AAON M1-011 - Manual (Page 32)

32
The ASC fitting will come installed by the factory.
Should you need to re-install the ASC fitting in the
field, then do so according to the following procedure:
9. Hot Gas Reheat
Although the evaporator reduces moisture content
from warm, moist air being conditioned, the space
thermostat is a dry bulb device and will not call for
refrigeration if outdoor and space temperatures are
mild but very humid and the space temperature is
satisfied. However, the humidity level may cause the
space to be uncomfortable. A reheat system is used
to correct this condition. To prompt operation of the air
conditioning system, a humidistat is required and to
avoid cooling the space excessively while removing
moisture, a coil which accepts discharge gas from the
compressor is located downstream of the evaporator.
The function of this coil is to heat the air that has been
cooled by the evaporator to approximate room
temperature. A reheat valve is installed in the
compressor discharge line to divert discharge gas to
the reheat coil when the humidistat calls for
dehumidification but returns all discharge gas to the
condenser when cooling is required.
Note: No additional piping is required for
modulating hot gas reheat!
Figure 9.1, AAON’s Modulating Reheat System
Condenser
Coil
Reheat Coil
Evaporator
Coil
Compressor
Reheat
Control
Valve
Control
Board
Supply Air
Sensor
Wiring to
Reheat Control
Valve
Suction Line
Liquid Line
Field Piping
Air Handling Unit
Condensing Unit
Evaporator
Coil
Air Handling Unit
Refrigerant Line
Connections
Suction
Hot Gas
Liquid TXV
Figure 8.3, HGBP Connection to Evaporator & ASC Fitting
Figure 8.4, ASC Fitting at
Distributor, Exploded View
Refrigerant Flow (Liquid)
Expansion Valve Outlet
Distributor Ring
Distributor Nozzle
Hot Gas Bypass Line
(From Condenser)
Refrigerant Flow
(Bypass Gas)
Distributor
Auxiliary Side
Connector (“ASC”)
ASC
1. Install nozzle and ring in ASC (orientation as shown)
– remove from distributor if necessary.
2. Install ASC on distributor inlet.
3. Install expansion valve on ASC inlet.
4. Install liquid line.
5. Install hot gas bypass line.