Dougie Reid
DIY
- Reaction score
- 2
I have an original 250w glow plug in my 8yr old pellet boiler that's used to light the pellets during the start up phase on my boiler. The boiler has been tripping the fuse on around 50-60% of the start-up cycles. Using a bit of trial & error I think I've narrowed it down to the glow plug However, the following is confusing me: when I test the resistance of the glow plug using my multimeter I get a figure of around 211 ohms & no continuity. The voltage that goes to the glow plug when the boiler is simply switched on at the mains is around 30v, & increases significantly when I press the start cycle. All seems good yeah?
However, when I connect the glow plug & try to turn on the power to the boiler, the fuse trips. If the glow plug isn't connected the boiler, it switches on just fine (lcd display etc, not a full start cycle) & stays on. I tested the glow plug for continuity both whilst fitted & out of the boiler but there's no continuity!
How can the glow plug trip the fuse when it has resistance & no continuity? Could the glow plug have continuity & short out with the voltage applied on powering on but show resistance & no continuity with the tiny current from a voltmeter? Is this what could happen if has broken down inside. It's 8 yrs old after all. Thanks
However, when I connect the glow plug & try to turn on the power to the boiler, the fuse trips. If the glow plug isn't connected the boiler, it switches on just fine (lcd display etc, not a full start cycle) & stays on. I tested the glow plug for continuity both whilst fitted & out of the boiler but there's no continuity!
How can the glow plug trip the fuse when it has resistance & no continuity? Could the glow plug have continuity & short out with the voltage applied on powering on but show resistance & no continuity with the tiny current from a voltmeter? Is this what could happen if has broken down inside. It's 8 yrs old after all. Thanks