Boiler Fault Finder

Domestic hot water and primary micro switches

Domestic hot water and primary micro switches Reasons a domestic hot water and primary micro switch will fail to start: Switch contact faulty Damaged / loose wiring harness To test a domestic hot water and primary micro switch (on a demand): Electrically isolate boiler / system controls Set multimeter to continuity “buzzer” scale A continuity check of the wiring harness at the printed circuit board end will ascertain correct operation of switch and the integrity of wires also. No continuity present will be a complete new assembly (micro switch with wiring harness). Continuity between C and NC = ok Continuity between C and NO = faulty…

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