58
SSCBL-RPBL-IOM (10-22) 149159-C
OPERATION—CONTINUED
Pre-Startup Checklist
Ensure that suspension, mounting, clearances, and duct and venting connections are in accordance with
section .
Ensure that flue discharge and combustion air openings are free from obstructions .
Ensure that electrical entrances are sealed against the weather .
Ensure that gas supply pipe openings are sealed .
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 fuses or circuit breakers are in place and are sized correctly .
Ensure that clearances from combustibles are in accordance with
On units with option AG41 or AG42, ensure that heat stage controllers are set .
Check blower pulley and motor pulley to ensure that they are secure to their shafts . Check belt tension and
alignment . Check blower rotation (refer to
section) .
On units with optional dampers, ensure that damper linkage is in accordance with
section .
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 .
Startup
1 . Close all panels tightly .
2 . Turn ON electric and gas supply to furnace .
3 . Adjust thermostat or ductstat so that call for heat exists .
4 . Observe for complete sequencing of safety pilot and ignition (refer to
) .
Table 29. Sequence of Operation
Step
Action
Observe
1
Set thermostat at its lowest setting
2
Turn ON electric and main and manual gas valves
3
Set thermostat at desired
setting—thermostat calls for
heat
Venter motor is energized after 15-second (approximate) time delay
Venter flow switches from NC to NO contacts to energize pilot gas valve and spark gap to produce
pilot flame on each operating cycle
Sensing probe proves presence of pilot flame and energizes safety switch portion of control to de-
energize spark gap and energize main valve
Main gas ignites and unit fires at full rate
4
If flame is extinguished during
main burner operation, safety
switch closes main valve and
recycles spark gap
On unit equipped with controller with lockout, if pilot is not established within 120 seconds
(approximately), unit locks out for 1 hour unless reset by interrupting power to control circuit
Blower motor operates from fan time delay
5
Thermostat is satisfied
Solenoid gas valve, pilot gas valve, and ignition controller de-energized
Time delay relay keeps venter motor on for approximately 90 seconds (post-purge)
6
To shut down, set thermostat
to lowest setting
Blower motor remains on as determined by fan time delay
