Step 1: Perform visual inspection.
With power off, make sure all wiring connections are clean and tight.
Turn on the power to the appliance and the S8910U.
Open the manual shutoff valves in the gas line to the appliance.
Test for a gas leak upstream of the gas control if the piping has been disturbed.
GAS LEAK TEST: Paint gas control gasket edges and all pipe connections upstream of the gas control with a rich
soap and water solution. Bubbles indicate gas leaks. Tighten the joints and screws or replace the component to stop
a gas leak. Recheck with soap and water solution.
Step 2: Verify control system ground.
The ignition module must share a common ground with the main burner. The burner serves as the common
grounding area to assure reliable flame detection. If there is not good metal-to-metal contact between the burner and
ground, run a lead from the burner to ground.
Step 3: Review normal operating sequence and module specifications. See Operation and Application sections.
Step 4: Reset the ignition module.
Turn the thermostat or controller to the lowest setting.
Turn on the system power.
Wait one minute.
As you do Steps 5 and 6, watch for points where operation
deviates from normal. Refer to Troubleshooting section to
correct the problem.
Step 5: Check the safety lockout operation.
Turn off the gas supply.
Set the thermostat or controller above the room temperature to call for heat.
Watch for igniter warmup following prepurge. Igniter starts to glow several seconds after it is powered.
Time the length of time gas control is energized; measure the time by connecting a voltmeter across the gas
valve terminals:
Selection tabs A and B for 4 seconds.
Selection tabs C and D for 7 seconds.
When using a three-trial ignition selection tab (tabs B or D), watch for the start of the 96-second between trial
purge, followed by a 34-second igniter warmup and a second try for ignition. After a third purge, warmup and
trial for ignition sequence, the S8910U should lock out. LED goes into one flash mode after lockout.
Open the manual gas control knob and make sure no gas is flowing to the burner.
Set the thermostat below the room temperature and wait one minute before continuing.
Step 6: Check normal operation.
Set the thermostat or the controller above the room temperature to call for heat.
Observe the light off sequence and make sure the main burner lights smoothly without flashback.
Make sure the burner operates smoothly without floating, lifting, or flame rollout to the furnace vestibule or heat
buildup in the vestibule.
Test for a gas leak downstream of the gas control if the piping has been disturbed. GAS LEAK TEST: Paint the
gas control gasket edges and all pipe connections downstream of the gas control with a rich soap and water
solution. Bubbles indicate a gas leak. Tighten the joints and screws or replace the component to stop a gas
leak. Recheck with soap and water solution.
Check the burner flame condition. The igniter-sensor or sensor must be constantly immersed in flame. Check
the burner flame condition as shown in Fig. 7. Do not relocate the hot surface igniter or flame rod.
Turn the thermostat or controller below the room temperature. Make sure the main burner and the pilot flames
go out.
WARNING
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