
h2 = 0.1 m (3-15/16 in) max
The NG example shows that oil accumulates into unit 1 while unit 2 is in operation, and unit 1 is stopped. Difference between unit and unit in height (h2) should be 0.1 m (3-15/16 in) or
below.
Unit 1
4.
h2
h2 = 0.1 m (3-15/16 in) max
The NG example shows that oil accumulates into unit 2 while unit 1 is in operation, and unit 2 is stopped. Difference between unit and unit in height (h2) should be 0.1 m (3-15/16 in) or
below.
<B> Slope of twinning pipes (high-pressure side only)
E
A
Downward slope
C
BC controller
E
Caution:
If a sight glass is installed, inexperienced technicians that use the glass may overcharge the refrigerant.
A
Unit 2
Unit 2
D
B
Upward slope
D
Twinning pipe
Unit 1 Unit 2
C
B
D
Unit 1 Unit 2
h1
h1 > 0.2 m (7-7/8 in)
Unit 2
Unit 1
h2
h2 > 0.1 m (3-15/16 in)
Unit 1
Unit 2
h2
h2 > 0.1 m (3-15/16 in)
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