Trane RAUC-C20 Installation Operation & Maintenance page 32

Installation
Refer to
Liquid Line Moisture Indicator Sight Glass
To aid in troubleshooting, install a moisture indicator sight glass in the liquid line near the
evaporator, down stream of the solenoid valve prior to any branch takeoffs to the expansion valve.
The sight glass should not be used to determine adequate refrigerant charge or sub-cooling. Actual
temperature measurements are required to determine proper charge and sub-cooling.
Refer to
Liquid Line Solenoid Valves
Liquid line isolation solenoid valves are required for refrigerant migration control into the
evaporator during the "Off" cycle and should be connected as illustrated in the applicable field
connection diagram.
Under certain conditions, liquid line solenoid valves may be used to trim the amount of active
evaporator as compressors unload. Generally, the trim solenoid valve is unnecessary on comfort
cooling VAV systems, and is only required on CV systems when dehumidification is a concern.
Refer to
Thermostatic Expansion Valve (TEV)
Trane recommends a balance-ported externally equalized valve in order to maintain satisfactory
superheat control down to lower valve loading conditions and to compensate for pressure drops
between the expansion valve and superheat control point (evaporator refrigerant outlet).
In order to get proper refrigerant distribution into the coil, an expansion valve is required for each
coil distributor.
Access Valves (Ports)
The access ports in the liquid line allows the unit to be charged with liquid refrigerant and is used
to determine sub-cooling.
The access ports in the suction line allows the operating suction pressure to be checked across the
suction line filter. These ports are usually a Schraeder valve with core.
Ball Shutoff Valves
The ball shutoff valve allows for isolation of the Filter/Filter Drier for easier core replacement.
Two ball shutoff valves equal to the OD Tubing size for both the liquid line and suction line are
required.
Frostat™ Coil Frost Protection
The Froststat control is the preferred method of coil frost protection. The Frostat control bulb is
mechanically attached to the suction line near the evaporator and wired to the unit control panel.
Refer to the proper field connection diagram for details.
Table 5.
Capacity
Note: Use specific parts listed or equivalent. (Per Circuit)
32
Table 5 for filter/filter drier recommendations.
Table 6 for solenoid valve/moisture indicator sight glass recommendations.
Table 6 for solenoid valve/moisture indicator sight glass recommendations.
Filter/Filter Drier Recommendations
Suction Line
(Sporlan)
20 Ton RSF-4817-T
25 Ton RSF-4817-T
30 Ton RSF-4817-T
40 Ton RSF-4817-T
50 Ton RSF-4817-T
60 Ton RSF-4817-T
Filter Core Liquid Line
(Sporlan) (Sporlan)
RPE-48-BD
RPE-48-BD
RPE-48-BD
RPE-48-BD
RPE-48-BD
RPE-48-BD
Filter Drier Core
(Sporlan)
C-485-G RCW-48
C-487-G RCW-48
C-487-G RCW-48
C-485-G RCW-48
C-487-G RCW-48
C-487-G RCW-48
SS-SVX09A-EN