Trane 120 GEH manual Features and Benefits, Hot Gas Reheat option, Common Reheat Applications

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Features and Benefits

Hot Gas Reheat (option)

For space conditioning and climate con- trol, Trane provides an accurate and cost effective dehumidification control through a hot gas reheat option. This option is designed to accommodate unit sizes 012, 036, 060 and 072 through 240.

With this reheat option, the return air from the space is conditioned by the air-to-refrigerant coil, then reheated by the reheat coil to control not only the space temperature, but to also reduce the relative humidity of the space. The moisture removal capability of a specif- ic heat pump is determined by the units latent capacity rating.

When operating in the reheat mode (meaning the sensible temperature has been met in the space), the humidistat signals the reheat relay coil to energize, allowing the high pressure refrigerant gas to flow from the (1) compressor, through the (2) reheat valve, into the

(3)reversing valve, or through the (4) reheat coil for dehumidification (See Figure 19). A switching relay has been provided for the reheat application to adjust the blower motor from normal operation to low speed when hot gas reheat is energized.

Note: Trane places an air separation space between the air-to-refrigerant coil, and the reheat coil to allow for maximum moisture removal.

Common Reheat Applications

The hot gas reheat option is designed to support building applications requir- ing fresh-air ventilation units delivering unconditioned-air directly to the space. It also provides dehumidification to large latent load spaces such as audito- riums, theaters and classrooms, or any- where humidity control is a problem.

Proper Hot Gas Design

The factory installed hot gas reheat option is only available with Deluxe or ZN524 controls packages.

A high static blower motor option will be required to support the hot gas reheat option for the 1/2 through 5 ton equipment.

Water regulating valves should not be used with the hot gas reheat option. Trane places a thermal expansion valve on all water-source heat pumps, as well as ground-source heat pumps, to regu- late refrigerant flow vs. water flow, making the heat pump more efficient to run.

Water-source heat pumps with hot gas reheat should not be used as a make- up air unit.

Figure 19: Hot gas reheat heat pump option.

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