Trane 120 GEH manual Features and Benefits, Schrader Connections 1/2 to 5-ton, Expansion Valve

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Features and

Benefits

Figure 11: Schrader connections

Figure 12: Water connections - small ton

Figure 13: Water connections - large ton

Figure 14: Thermal expansion valve

Schrader Connections: 1/2 to 5-ton

The connections for the low and high side of the refrigeration system are located directly beside the control box at the front, service access panel. See Figure 11 for schrader connection lotion.

Co-axial Water-to-Refrigerant Coil

The unit’s internal heat exchanging water coil is engineered for maximum heat transfer.

The copper or cupro-nickel seamless tubing is a tube within a tube design. The inner-water tube contains a deep fluted curve to enhance heat transfer and minimize fouling and scaling. It is available in either copper or cupro-nickel (selectable option) coil.The outer refrig- erant gas tube is made from steel mate- rial. The coil is leak tested to assure there is no cross leakage between the water tube and the refrigerant gas (steel tube) coil. Co-axial heat exchangers are more tolerant to freeze rupture. See Figure 11 for co-axial water coil.

Compressor and Co-axial Coil Isolation: 1/2 to 5 ton

Vibration isolation of the compressor and co-axial water coil is accomplished by increasing the rigidity and stiffness at the base. The platform provides double isolation to the compressor and single isolation to the co-axial water coil for additional attenuation during compres- sor start and stop.

Water Connections: 1/2 to 5-ton

The water-in/water-out connections to the co-axial water coil are located on the right-hand chamfered corner of the unit. The fittings are mounted flush to the chamfered wall to help limit shipping damage.

The water connection devices are con- structed of copper or bronze material and include a National Female Pipe

Thread (NFPT) junction. The connections are attached to the unit’s chamfer corner to alleviate the need for a back-up wrench during installation. See Figure 12 for water connection device.

Water Connections: 6 to 20-ton

Water hookups for the 6 through 20 ton units are located internal to the equip- ment to help alleviate damage to the water copper during shipment or job storage of units prior to installation. Each unit (although dual circuited) con- tains a single supply and return water connection. See Figure 13 for large ton- nage water hook-up, model GEV. Fittings for the supply and return are internally threaded.

Expansion Valve

All Trane water-source systems include an expansion valve flow metering device. This thermal expansion valve (TXV) allows the unit to operate with an entering fluid temperature from 25 F (3.9

C)to 110 F (43 C), and entering air tem- peratures from 40 F (4.4 C) to 90 F (32 C). The valve is designed to meter refriger- ant flow through the circuitry to achieve desired heating or cooling.

The expansion valve device allows the exact amount of refrigerant required to meet the coil load demands. This precise metering by the TXV increases the effi- ciency of the unit.

Reversing Valve

A system reversing valve (4-way valve) is included with all heating/cooling units. This valve is piped to be energized in the cooling mode to allow the system to provide heat if valve failure were to occur. Once the valve is energized for cooling, it will remain energized until the control system is turned to the OFF posi- tion, or a heating cycle is initiated.

Units with the cooling only option will not receive a reversing valve.

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