Reznor HRPD (Outdoor Duct Furnaces) Unit Installation Manual - Manual (Page 22)

Form I-RP/HRPD, P/N 132210 R14, Page 22
8.5 Pilot and
Ignition
Systems
8.0 Controls
(cont'd)
8.4 Gas Controls (cont'd)
8.4.5 Optional Electronic Modulation (cont'd)
Troubleshooting
Guides for Checking
Bypass Combustion
Air Damper Safety
Circuit with Option
AG39, AG40, AG41,
or AG42
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
Flash Carryover
FIGURE 16 - Burner
Rack with Spark Pilot
Main
Burner
Spark Pilot
The horizontal pilot is located in the control end of the burner rack and is accessible
after the control compartment panel has been removed. All pilots are target type with
lint-free feature. Pilot gas pressure should be the same as supply line pressure. (See
Paragraph 6.1.) If required, adjust the pilot flame length to approximately 1-1/4" with
pilot adjustment screw in control valve body.
Intermittent Spark Ignition Safety Pilot Systems - There are two types of intermit-
tent spark pilots -- one type shuts off the pilot gas flow between the cycles and the
other not only shuts off the pilot gas flow between cycles but also has a lockout device
that stops the gas flow to the pilot if the pilot fails to light in 120 seconds. This lockout
feature has a 1-hour retry or requires manual reset by interruption of the thermostat
circuit. Propane units installed in Canada require the spark ignition system with the
lockout device. Refer to the wiring diagram supplied with the heater for pilot system
identification and wiring. Spark pilot without lockout is designated as Option AH2; with
lockout as Option AH3.
CAUTION: Due to
high voltage on
pilot spark wire
and pilot electrode,
do not touch when
energized. See
Hazard Levels,
page 2.
Ignition Controller - As part of the intermittent safety pilot systems, the ignition con-
troller provides the high voltage spark to ignite the pilot gas and also acts as the flame
safety device. After ignition of the pilot gas, the ignition controller electronically senses
the pilot flame. A low voltage DC electrical signal is imposed on the separate metal
probe in the pilot assembly. The metal probe is electrically insulated from ground. The
pilot flame acts as a conduction path to ground completing the DC circuit and proving
pilot flame. Proper operation of the electronic spark ignition system requires a
minimum flame signal of .2 microamps as measured by a microampmeter. With
pilot flame proven, the ignition controller energizes the main gas valve.