Capacity Setting Of The Pqfy - Mitsubishi Electric PQFY Installation Manual

8.3. Capacity setting of the PQFY

To allow for the maximum use of the PQFY-P140, it is indexed electronically as size 20, thus allowing the system to utilise the maximum cooling
•
capacity as it is expected that the PQFY will be ran mainly in heating and thus never conflict in terms of outdoor capacity with air handling fan
coils in cooling. However the refrigerant pipe work etc, should be sized as a size 140-fan coil. See unit specification.
HOWEVER THE OUTDOOR UNIT SHOULD BE SIZED TO THE MAXIMUM HEATING / COOLING CAPACITY REQUIRED.
•
Even though it is indexed as a 20 it still requires the heating / cooling capacity it was designed for.
e.g. 1
PUMY-P100VMH + 5 X P20 fan coils + PQFY-140
System Index is 120.
So long as the PQFY is never run at the same time as the fan coils the system will run with no problems. But if the fan coils run at the
same time as the PQFY i.e. in heating, the total heating capacity of the system will be a little over 12kW.
e.g. 2
PUHY-P250YGM-A can give up to 31.5kW of heating, if a PQFY-P140 (15kW of heating) is connected then the maximum capacity of
heating fan coils that can be running in heating at the same time as the PQFY is 16.5kW.
For this same purpose the PQFY-P250 is indexed electronically as a size 200, thus allowing the system to utilise the maximum cooling capacity of
•
DX fan coils. However the refrigerant pipe work etc should be sized as a size 250-fan coil.
THE ABOVE TWO EXAMPLES APPLY TO THE PQFY-P250 AS WELL. Nominally the PQFY will produce 25kW of water heating and therefore
•
require 25kW of heating from the outdoor unit.
16