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RP-HRPD-IOM (07-22) 132210-B
• Intermittent spark ignition safety pilot systems:
There are two types of intermittent 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 or with
lockout is option AH3 .
• Ignition controller:
As part of the intermittent safety pilot system, the ignition controller provides high voltage
spark to ignite 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 to complete the DC circuit and prove pilot flame . Proper operation of the electronic spark ignition
system requires a minimum flame signal of 0 .2 microamps, as measured by a microampmeter . With pilot flame
proven, the ignition controller energizes the main gas valve .
Burners and Carryover System
• Burners:
These duct furnaces have individually-formed steel burners with accurately die-formed ports to provide
controlled flame stability without lifting or flashback with either natural or propane gas . All burners are lightweight
and are factory-mounted in an assembly that permits all of the burners to be removed as a unit for inspection or
service .
NOTE: Natural gas burner racks (except when equipped with electronic modulation option AG39,
AG40, AG41, or AG42) are equipped with two flash carryovers. Propane gas burners are equipped
with one flash carryover and a regulated gas lighter tube system.
•
During regular service, check the main burner ports, the carryover assemblies, and the orifices for cleanliness .
OPERATION
⚠ WARNING ⚠
To ensure safety, follow the lighting instructions located on the outlet box cover.
Pre-Startup Checklist
Ensure that electrical supply is in accordance with voltage rating on unit’s rating plate .
Ensure that all field wiring is in accordance with wiring diagram and that wire gauges are as required for electrical
load .
Ensure that electrical entrances are sealed against the weather .
Ensure that fuses or circuit breakers are in place and are sized correctly .
Ensure that condensate drain holes in the corners of the cabinet are open .
Ensure that clearances from combustibles are in accordance with
Check piping for leaks and proper gas line pressure and bleed trapped air from gas lines (refer to
section):
a . Turn OFF manual shutoff valve .
b . Turn ON gas supply .
c . Observe gas meter for movement or attach pressure gauge readable to 0 .1 IN WC and, after turning gas ON
for 10 seconds, turn OFF gas supply—no change in pressure should occur over 3-minute period .
d . If step c indicates leak, locate leak by brushing soapy solution on all fittings—bubbles will appear at any leaks .
e . Repair any leaks and repeat test .
Check to ensure that flue discharge openings are free from obstructions .
