MAXIM

AXIAL FLOW GAS BURNER START-UP

(Refer to Figure 17-2, page 6 to identify burner parts)

1.Remove the enclosure panel cover on the water heater or boiler to expose the control circuit. A wiring diagram, included in this packet, will show the controls used in our circuitry.

2.Visually check that all components are intact and no damage has occurred during transit.

3.Check all connections within the control cabinet. A loose connection could cause intermittent shutdowns.

4.Some burners will use direct spark ignition. They may use a single gas pressure regulator and gas valve or multiple valves and regulators. On a call for heat, the motor starts, the gas primary control is energized, and after a short delay (pre- purge) the gas valve(s) opens and ignition should occur.

NOTE: Do not tamper with or readjust program dipswitch settings. This will cause the control to become inoperable. Damage resulting from tampering will be excluded from coverage under the warranty of this unit.

5.Remove the flame safeguard control from its base. Check the connections in control mounting base; loose connections can cause nuisance shutdowns. Check the time card or programmer, when applicable, for good connection.

NOTE: Always secure gas lines and tag "Out of Service" before servicing burner nozzle or electrodes.

6.Pull the nozzle assembly to check the flame and ignition electrodes. This is done by first disconnecting the gas train by breaking at the unions. Then removing the nozzle assembly which will have the electrodes and pressure plate attached. Disconnect the electrode wires and take care not to damage the insulation on the electrodes.

7.With the electrodes exposed, check them for the proper settings as called for in Figure 17-3, page 8. Check for any hairline cracks in the insulators. Should replacement of burner electrodes be required, certain procedures must be followed. In all cases, removal of the electrodes is accomplished by loosening the electrode mounting clamps. Draw the electrodes out of the nozzle assembly through the holes in the pressure plate.

8.Inspect the electrodes for cracked ceramic or loose retaining studs that hold the wire within the ceramic. Select the proper pressure plate hole to place each electrode and insert the electrode through the hole, retaining stud end first.

9.Tighten electrode mounting clamp slightly until electrode ceramics are seated firmly and completely in the mounting bracket without gaps between ceramics and mounting bracket at the bearing faces.

10.Measure and set electrodes according to Figure 17-3, page 8. After the gaps and setting are complete, fully tighten the electrode mounting clamp. Do not overtighten or the insulation may crack.

11.Replace nozzle assembly; be sure to connect the flame and spark rod wires before installing nozzle assembly fully into blast tube. Check connectors on the ends of the flame and spark rod wires for good contact. Look for properly stripped wire ends. Be sure connectors are firmly attached to the flame and ignition rod ends. Insulating boots can give a false feeling of proper seating. DO NOT MOVE ELECTRODES. Be careful not to bump electrodes. Check fan wheel for free rotation.

12.Reinstall orifices in unions (if required). Reinstall gas nozzle assembly.

PV500-17 05-2000

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Section 17