Reznor RPBL Unit Installation Manual - Manual (Page 51)

Form I-SSCBL/RPBL, P/N 149159 R7, Page 51
8.9 Pilot and
Ignition
Systems
Ignition System - Natural gas units are equipped with a spark ignited intermittent
safety pilot system that shuts off the pilot gas flow between heat cycles. Propane units
(or as an option on natural gas units) require a lockout device that stops the gas flow to
the pilot if the pilot fails to light in 120 seconds. The lockout device has a 1-hour retry
or requires manual reset by interruption of the thermostat circuit. Refer to the wiring
diagram supplied with the unit for pilot system identification and proper wiring. Pilot
with lockout is Option AH3; non-lockout spark pilot is Option AH2.
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. With pilot flame proven, the ignition controller energizes the main gas valve.
Ignition Controller
with Lockout, UTEC
1003-514, P/N
257010, for Option
AH3 Gas Control
Recycling Ignition
Controller, UTEC
1003-638A, P/N
257009, for Option
AH2 Gas Control
Service NOTE: If replacing
an earlier model of ignition
controller, order replace-
ment kit P/N 257472 for
a unit with recycling gas
control Option AH2 or P/N
257473 for Option AH3 gas
control with lockout. (Option
codes are listed on the unit
wiring diagram.)
CAUTION: Due to high voltage on pilot spark wire and pilot electrode, do
not touch when energized. See Hazard Levels, page 2.
Pilot - All pilots are vertical, target type with lint-free feature. Pilot flame should be
approximately 1-1/4" in length. Pilot gas pressure should be the same as the supply
line pressure. Pilot gas is supplied through the combination valve; the pilot gas flow
is controlled by an adjustment screw located in the valve body. For maintenance, see
Paragraph 10.2.2.
8.10 Burners,
Orifices, and
Carryover
System
Burners - Individually formed steel burners capable of operating on either natural or
propane gas are used in this heater. These burners have accurate, machine-formed
ports to give controlled flame stability and operation without lifting or flashback. All
burners are lightweight and factory mounted in an assembly which permits all of the
burners to be removed as a unit for inspection or service.
Burner Carryover Systems (FIGURES 54 and 55) - All natural gas burners (except
when equipped with electronic modulation Option AG39, AG40, AG41 or AG42; see
Paragraph 8.8.4) are equipped with two flash carryover systems, one on each end of
the burner rack. ( NOTE: A natural gas burner rack on furnaces manufactured prior to
Series 6 had a gas lighter tube carryover and one flash carryover.)
Pilot
Auxiliary
Sensor
Flash Carryover
Flash
Carryover
FIGURE 54 - Natural Gas Burner Rack
Carryover Lighter Tube
Pilot
Carryover
Regulator
Flash
Carryover
Propane Pilot
Auxiliary
Flame
Probe
FIGURE 55 - Propane Burner Rack with Lighter
Tube
Natural Gas
Pilot
FIGURE 53 - Ignition
Controllers