Mitsubishi Electric PUHY-RP-Y(S)JM-B, Data Book

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79
7. UNIT SELECTION
OUTDOOR UNITS
(3) Obtaining the unit capacity
(4) Notes
A. If the apportioned indoor unit capacity obtained in step 5) on the previous page is equal to or greater than the rated
indoor unit capacity, the following formula will be used to calculate the indoor unit capacity: "Rated capacity x return air
temperature correction factor x piping length correction factor (x pipe diameter correction factor)".
B. If the apportioned indoor unit capacity obtained in step 5) on the previous page is smaller than the rated indoor unit
capacity, the following formula will be used to calculate the indoor unit capacity: "Apportioned indoor unit capacity x
return air temperature correction factor."
* The standard outside air temperatures used to obtain the return air temperature correction factor is 35ºCDB for cooling
and 6ºCWB for heating.
* If non-standard size pipes are connected, use the pipe diameter correction factors for the main pipes, merge pipes, and
branch pipes.
When deciding the outside air temperature to calculate unit capacity requirements, take into consideration the possible
temperature rise around the outdoor unit due to short-cycling. (When installing outdoor units collectively on the rooftop or if
outdoor units are surrounded by walls or other objects, it is recommended to set the outside temperature as 43ºC for
calculation.)
If you want to take sensible heat load into consideration, refer to the relevant catalogs for information on sensible heat
factor when selecting indoor units.