# Rocket Cellini v2 tripping RCD on fuse box



## hullcity (Feb 5, 2014)

Hi all,

Switched on the Rocket this morning only for the RCD on the fuse box to trip immediately. Tried again and the same thing happened, the power led flicked on for a split second before the RCD tripped again. Opened up the Rocket, no sign of any damp/water leakage, wires all look ok. I unplugged the wires at the heating element, switched on again and this time the power led came on, the water pump started up and the RCD did not trip. Resistance across the heating element terminals measures 44 Ohm.

Any advice on how to proceed with the troubleshooting would be greatly appreciated.

Thanks and stay healthy,

Mike


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## Alfieboy (Dec 26, 2018)

hullcity said:


> Hi all,
> 
> Switched on the Rocket this morning only for the RCD on the fuse box to trip immediately. Tried again and the same thing happened, the power led flicked on for a split second before the RCD tripped again. Opened up the Rocket, no sign of any damp/water leakage, wires all look ok. I unplugged the wires at the heating element, switched on again and this time the power led came on, the water pump started up and the RCD did not trip. Resistance across the heating element terminals measures 44 Ohm.
> 
> ...


 Hi Mike

Turn off the power - Disconnect the element completely - Do you get any reading between a terminal and the metal of the casing or boiler?

Neil


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## hullcity (Feb 5, 2014)

Thanks for your help Neil,

Did as you suggested, I don't detect any short circuit between either element terminal and the case or boiler.

Mike


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## DavecUK (Aug 6, 2013)

hullcity said:


> Thanks for your help Neil,
> 
> Did as you suggested, I don't detect any short circuit between either element terminal and the case or boiler.
> 
> Mike


 The problem is that it can be very difficult to detect anything that way...as the element heats, there can be more current transmitted between it and earth, so they test good when cold but leak enough to trip the RCD when hot. A megger is the only fairly sure way to test it.

Best thing is to change the element.


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## hullcity (Feb 5, 2014)

Thanks Dave,

Since the RCD trips immediately when I switch the machine on, wouldn't the element still be cold? Any other simple troubleshooting I can do with a multimeter?

Mike


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## DavecUK (Aug 6, 2013)

hullcity said:


> Thanks Dave,
> 
> Since the RCD trips immediately when I switch the machine on, wouldn't the element still be cold? Any other simple troubleshooting I can do with a multimeter?
> 
> Mike


 The inner core within it will heat up immediately, there there is damp in the MgO filling and a slight hole, that can be enough to track 30mA, probably less, depending on how far from the tripping point the RCCBO is already....depends what else is on the ring e.g. computers

You can try switching the meter to the megohm range and see what reading you get.


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## hullcity (Feb 5, 2014)

Thanks again Dave,

Well, for what it's worth, if I set the range on my multimeter to 2000kohm, I get a reading of around 120 between a heating element terminal and the boiler body.

Mike


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## DavecUK (Aug 6, 2013)

hullcity said:


> Thanks again Dave,
> 
> Well, for what it's worth, if I set the range on my multimeter to 2000kohm, I get a reading of around 120 between a heating element terminal and the boiler body.
> 
> Mike


 That will do it.... and worst that can happen if I'm wrong is you have a spare heating element. 😉


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## hullcity (Feb 5, 2014)

Thanks for your advice Dave. I'll get a heating element ordered and will report back with the results.

Cheers,

Mike


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## hullcity (Feb 5, 2014)

Finally got a new heating element, installed it this morning and voila, machine working again 😀. Once more thanks for your help.

cheers,

Mike


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## DavecUK (Aug 6, 2013)

hullcity said:


> Finally got a new heating element, installed it this morning and voila, machine working again 😀. Once more thanks for your help.
> 
> cheers,
> 
> Mike


 Glad it's working again....I would imagine a close inspection of the old element might show a pinhole or swelling somewhere


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