Operation
On call for heat, the ignition system, consisting of an electronic spark module, gas pilot system is energized. Providing pilot is proven blower will start running, the main gas valve will open and the heater will operate. When the operating control is satisfied the heater will shut down.
Start-up Procedures (S8610B)
1.Turn on power to the heater with gas supply off.
2.Check ignition module as follows:
a.Set the thermostat or controller to call for heat.
b.Watch for continuous spark at the pilot burner.
c.Check the ignition spark operation. Time must be within the lockout timing period (15 or 90 seconds).
d.Turn control down to end call for heat and wait 60 seconds on lockout models before begin- ning step 3.
3.Turn on gas supply.
4.Set controller to call for heat.
5.System should start as follows:
a.Spark will turn on and pilot gas valve will open and the blower will begin running.
b.Heater will operate until call for heat is satis- fied.
Burner Adjustment
This burner assembly does not require any adjust- ments.
Visual Inspection
Flame can be observed through the slot opening above the plenum. Flame color is blue and evenly spread on the top surface of the burner. At least every three months a visual inspection should be made of the burners. In case flame lifting is observed on the burner, check gas pressure on manifold and static pressure in plenum. Gas pressure in manifold should be 3.9 in. WC and static pressure in plenum should be greater than 0.5 in. WC.
Electrical
Be sure that electrical service to the heater has over- load fuse or circuit breaker protection, wire size and connections that comply with all applicable codes.
High/Low Gas Pressure Switch
Pressure switch senses high/low pressure and auto- matically shuts down burner if abnormal pressure exists.
Fig. 30: Gas Pressure Switch
Fig. 31: Low NOx Burner Tray Assembly
Burner Drawer Removal
1.Shut off main electrical power switch to heater.
2.Shut off gas upstream of heater.
3.Remove front door.
4.Disconnect gas line from gas valve.
5.Remove (2) screws that mount burner tray to unit, and (4) screws that secure gas valve to jacket.
6.Disconnect wires that terminate at gas valve.
7.Unscrew (4) screws that secure the control box.
8.Disconnect pilot wire from the ignition module.
9.Disconnect wire harness from the combustion blower.
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