Reznor RPB Unit Installation Manual - Manual (Page 30)

Form I-RPB, P/N 131782 R11, Page 30
8.1.3. Optional 2-Stage Operation - Makeup Air Application
Optional Ductstat with Capillary Tubing (Option AG3) - The ductstat illustrated in
FIGURE 30A is used with Option AG3. The control is set to 70°F and has an adjust-
able range with a fixed differential of 3°F. Due to different CFM settings and outside air
temperatures, the average downstream outlet temperature may not match the ductstat
setting exactly. After the installation is complete, adjust the setpoint of the ductstat to
achieve the desired average outlet air temperature.
Optional Ductstat with Electronic Remote Setpoint Module (Option AG15) - The
sensing probe is field-wired to a remote temperature selector with a temperature
operating range to 130°F. The sensing probe and remote modules ( FIGURE 31) are
shipped separately for field installation. Follow the instructions in Paragraph 6.4.2 for
installing the sensor. Refer to the wiring diagram with the unit and the manufacturer's
instructions for wiring and installing the remote modules. Follow the wiring diagram
with the unit and the manufacturer's instructions for wiring and installation.
See
FIGURE 31. There will be one module for selecting temperature and one-stage
adder module.
8.1.4 Optional
Electronic Modulation
The type and capability of the electronic modulation system depends on the option
selected. Electronic modulation options are identified by a suffix to the Serial No.
printed on the heater rating plate. AG7 is identified as MV-1; AG8 is identified as MV-3;
AG9 is identified as MV-4; AG21 is identified as MV-A; AG39 is identified as MP-1; and
AG40 is identified as MP-2.
Installation NOTE: Sizes 350 and 400 with electronic modulation require a minimum
of 6" w.c. natural gas supply pressure.
8.0 Controls
(cont'd)
8.1 Gas Controls
(cont'd)
FIGURE 30B -
Ductstat Bulb
in Option AG3
(factory installed)
FIGURE 30A - Ductstat Control
in Option AG3
Factory
set at
70°F
Adjustable range
0-100°F with a fixed
differential of 3°F.
Ductstat Sensor Bulb
- Option AG3
FIGURE 31 - Remote Temperature Selector (A)
and Stage-Adder Module (B) In Gas Control
Options AG15
(A)
CAUTION: Be sure heat/cool selector
switch is set at "Heat" position.
(B)
Electronic Modulation
between 50% and 100%
Firing Rate (Options
AG7, AG8, AG9)
Depending on the heat requirements as established by the thermistor sensor, the
burner modulates between 100% and 50% firing. The thermistor is a resistor that
is temperature sensitive in that as the surrounding temperature changes, the Ohms
resistance changes through the thermistor. This change is monitored by the solid state
control center (amplifier) which furnishes varying DC current to the modulating valve
to adjust the gas input.
Each modulating valve is basically a regulator with electrical means of raising and
lowering the discharge pressure. When no DC current is fed to this device, it functions
as a gas pressure regulator, supplying 3.5" w.c. pressure to the main operating valve.
Refer to the wiring diagram supplied with the furnace for proper wiring connections.