Mitsubishi Electric PAA-A18AA1 Manual De Operación página 12

PAA-A18, 24, 30, 36, 42AA1/BA1/CA1
5. Operation
5.1. Balance points
The PAA unit automatically switches between heat pump heating and furnace heating based upon
configuration parameters and operational data.
The unit supports two outdoor temperature set points—Economic Balance Point and Capacity Balance
Point—that determine the most efficient method of heating.
5.1.1. Economic balance point
The Economic Balance Point is the outdoor temperature above which it is more efficient to heat with the
heat pump and below which it is more efficient to heat with the furnace.
The ideal Economic Balance Point will depend on the cost of the fossil fuel being used for the furnace, the
efficiency of the furnace, the cost of electricity, and the efficiency of the heat pump for heating based upon
various outdoor temperatures.
When the PAA unit is first used and the outdoor air temperature is above the Economic Balance Point, the
kit first tries to heat the space with the heat pump.
Below the Economic Balance Point, only the furnace is used for heating. Above the Economic Balance
Point, either the heat pump or furnace is used for heating.
To configure the Economic Balance Point, refer to the PAA unit installation manual.
5.1.2. Capacity balance point
In cold climates, when the PAA unit is sized for the cooling load rather than the heating load, the kit may
not have the capacity to heat the space using the heat pump even at temperatures above the Economic
Balance Point.
If the kit is unable to heat the space within approximately 24 to 29 minutes (due to insufficient heating
capacity at the current outdoor temperature), then the PAA unit switches to heating with the furnace. At this
point, the system has set the Capacity Balance Point.
During subsequent calls for heat, if the outdoor temperature is below either the Capacity Balance Point or
the Economic Balance Point, then only the furnace is used for heating. If the outdoor air temperature is
above both the Capacity Balance Point and Economic Balance Point, then the heat pump tries to heat the
space first.
Specifications are subject to change without notice. 12 © 2022 Mitsubishi Electric US, Inc.