Spark electrode(s)

Spark electrode(s)

Reasons spark electrode(s) will fail to start:

  • Cracked ceramic insulation (causing leakage)
  • Poor terminal connections
  • Incorrect spark gap between electrode(s) or between electrode and burner/target
  • Electrode tip damaged / corroded / eroded
  • Damaged ignition leads
  • Burnt out / failing spark generator

On some boilers, it may be difficult to visually see the ignition electrode(s) to ascertain if they are sparking correctly or even at all.

Where this may be the case, always check the spark generator first for correct voltage readings (if possible, as not all boilers have remote spark generators, instead they are permanently fixed on the main p.c.b., where a new board will be required in this instance).

To test spark electrode(s):

240v Warning Sign240 V LIVE TEST

  • Electrically isolate boiler / system controls
  • Isolate gas supply beneath boiler
  • Carefully remove spark electrodes from burner assembly
  • With the gas left off, turn on electrical supply
  • Ensure the electrode tips are pointed away from the burner area but the electrode base (near to lead connection) is touching the outer burner area to ensure adequate earthing
  • Call for a hot water or central heating demand:

Sparking occurs –

  • May be faulty gas valve (needs further investigating)

No sparking occurs –

  • Incorrect gap at electrode tips (commonly 3mm-5mm)
  • Faulty spark generator (measure AC voltage across connections – will vary depending on manufacturer but should be in the region of 170 V AC or above)
  • Faulty electrode leads (check continuity)
  • Faulty electrodes (check continuity)

Note: If the gasket between the electrode base and the burner assembly appears to be worn / damaged when removing the electrodes for inspection, then both the gas supply and the electrical power supply must be isolated to prevent use – this would be AN IMMEDIATELY DANGEROUS SITUATION as products of combustion may enter the room.

Got the right tools for your trade?