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10
Troubleshooting Refrigerant Pressure Problems
and Check Valves
Refer to Fig. 13, on page 8, and the Cooling Mode and Heating
Mode tables (Tables 2-4).
COIL METERING DEVICES (OUTDOOR COILS ONLY)
The metering devices are multiple fixed-bore devices (Accutrol)
brazed into the horizontal outlet tubes from the liquid header, lo
-
cated at the entrance to each evaporator coil circuit path. These
metering devices are non-adjustable. Service requires replacing
the entire liquid header assembly.
Check for possible blockage of one or more of these metering de
-
vices by creating a low load condition on the evaporator-function
coil and then observing the frosting pattern on the finned portion
of the coil.
To check the indoor coil, disconnect the supply fan signal or con
-
tactor (IFC) coil, then start the circuit in a Cooling Mode (jumper
R to Y1 or Y2) and observe the frosting pattern on the face of the
indoor coil. A frost pattern should develop uniformly across the
face of the indoor coil starting at each tube at the Accutrol nipple
locations.
To check the outdoor coil, disconnect the outdoor fan motor. Start
the circuit in a Heating Mode (jumper R to W1 or W2) and ob
-
serve the frost pattern on the face of the outdoor coil.
Failure to develop frost at an outlet tube can indicate a plugged or
a missing orifice.
Refrigerant System Pressure Access Ports
There are two access ports in each circuit - on the suction tube and
the discharge tube near the compressor. These are brass fittings
with black plastic caps. The hose connection fittings are standard
1
/
4
-in. SAE male flare couplings.
The brass fittings are two-piece high flow valves, with a receptacle
base brazed to the tubing and an integral spring-closed check
valve core screwed into the base. See Fig. 18. This check valve is
permanently assembled into this core body and cannot be serviced
separately. Replace the entire core body if necessary. Service tools
are available from RCD that allow the replacement of the check
valve core without having to recover the entire system refrigerant
charge.
Apply compressor refrigerant oil to the check valve core’s bottom
O-ring. Install the fitting body and torque to 96 ± 10 in.-lb (10.9 ±
1 Nm). Do not over-tighten.
Fig. 18 —
CoreMax
1
Access Port Assembly
1. CoreMax is a registered trademark of Fastest, Inc.
5/8
” HEX
0.47
30°
0.596
1/2-20 UNF RH
1/2
” HEX
45°
WASHER
O-RING
7/16-20 UNF RH
DEPRESSOR PER AHRI 720
+.01/-.035
FROM FACE OF BODY
This surface provides a metal to metal seal when
torqued into the seat. Appropriate handling is
required to not scratch or dent the surface.
SEAT
CORE
(Part No. EC39EZ067)
Summary of Contents for WeatherMaker 50TCQ 17-24 Series
Page 35: ...35 Fig 53 RTU Open Overlay for Economizer Wiring ...
Page 36: ...36 Fig 54 VFD Overlay for W2770 Controller Wiring ...
Page 68: ...68 Fig B 50TCQD17 24 Control Wiring Diagram APPENDIX D WIRING DIAGRAMS ...
Page 69: ...69 Fig C 50TCQD17 24 Power Wiring Diagram 208 230 3 60 Units APPENDIX D WIRING DIAGRAMS ...
Page 70: ...70 Fig D 50TCQD17 24 Power Wiring Diagram 460 3 60 575 3 60 Units APPENDIX D WIRING DIAGRAMS ...
Page 71: ...71 Fig E RTU Open Overlay APPENDIX D WIRING DIAGRAMS ...
Page 72: ...72 Fig F PremierLink Overlay APPENDIX D WIRING DIAGRAMS ...