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• U1, Y1 Types
When an External Air Intake Flange (ø100) is in Use
External Air Intake Volume and Resistance and 
Operation Noise Characteristics within the Unit
Calculate the operation noise when external air is being fed by combining the noise when only external air 
is being fed as shown in the graph for operation noise characteristics and the operation noise of the unit as 
stipulated in the catalogue.
The operation noise conforms to JIS standards and constitute measurements taken in an anechoic chamber 
1.5 m directly beneath the indoor unit. Under normal circumstances, the values shown here are greater owing 
to the effects of surrounding noise and reverberation when the unit is actually installed.
With the External Air Intake Flange Attached
Resistance within the Unit (Pa)
External Air Intake Volume (m
3
/h)
Noise with only External 
Air Intake dB(A)
Operation Noise 
(External Air Intake Only)
Duct (ø100) for Connecting 
the External Air Intake Flange
0
0
10
20
30
20
30
40
50
40
50
60
70
80
90
100
5
10
15 2018
U1 Type Y1 Type
The operation noise for models that use small units is lower, so use values that are within the range shown 
in the above table. Using values that exceed these will result in noise when only external air is fed being 
louder than the noise emitted from the unit.
Type
Permissible Air Intake 
Volume (m
3
/h)
36
13
45
15
50 7160 100 125 140
15 17 18 18 18 18
The amount of external air that is possible to feed when it is fed directly into the unit (ø100)
NOTE
SM830211-07PAC-i.indb294SM830211-07PAC-i.indb294 2013/09/1722:47:592013/09/1722:47:59