AAON M1-011 - Manual (Page 33)

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After the room temperature thermostat is satisfied and
the humidistat continues to call for moisture removal,
the modulating valve will allow a controlled amount of
hot gas to enter the reheat coil. A discharge air
temperature sensor mounted within the air handling
unit provides input to an electronic control board. The
valve position is controlled to provide a specific supply
air temperature set point that is set on the control
board, or sent to the control board by a remote 0 to 10
VDC signal.
Since the controlled amount of hot gas is inserted into
the liquid line at the condensing unit, no additional
piping is necessary from the condensing unit. Only the
normal liquid and suction piping is required. The
modulating hot gas valve is factory mounted and
wired. The control board is shipped with a default
setting for a neutral discharge air temperature of 75
°F.
The only additional work required is to run the valve
control wires to the outdoor unit. The factory setting
can be overridden by connection to a 0 to 10 VDC
signal from another control system.
Unlike some other manufacturers’ cycling “on-off”
reheat control solenoid valve that are poorly regulated,
and produce unacceptable supply temperatures,
AAON’s modulating hot gas reheat system provides a
controlled supply air temperature, and will meet most
outside air requirements for handling enhanced latent
capacity. The system can be designed with the
outdoor air quantity to meet the design occupancy.
When used in a make-up air application, even up to
100%, the unit controller can maintain the neutral
supply air temperature under most conditions.
NOTE
IMPORTANT!
HGRH will always be on the 1
st stage
circuit only, and never on the second
stage circuit, when ordered on an
AAON condensing unit.
HGBP will always be on both 1
st and
2 nd stage circuits, and never only on
one circuit, when ordered on an AAON
condensing unit.
These rules apply even when HGRH
and HGBP exist together on the same
system.
10. HGBP & HGRH Together
See appendices A and B for individual
information about HGBP and HGRH.
If you still have questions about the
installation or operation of either HGBP or
HGRH after reading these sections, then
please contact your AAON Sales
Representative.
Figure 10.1, Components of Hot Gas Bypass & Hot Gas Reheat