Specifications

M-Series Sizing
Heating vs. Cooling
It is very important that all contractors follow proper procedure and size
units based on a Manual J calculation. A load calculation takes into
account all the factors that cause the building to lose heat in the winter
and gain heat in the summer. Some of the factors taken into consideration
are exposed walls, insulation, windows, doors, and even the direction the
building faces.
Inverter technology has changed the way heat pumps are used. Because
the inverter can vary the capacity of the system, we can now size units
based on the largest load, which in many cases may be the heat load.
When single speed compressors are sized on heat load and changed
over to cooling, the units can be grossly over-sized. The result is very little
dehumidification and comfort problems.
Using charts like the ones below from the technical service manual,
you can check the equipment capacity at the design temperatures for
heating and cooling. If these values fall within both the heating and
cooling capacity ranges of the system, you can select that system with
confidence.
MSZ/MUZ-FE09NA
HEATING CAPACITY
Outdoor
Temperature
Degrees (ºF)
-13.0 -4.0 5.0 14.0 23.0 32.0 41.0 50.0
Heating
Capacity
(Btu/h)
6,740 8,978 1,1216 13,453 15,090 16,469 17,848 21,338
Ratio 0.62 0.82 1.03 1.23 1.38 1.51 1.64 1.96
Percent
Heating
Capacity
62% 82% 100% 100% 100% 100% 100% 100%
COOLING CAPACITY
Indoor Air Outdoor intake air DB temperature (ºF)
IWB (ºF)
85 95 105 115
TC SHC TPC TC SHC TPC TC SHC TPC TC SHC TPC
71 10.3 6.5 0.63 9.7 6.1 0.68 9.0 5.6 0.72 8.3 5.2 0.75
67 9.7 7.4 0.60 9.0 6.8 0.65 8.4 6.4 0.69 7.7 5.8 0.72
63 9.1 8.1 0.58 8.5 7.6 0.62 7.7 6.9 0.66 7.0 6.3 0.69
Notes: IWB: Intake air wet-bulb temperature
TC: Total capacity
SHC: Sensible heat capacity
TPC: Total power consumption (kW)
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