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8.
IMPORTANT: If an electrical defect occurs after installation of the appliance; preliminary earth continuity,
polarity, and resistance to earth checks should be carried out with a multimeter. On completion of any
maintenance/fault-finding task that has required the breaking and remaking of electrical connections, then
checks of continuity, polarity, and resistance to earth must be repeated.
NOTE: When purging or checking gas supplies ensure that, there is adequate ventilation to the room or
cupboard, and all naked lights are extinguished.
SYMPTOM
a. Pilot fails to light.
b. Pilot fails to remain lit. i
c. Main burner fails to
light
d. Insufficient hot water. i. Burner operation cycle too short
f. Water temperature
outside usable range.
IMPORTANT: If a faulty heater control may have resulted in excessively high water temperatures, (above 85ºC,
185ºF), the hot water cylinder should be checked to establish whether it is a SELF-PRIMING type. If so, the circuit
should be drained and refilled to ensure that the air seal between the primary and secondary circuits in the cylinder is
properly established.
DEFECT DIAGNOSIS
POSSIBLE CAUSE
i
No gas supply to water heater.
ii Gas supply not purged.
iii Pilot injector orifice restricted.
iv Piezo faulty.
Thermocoulpe defective.
ii Pilot flame out of adjustment.
i. OFF button accidentally depressed.
ii Thermostat overheat.
iii Thermostat defective.
due to incorrect plumbing.
i. Thermostat out of calibration.
ii. Gas rate incorrect.
iii Thermostat phial or capillary
damaged.
RECTIFICATION
Check for gas at inlet pressure test point on
Multifunctional control.
Purge gas supply pipe in accordance with BS6891.
Clean or replace pilot assembly.
Check/replace piezo unit, lead or pilot burner assembly.
Replace pilot burner assembly.
Adjust pilot flame adjusting screw to provide pilot flame
of approximately 15mm long and just enveloping
thermocouple tip.
Press 'OFF' button, wait for loud click (approx 3
minutes) and repeat lighting procedure.
Draw off hot water from system to allow thermostat to
cool, and ensure burner lights.
Replace Multifunctional control.
Check plumbing, in particular lateral runs.
Set thermostat for required water temperature or replace
Multifunctional control.
Check burner pressure, main injector for blockage,
replace main injector if faulty.
Replace Multifunctional control.
10
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