Reznor RXH (Outdoor PreevA) Unit Installation Manual - Manual (Page 56)

Form I-RDH/REH/RHH/RXH (12-14), Page 56
FIGURE 49 - FX06 in
D12B, D12C, D12D, D12E,
and D12G
NOTE: For explanation on the
settings and functions of the
FX06 programmable control,
see Form CP-PREEVA-D12
B/C/D/E/F/G. If the unit being
installed has a special FX07
controller, contact your Rep-
resentative or the factory for
control information.)
Digital Control (FX06)
Applications by Control
Option Code
Side View - REH
Airflow
SCR Control
and Heatsink
Locations
Blower Electrical Electric
Heat
Section
DANGER
High voltages are present on
the terminals of the SCR power
controller(s).
SCR Power
Control and
Heatsink in
Option D12D
(one or two
required
depending
on amps)
FIGURE 50 -
Locations of
the SCR Power
Controls with
Heatsinks used
on Model REH
with Modulating
Heat Control
Option D12D
WARNING
The heatsink on the SCR power controllers is HOT
to the touch.
• Alarm and equipment shutdown features
• Service/Commissioning Test Mode
• Integrated timer functions for cooling and heating
There are four buttons that can be used for adjusting setpoints, viewing unit status, and
enabling unit test or shutdown modes. The controller display will indicate unit status
(on, off, or alarm), discharge air temperature, outdoor air temperature, dewpoint, and
enthalpy. When equipped with a wall-mounted sensor (Option CL67), space tempera-
ture will be displayed.
When the unit is called to operate, the main blower will run continuously in occupied
mode and intermittently in unoccupied mode. The unit operates based on the four Dis-
charge Air Temperature Setpoints listed below:
1. Standard (Neutral) Heating Discharge Air Temperature Setpoint
2. Space Heating Discharge Air Temperature Setpoint
3. Standard (Neutral) Cooling Discharge Air Temperature Setpoint
4. Space Cooling Discharge Air Temperature Setpoint
The heating and cooling equipment will cycle to maintain the active discharge air tem-
perature setpoint for occupied and unoccupied modes. Heating and cooling may be
locked out of operation based upon outdoor air temperature and enthalpy conditions.
If equipped with reheat, the control will also activate the dehumidification circuit to
maintain a neutral discharge air temperature setpoint and related dewpoint based
upon outdoor air and space conditions.
Option D12B - applies to RDH - Control is factory programmed for electronic modu-
lation gas heating, with 3-stage cooling, and with or without optional dehumidification
(reheat). Space reset control is optional.
Option D12G - applies to RDH and RHH - Control is factory programmed for elec-
tronic deep modulation gas heating, with 3-stage cooling, and with or without optional
dehumidification (reheat). Space reset control is optional.
Option D12C - applies to RDH, RHH, and RXH (no heat) - Control can be fac-
tory programmed for two-stage gas heating, with 3-stage cooling, and with or without
optional dehumidification (reheat). Space reset control is optional.
Option D12E - applies to REH - Control is factory programmed with neutral air control
for 2-stage electric heat, with 3-stage cooling, and with or without optional dehumidi-
fication (reheat). Space reset control is optional. NOTE: Option D12D is not recom-
mended for makeup air applications.
Option D12D - applies to REH - Control is factory programmed with recirculating
control for electric heat with SCR modulation, with 3-stage cooling, and with or without
optional dehumidification (reheat). Space reset control is optional.
Model REH units with Option D12D have additional controls to provide the electric
heat modulation. Depending on their size (amp draw), REH units with Option D12D are
equipped with one or two SCR power controllers. To provide comfort level heating in
response to the system controller, the SCR controllers cause modulation of specified
8.0 Controls and
Operation
(cont’d)
8.3 Digital Controls
(cont’d)
8.3.2 Optional Digital Heating/Cooling/Dehumidification (Reheat)
Controls, Options D12B, D12C, D12D, D12E, D12G (cont’d)