Immersion Heater Tripping Out RCB

Seweryn

Hi All,

Our old immersion heater has been working fine for years, but since Wednesday it keeps tripping out the ELCB the moment it is turned on. I replaced the timer, but no luck, same thing happens. I also disconnected the earth cable at the heating element, but still no result. It looks like the heater itself may be faulty, but I would like to make sure that there is nothing else, like the thermostat or the bath/sink on/off switch (or cable?). I have a multimeter, so can measure resistance, but not sure what figures are right between which terminals.
Any tips appreciated.

brightspark

replace the heater, without a megger you can't really test it. But it's almost always the element!

Seweryn

brightspark wrote: »

replace the heater, without a megger you can't really test it. But it's almost always the element!

Thanks.
Not great news so. I assume need to drain the water, etc. Any special tools needed and how much is the heater approximately?

Littlehorny

Changed our 12 year old immersion a couple of weeks ago. It cost 27 euro. I didnt empty the tank but turned off the supply to tank and ran the hot tap in bath to drain. Use a proper immersion spanner and when you get the spanner good and square give the handle of the spanner a few soft taps to free it up, be very careful!!! An old tank can tear very easily. Put a towel down at the bottom of the tank to catch any water that spills out when you are taking out old immersion, a couple of cupfuls of water will spill. As has been said earlier unless you are competent to do this job also remembering electricity is involved then get a pro to do it.
Best of luck with the job anyway!

Seweryn

Littlehorny wrote: »

Changed our 12 year old immersion a couple of weeks ago. It cost 27 euro. I didnt empty the tank but turned off the supply to tank and ran the hot tap in bath to drain. Use a proper immersion spanner and when you get the spanner good and square give the handle of the spanner a few soft taps to free it up, be very careful!!! An old tank can tear very easily. Put a towel down at the bottom of the tank to catch any water that spills out when you are taking out old immersion, a couple of cupfuls of water will spill. As has been said earlier unless you are competent to do this job also remembering electricity is involved then get a pro to do it.
Best of luck with the job anyway!

Thank you for that. I will try to do the job myself. It looks like a simple enough task, but just need the special spanner with the heater .

DublinDilbert

Looks like yous is an insulated tank so you will probably need the box type spanner as the regular one won't go onto it. Your plumbing wholesaler will sell these for very little money...

Robbie.G

Seweryn wrote: »

Thank you for that. I will try to do the job myself. It looks like a simple enough task, but just need the special spanner with the heater .

Be very careful with this if you mess it up you could be looking at a new cylinder which would cost hundreds.
Someone will supply and fit the immersion for around €120-€150
Your going to buy a tool that you will probly never use again and the cost if the heater so its your risk for the sake of saving a few quid

Seweryn

Robbie.G wrote: »

Be very careful with this if you mess it up you could be looking at a new cylinder which would cost hundreds.
Someone will supply and fit the immersion for around €120-€150
Your going to buy a tool that you will probly never use again and the cost if the heater so its your risk for the sake of saving a few quid

Thanks for the advise. It makes sense all right, I may get a quote from a local plumber and let him do it.

Littlehorny

Seweryn wrote: »

Thanks for the advise. It makes sense all right, I may get a quote from a local plumber and let him do it.

I borrowed the spanner from an electrician who lives on the road so if you know any plumbers maybe you can borrow one, not alot of electricians will have them i think. Looking at your photo the foam insulation is nice and tight to the immersion ring so thats good but as already warned careful is the word.:)

Seweryn

Thanks Guys. All sorted now .

I visited my local Co-op today where I surprisingly got a replacement heater for the boiler. Asked for the spanner and was kindly offered one for the job ("bring it back when you are done" - Thank you very much, me says :cool:).

So now all sorted, new heater in, wired up, new switch, new timer, old cable though. Got some hot water pipes insulated when I was at it.

Thanks again.

brightspark

Well done, I've heard a lot of stories if it going wrong (some electricians I know won't even remove their own elements!), glad yours worked out ok.

Hope you tightened all connections well, including the earth.

Seweryn

brightspark wrote: »

Well done, I've heard a lot of stories if it going wrong (some electricians I know won't even remove their own elements!), glad yours worked out ok.

Yep, gave it a few gentle knocks with a hammer to loosen the thread a bit. Took the time to make sure it will come off and it did, not forced it extensively. Then gently knocked through the hammer and finally managed to undo the heater. The rest was easy back on with a new gasket, etc.

brightspark wrote: »

Hope you tightened all connections well, including the earth.

Oh yeah, I am very particular when it comes to connections and wiring. Earth well connected, same as all other wires in the switch and timer. I ended up using the old earth bolt connector at the heater, as it was a better design with a sort of bowl type washer for holding the wire better together. The other reason to reuse the old cable was that it was a larger size, so obviously better. Connection points were all clean, no issues there.

lucernarian

Our immersion heater had failed recently (when switched on it tripped earth immediately) but this was only about a year and a half since it was last replaced. Are there any immersion heaters that can be expected to last a little longer than that?

dodzy

To_be_confirmed wrote: »

Our immersion heater had failed recently (when switched on it tripped earth immediately) but this was only about a year and a half since it was last replaced. Are there any immersion heaters that can be expected to last a little longer than that?

I would expect any immersion element to last way longer. I've done a good few for friends / relations and they were all in situ in excess of 10yrs. Mine has not been changed in 20yrs and is still working away.

Billy Bunting

To_be_confirmed wrote: »

Our immersion heater had failed recently (when switched on it tripped earth immediately) but this was only about a year and a half since it was last replaced. Are there any immersion heaters that can be expected to last a little longer than that?

What made the lat one go ?? I would be looking for cause.

brightspark

To_be_confirmed wrote: »

Our immersion heater had failed recently (when switched on it tripped earth immediately) but this was only about a year and a half since it was last replaced. Are there any immersion heaters that can be expected to last a little longer than that?

Are you in a very hard water area?

MajorMax

Sorry to hijack the thread, but I have a problem. My Immersion switch blew and I installed a new switch. Ever since, the immersion will work for about 45 minutes, then the fuse for the sockets will trip. Any ideas why this would happen?
Cheers

brightspark

MajorMax wrote: »

Sorry to hijack the thread, but I have a problem. My Immersion switch blew and I installed a new switch. Ever since, the immersion will work for about 45 minutes, then the fuse for the sockets will trip. Any ideas why this would happen?
Cheers

Going to need some clarification.

By fuse, do you mean the MCB or the RCD.

Is it cutting the power to all your sockets, or just some?

Is it cutting the power to the immersion also?

Was you replacement switch wired exactly the same as the old one?

A photo of the 'fuse' and of the switch would help.

lucernarian

Yes, a very hard water area though I hoped there would be some brands or models that would last longer than 18 months... The longest we've had one last has been 6 years.

brightspark

There are ones with titanium coatings, but I'm not sure of the cost, I asked a few months ago and the local supplier didn't even stock them due to the high cost.

Maybe someone here knows more?

MajorMax

brightspark wrote: »

Going to need some clarification.

By fuse, do you mean the MCB or the RCD.

Is it cutting the power to all your sockets, or just some?

Is it cutting the power to the immersion also?

Was you replacement switch wired exactly the same as the old one?

A photo of the 'fuse' and of the switch would help.

1 The fuse in the switch blew
2 it cuts power to all the sockets
3 power to the immersion switch is cut along with all the sockets
4 The switch was different
5 I've no photos

brightspark

MajorMax wrote: »

1 The fuse in the switch blew
2 it cuts power to all the sockets
3 power to the immersion switch is cut along with all the sockets
4 The switch was different
5 I've no photos

1. There isn't usually a fuse in an immersion switch, do you mean it just failed?

2&3. Power to your immersion and sockets going at the same time suggests an RCD tripping, it's possible your immersion has a small earth fault. But it would need to be tested to be sure.

4. Are you sure you wired it correctly? An immersion switch is more complicated than others in your house.

5. It would really help to have a photo of the immersion switch and the 'fuse for the sockets'. As they say a picture is worth a thousand words.

tomdempsey200

To_be_confirmed wrote: »

Our immersion heater had failed recently (when switched on it tripped earth immediately) but this was only about a year and a half since it was last replaced. Are there any immersion heaters that can be expected to last a little longer than that?

yes incaloy..esb online sells them
they're about double the price of regular
I think there's also titanium..more expensive again