POWER GAS BURNER START-UP

(Refer to Figure 9-1 to identify burner parts)

1.Remove the enclosure panel cover on the water heater or boiler to expose the control circuit. Located on the back side of this cover is a wiring diagram of the unit. This diagram will show the controls used in our circuitry.

2.Visually check to be sure all components are intact and no damage has occurred during transit.

3.Check all connections within the control cabinet. A loose connection on a component 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. Some burners have longer pre-purge periods. On a call for heat, the control is energized which starts the motor and begins a purge sequence. On completion of the purge cycle, the gas valve(s) opens and ignition occurs.

5.Remove flame safeguard control from its base. Check connections in the control mounting base. Again, loose connections can cause nuisance shutdowns. Also 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 removing the burner cover, exposing the nozzle assembly.

7.The L-Series burner must be removed from the heater and the blast tube removed to access the electrodes. The electrodes may be accessible by removing the nozzle assembly on larger burners. Free the nozzle assembly from the gas train by breaking the unions on the gas lines. Some models will use an orifice that is installed in these unions. Retain for re-use.

8.Next, remove the four bolts that hold the nozzle assembly to the burner housing. Once the nozzle assembly is free, pull it back slightly and remove the wires going to the flame and ignition rod. The easiest method of removing the nozzle assembly is to rotate it 90° upward and tilt slightly forward while working it towards you (see Figure 9-2). Be careful not to damage the electrodes.

9.With the electrodes exposed, check them for the proper settings as called for in Figure 9-3. Also 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 bracket retaining screw. Draw the electrodes out of the nozzle assembly through the

holes in the pressure plate.

PV500-9 04-2000

(2)

10.Inspect the electrodes for cracked ceramics or loose retaining studs that hold the wire within the ceramic. Using supplied metric Allen wrench, loosen one or two pressure plate retaining screws so that the plate rotates freely on nozzle hub. Push plate towards the nozzle assembly gas spider to ensure it remains fully back and level. Do not re-tighten retaining screws at this time. Select the proper pressure plate hole in which to place each electrode and insert the electrode through the hole, retaining stud end first. Place electrodes in the electrode mounting bracket between the mount and the retaining bracket.

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

NOTE: Electrodes may have a high temperature, electrically insulating tape around them. The tape is designed to cushion the ceramic insulators in the mounting bracket, but is not absolutely necessary, and may be removed if it interferes with the positioning of the electrodes.

12.Ensure electrodes are loose enough to be rotated and that they will slide back and forth in the mounting bracket with firm finger pressure.

13.While ensuring the pressure plate is in the previously described position, measure and set electrodes according to Figure 9-3. After the gaps and settings are complete, fully tighten the electrode mounting bracket retaining screw. Do not overtighten or the insulation may crack.

CAUTION: Electrodes may shift while tightening the screw due to rotation of the upper electrode mounting bracket. Holding down on this bracket while tightening the screw will stop this from happening.

NOTE: The pressure plate may rotate on the nozzle hub as the electrodes seek their position during the tightening of the electrode mounting bracket retaining screw. This is desirable to prevent the electrodes from binding and not seating properly in the mounting bracket. The electrode ceramics will crack, causing ground faults in the circuit if this condition exists.

14.After complete mounting and positioning of the electrodes is accomplished, rotate the pressure plate so that no portion of the plate touches the electrode ceramics at the holes the electrodes pass through in the plate (ream holes slightly larger if needed to obtain

Section 9