York R-410A Technical & Service Manual page 57

Outdoor
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D. Four-way valve: It is only available for cooling and heating system and change the refrigerant
flow direction.
E. Check valve: Prevents the refrigerant return back to the compressor and damaged the
compressor.
F. Electronic expansion valve: It is only available in heating mode to control system's
superheating and function as a capillary tube to decrease the refrigerant pressure and function
as throttle.
G. Electronic expansion valve: According to the capacity requirement of indoor unit adjust the
refrigerant flow volume.
H. High-pressure switch: Switches trip when preset pressure exceeds 3.3 +/- 0.1MPa, thus
stopping operation.
L. Low-pressure switch: Switches trip when the suction pressure is lower than 0.15 +/- 0.1MPa,
thus stopping operation.
M. Oil separator: Device that collected oil discharged from the compressor and returns it to the
compressor via oil return capillary. Also function as reservoir for holding exceeds oil.
N. Oil return capillary: Function as a way for discharged oil return to the compressor.
O. Outdoor heat exchanger: Exchange the heat with outdoors ambient
P. Indoor heat exchanger: Exchange the heat with indoor ambient
Q. Muffle and Filter: Decrease the noise and avoid other things blocked the indoor unit EXV.
R. Gas balance pipe: In the top of compressors to balance the suction pressure and guarantee
every compressor in the same system have the same refrigerant volumes.
S. Oil balance pipe: In the bottom of compressors to balance the oil level of every compressor in
system.
T. Check valve: It is only available in cooling mode to form a refrigerant loop.
U. Fixed compressor: On/off according to the capacity requirement of total indoor units
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