11
Apply compressor refrigerant oil to the check valve core’s
bottom O--ring. Install the fitting body and torque to
96
10 in--lbs (10.9
1 Nm). Do not over--tighten.
o
o
C08453
Fig. 17 -- CoreMax Access Port Assembly
THERMOSTATIC EXPANSION
VALVE (TXV)
All 50TCQ’s have a factory installed nonadjustable
thermostatic expansion valve (TXV). The TXV will be a
bi-flow, bleed port expansion valve with an external
equalizer. TXVs are specifically designed to operate with
Puron
R
refrigerant, use only factory authorized TXVs.
See Fig.18.
TXV Operation
The TXV is a metering device that is used in air
conditioning and heat pump systems to adjust to changing
load conditions by maintaining a preset superheat
temperature at the outlet of the evaporator coil. The
volume of refrigerant metered through the valve seat is
dependent upon the following (see Fig. 19):
1. Superheat temperature is sensed by the cap tube
sensing bulb on the suction tube at outlet of the
evaporator coil. This temperature is converted into
pressure by refrigerant in the bulb pushing downward
on the diaphragm which opens the valve using the
push rods. As long as this bulb and cap tube contain
any liquid refrigerant, this temperature is converted
into suction pressure pushing downward on the
diaphragm, which tends to open the TXV valve
through the push rods.
2. The suction pressure at the outlet of the evaporator
coil is transferred through the external equalizer tube
to the underside of the diaphragm.
3. The needle valve on the pin carrier is spring loaded,
exerting pressure on the underside of the diaphragm.
Therefore, the bulb pressure equals evaporator
pressure (at outlet of coil) plus spring pressure. If the
load increases, the temperature increases at the bulb,
which increases the pressure on the top side of the
diaphragm, pushing the carrier away from the seat,
opening the valve and increasing the flow of
refrigerant. The increased refrigerant flow causes
increased leaving evaporator pressure which is
transferred through the equalizer tube to the underside
of the diaphragm. This causes pin carrier spring
pressure to close the TXV valve. The refrigerant flow
is effectively stabilized to the load demand with a
negligible change in superheat.
Содержание 50TCQD17-D24
Страница 36: ...36 C10818 Fig 51 RTU OPEN Control Module 50TCQ ...
Страница 46: ...46 APPENDIX IV WIRING DIAGRAMS cont C150373 Fig 52 50TCQ D17 Power Wiring Diagram 208 230 3 60 ...
Страница 47: ...47 APPENDIX IV WIRING DIAGRAMS cont C12399 Fig 53 50TCQ D17 Power Wiring Diagram 460 3 60 575 3 60 ...
Страница 48: ...48 APPENDIX IV WIRING DIAGRAMS cont C12686 Fig 54 50TCQ D24 Power Wiring Diagram 208 230 3 60 ...
Страница 49: ...49 APPENDIX IV WIRING DIAGRAMS cont C12401 Fig 55 50TCQ D24 Power Wiring Diagram 460 3 60 575 3 60 ...
Страница 51: ...51 APPENDIX IV WIRING DIAGRAMS cont C160005 Fig 57 RTU OPEN Control Diagram ...
Страница 52: ...52 APPENDIX IV WIRING DIAGRAMS cont 50HE500891 F 50HE500751 J Fig 58 PremierLinktWiring Diagram ...