Daikin Sky Air R-407C - Low Outside Temperature Control in Cooling Operation (Year Round Cooling)

ESIE02–01 Overview of the cooling mode functions
Part 2 – Functional Description 2–33
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2.6 Low Outside Temperature Control in Cooling Operation
(Year Round Cooling)
Applicable units R(Y)P71-250
Purpose The purpose of the control is to prevent freezing of the indoor heat exchanger due to:
■ Drop of the low pressure
■ Indoor heat exchanger temperature (Te).
Method The method to control is reduction of the air flow volume of the outdoor unit fan.
Starting and ending
conditions
■ The control is not activated during start-up control.
■ The control is activated when the outdoor temperature drops below (41.7 - 0.84 x room suction
temperature). At this temperature, the outdoor fan speed switches to L-tap.
■ The differential for the return condition is 4 K.
Outside air
temp. (Ta)
(˚CDB)
Indoor suction
air temp. (Tr)
(˚CDB)
L tap range
H tap range
Ta < 45.7 - 0.84 x Tr
Ta > 41.7 - 0.84 x Tr
(H tap return condition)
(L tap condition)
21 37
-5
46
24
28
11
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