Reznor RPB Unit Installation Manual - Manual (Page 32)

Form I-RPB, P/N 131782 R11, Page 32
Sizes with AG39&40 Startup Cold Equilibrium at Full Rate Factory Setting
125-225 -1.3" w.c.±0.2 -1.05" w.c.±0.1 -0.58" w.c.±0.05
250-400 -1.2" w.c.±0.2 -0.95" w.c.±0.1 -0.58" w.c.±0.05
Wiring and Service -
AG39 and AG40
For wiring, consult the wiring diagram attached to the furnace. All wires in the electrical
box connecting the modulation controls must have a temperature rating of 150°C.
This is a unique system which includes custom-built components and custom settings.
If service is required, follow the general troubleshooting guide on page 38 and the
special troubleshooting guide below.
Computer Controlled
Electronic Modulation
between 20-28%,
Option AG40
natural gas Model RPB
only; not available on
Size 350
With this option the furnace is equipped with a Maxitrol signal conditioner (See FIG-
URE 32A) which accepts an input signal of either 4-20 milliamps or 0-10 volts from a
customer-supplied control device such as a computer. With the dip switches on the
conditioner in the "on" positions, the conditioner accepts a 4-20 milliamp signal. In
the "off" positions, the conditioner accepts a 0-10V signal. The conditioner converts
the signal to the 0 to 20 volt DC current required to control the modulating valve. The
heater functions and is equipped in the same way as for Option AG39 except that with
computer control the temperatures are selected through the field-supplied software
and there is no temperature selector or duct sensor.
reducing airflow through the burner. Safety switches monitor the position of the bypass
damper. When the gas pressure increases above 1.1" w.c., the bypass damper closes.
Combustion Air Pressure Switch Setting with AG39 and AG40
This uniquely designed modulation system requires combustion air pressure settings
different from the standard system. The approximate settings for the combustion air
proving switch at sea-level operation are:
Sensor Location The duct temperature sensor and mixing tube are shipped loose for field installation in
the dicharge duct. See Paragraph 6.4.2 for instructions on locating the sensor in the
ductwork.
The sensor for Opiton AG40 is field suppleid. Follow the guidelines in Paragraph 6.4.2
and the manufacturer's instrucitons.
Troubleshooting Guides for
Checking Bypass Combustion
Air Damper Safety Circuit on
Model RPB with Option AG39
or Option AG40
Is there 24 volts
between Terminal 2 on #1
Time Delay Relay and
Terminal 7?
Go to
Troubleshooting
Chart for heater.
Is there 24 volts
between Terminal 84 and
Terminal 7?
Is the
damper open?
Is there voltage
between Terminal 88 and
Terminal 7?
Is there voltage
between Terminal 4 on
ignition permissive relay and
Terminal 7?
Replace #1 time delay relay.
Replace ignition
permissive
relay.
Check combustion
damper lower end switch
adjustment. If necessary,
replace end switch.
Is there voltage
between Terminal 87 and
Terminal 7?
Check combustion
damper lower end switch
adjustment. Replace end
switch if necessary.
Place a jumper across
Terminal 86 and Terminal 7.
Did the
damper close?
Replace motor run
time delay relay.
Replace combustion
damper gear motor.
Replace primary
manifold
pressure switch.
YES
NO
YES NO YES
NO
YES
NO
YES
NO
NO
YES
YES NO
General Instructions: For each
step, check to ensure that the
wiring is not defective and that the
wiring connections are secure.
Symptom - Part 1:
Main burners are inoperative.
Assumes that 24 volts is
available between Terminal 2
and Terminal 7.
Symptom - Part 2:
Steady call for heat -
burner cycles.
Assumes constant
voltage between
Terminals 11 and 7 and
Terminals 2 and 7.
Measure manifold
pressure
during burner cycling.
When the
manifold pressure is
BELOW 1.0" w.c., is there a steady
voltage between Terminal 95
and Terminal 7?
Replace secondary
manifold pressure
switch.
While the
burner is cycling, is
there a steady voltage
between Terminal 84 and
Terminal 2?
Replace the primary manifold pressure switch.
When the
manifold pressure is
ABOVE 1.5" w.c., is there a steady
voltage between Terminal 95
and Terminal 7?
Replace secondary
manifold pressure
switch.
Is there voltage
between Terminal 4 of the
ignition premissive relay and
Terminal 7?
Replace ignition permissive relay.
YES
NO
YES
NO
YES
NO
8.0 Controls
(cont'd)
8.1 Gas Controls
(cont'd)
8.1.5 Optional Electronic Modulation (cont'd)