40
I-SCE (09-18) PN207697R9
PRE-STARTUP CHECKLIST—CONTINUED
Blower Checks
Check blower pulley and motor pulley to ensure that they are secure to shafts; check belt tension and alignment
(refer to Belts, Blowers, and Drives)
Check blower rotation (refer to Belts, Blowers, and Drives)
Verify removal of all shipping supports (refer to Uncrating/Unpacking)
Check damper linkage (refer to Optional Dampers and Controls)
STARTUP CHECKLIST
Close all panels tightly
Turn ON electric and gas supply to furnace
Adjust thermostat or ductstat so that call for heat exists; observe for complete sequencing of safety pilot and ignition
Ensure complete sequencing of furnace operation as follows:
a. Set thermostat at its lowest setting
b. Turn ON electric and gas supply to furnace
c. Turn ON manual gas valves
d. Set thermostat at desired setting; thermostat calls for heat:
(1) Venter motor is energized after 15-second (approximate) time delay
(2) Venter flow switches from N.C. to N.O. contacts to energize pilot gas valve and spark gap to produce pilot
flame on each operating cycle
(3) Sensing probe proves presence of pilot flame and energizes safety switch portion of control to deenergize
spark gap and energize main valve
(4) Main gas ignites and unit fires at full rate
(5) If flame is extinguished during main burner operation, safety switch closes main valve and recycles spark gap
NOTE: On units equipped with a controller that includes lockout control, if the pilot is not es-
tablished within 120 seconds (approximately), the unit locks out for 1 hour or must be reset by
interrupting the power to the control circuit (refer to lighting instructions on unit).
e. Blower motor operates from fan time delay
f. Thermostat is satisfied
(1) Solenoid gas valve deenergized
(2) Pilot gas valve deenergized
(3) Ignition controller deenergized
(4) Time delay relay keeps venter motor on for approximately 1 minute (post-purge)
g. To shut down, set thermostat to lowest setting; blower motor remains on as determined by fan time delay
POST-STARTUP CHECKLIST
Observe burner flame at full fire. Natural gas flame should be about 1-1/2 inches in height with blue coloring.
Propane gas flame should be approximately the same height with blue coloring. Yellow tipping may appear on
propane gas. If yellow extends beyond 1/2- to 3/4-inch, adjust air shutters (refer to Burner Air Shutters). If shutter
adjustment does not reduce yellowing, check for gas leaks at the control manifold or orifice fitting.
Turn the unit OFF and ON, pausing 2 minutes between each cycle. Observe to verify smooth ignition. On two-
stage or modulating burner systems, manipulate temperature adjustment slowly up and down to see if control is
sequencing or modulating properly. Raising temperature setting drives burner on or to full fire.
Using a manometer or slant gauge readable up to 14 IN WC, check orifice manifold for operating pressure on
full fire. Natural gas should be 3.5 IN WC at this point. Propane gas should be 10 IN WC at this point. Variations
from these pressures are not recommended, as ignition and efficiency performance can be adversely affected
by improper pressure adjustment (refer to Gas Piping and Pressures).
If the system is equipped with an optional dirty filter switch, refer to Optional Dirty Filter Switch for instructions
to set the switch.
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