Daikin FTX25JVEA9 Service Manual page 171

System control
Regarding target superheated degree SH
(Example) The following example is based on room A.
Notes: 1. In Sky Air models, the indoor units are equipped with distribution capillary tubes ; therefore,
2. In Sky Air models, the heat exchanger intermediate position is provided on the liquid
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When the sum of heat exchanger temperature (DCA) and target superheated degree is
smaller than gas pipe lower limit temperature, the following condition is set: DSH = Gas pipe
lower-limit temperature – DCA.
When DLA < DCA (when liquid pipe temperature is exceeded due to heat exchanger
intermediate superheating), the motorized valve is opened based on the fixed value
determined by QRSHA = (0.12 Nm³/hr), with QRSHA being the flow rate operating amount
(relative value) provided by the SH control.
In normal condition (DLA ≥ DCA), when SHA = (DGA – DCA) – DSH and the previous value
is SHAZ QRSHA = 0.05 × ((SHA – SHAZ) + 0.32 × (SHA + SHAZ))
= 0.05 × (SHA – SHAZ) + 0.016 × (SHA + SHAZ)
Where QRSHA ≤ QHENCS, QRSHA = QHENCS1
the heat exchangers may superheat even when the condition is met.
connection pipe side; as a result, superheated condition is difficult to detect.
Si18-201
Main Functions