Immersion & Horstmann Timer Tripping MCB

[jaydebruyne]

Went to a job the other day and installed a new horstmann timer with boost function.

Cylinder has 2 immersions which I tested and both came up with a good reading (20ohms).

Have had a recall on the job as the MCB keeps tripping.

I'm gonna retest both immersions and stats tomorrow incase the immersions are overheating, will double check the programmer times too just in case they're overlapping and running both immersions at the same time but just wondered if anyone can shout some likely causes as to why it might be tripping..

 

[gassafe]

Maybe a immersion on its way out? Or dripping / slow leak onto live connectors

 

[LaMont5way]

Could be anything, faulty Mcb, damaged cable, burnt out switch, maybe best to have an electrician in and test from the board if not the immersion elements or stats.

 

[townfanjon]

Dont go on just ohms pal, the immersion may have blown, water and lecky dont mix

 

[jaydebruyne]

Dont go on just ohms pal, the immersion may have blown, water and lecky dont mix

You do continuity also?

 

[townfanjon]

Yep but continuity doesnt actually help every time , if the immersion heater blows, the white powder stuff ( sorry dont know what its called ) surrounds and packs the very thin conductor , so in other words it will show its got continuity , but if the conductor is open to the water , bang , it trips. Its a bit hard to explain , but the next immersion heater you take out hacksaw through the element and you will see what I mean.
Thinking again on this problem, if this job just trips every now and then , it probably isnt blown , if it blows everytime its turned on , it probably is .

 

[LaMont5way]

You do continuity also?

You have already done a continuity test if you have a ohms reading. You could do another continuity test between the element and earth(the cylinder). In my opinion I wouldn't expect much from this test though if your element reading is spot on. If think the other poster was referring to a 'megger' insulation test, which is really what you want to be doing.

 

[jaydebruyne]

You have already done a continuity test if you have a ohms reading. You could do another continuity test between the element and earth(the cylinder). In my opinion I wouldn't expect much from this test though if your element reading is spot on. If think the other poster was referring to a 'megger' insulation test, which is really what you want to be doing.

I don't have a megger 🙁 I've sworn not to buy any more tools for a while too 🙁((((

 

[jaydebruyne]

Yep but continuity doesnt actually help every time , if the immersion heater blows, the white powder stuff ( sorry dont know what its called ) surrounds and packs the very thin conductor , so in other words it will show its got continuity , but if the conductor is open to the water , bang , it trips. Its a bit hard to explain , but the next immersion heater you take out hacksaw through the element and you will see what I mean.
Thinking again on this problem, if this job just trips every now and then , it probably isnt blown , if it blows everytime its turned on , it probably is .

I'll know more tomorrow but to be honest I'm probably gonna drain down and change both immersions and rewire with fresh heat resistant flex.. At least if it trips again I'll know to get a sparky in as itll be an issue between the spur and the consumer unit.

 

[lame plumber]

been caught out before on one of these when the immersion is failing, now I jusr replace them to be on the safe side

 

[jaydebruyne]

been caught out before on one of these when the immersion is failing, now I jusr replace them to be on the safe side

Yeah I'm gonna do the same

 

[townfanjon]

Jay , if i get a pain in the a*** one, disconnect heater from timer existing supply etc and keep some 2.5 flex wire it up to heater and stat, put a plug on the other and bung it in a socket. If it goes bang , the heaters knact, if it heats and 'draws' its something else . BE CAREFUL

 

[jaydebruyne]

Jay , if i get a pain in the a*** one, disconnect heater from timer existing supply etc and keep some 2.5 flex wire it up to heater and stat, put a plug on the other and bung it in a socket. If it goes bang , the heaters knact, if it heats and 'draws' its something else . BE CAREFUL

Ive got a feeling its the bottom immersion so I might disconnect the top and connect the bottom to the sour and bypass the timer, see what happens..

I say all this but I'll still probably just drain down and change both elements and rewire them...

 

[lame plumber]

so much easier in the long run, saves going back 3 days later

 

[townfanjon]

Sarah Milican caught up with you yet lol

 

[jaydebruyne]

Sarah Milican caught up with you yet lol

Haha she's got a long journey by foot to catch up with me 😉

 

[jaydebruyne]

This was the bottom immersion!!!! No wonder it tripped.. Thanks for all the help guys 🙂

 

[townfanjon]

Lol, yep I think we can safely say that was the problem lol

 

[jaydebruyne]

Lol, yep I think we can safely say that was the problem lol

Yup haha I saw the white powder you were talking about too... And all was still attached by a thin copper thread so I guess that's where the ohms reading came from...??!!

 

[townfanjon]

Yep and it would have obviously shown continuity .
One fool proof way , as mentioned length of 2.5 with a plug , bunged in a plug socket .

 

[jaydebruyne]

Yep and it would have obviously shown continuity .
One fool proof way , as mentioned length of 2.5 with a plug , bunged in a plug socket .

Well, its a learning curve 😉 I learned. Can't say fairer than that 😉