Is replacing Immersion Heater element necessary if central heating always done by oil?

Bita_dis_bita_dat

Our immersion heater has corrosion around the heating element at top of the boiler (not the wiring itself but around and over the base plate where the reset button is on the element top). It trips the fuse box as a result - started 2 nights ago and I've left it tripped off since. I'm about to order the heating element to replace it altogether as to solve the corrosion is too big a task if not impossible and I don't want it spreading further through the system.

I have a query as to the fact we never use electric immersion to heat our water/radiators. We always use oil and the boiler for central heating and water, but because this burnt-out element trips the fuse box controlling the heating controllers for the oil burner can't turn on either. Is it necessary to replace/wire up the immersion if heating is always done with oil? Do the immersion controls also control valves or the pump that's responsible for central heating? As a temp fix or to get heat on while waiting for part replacement can I unwire the immersion element so it won't trip the fuse but leave it locked and sealed in place and still use oil burner for heat & water?

Thanks.

Bita_dis_bita_dat

*not corrosion but rather rust at the moment

mickdw

If you don't use the immersion, you can disconnect the wiring from the tank and leave the unit on/ in the tank as is.

mickdw

Just to add, the immersion is only for hot water. It doesn't heat rads.

Bita_dis_bita_dat

https://www.boards.ie/discussion/comment/118444358#Comment_118444358

Thanks for the reply, I was hoping it was possible. So literally disconnect wiring, secure it as to not shock someone/something, flip the fuse switch back on and use the central heating as normal?

mickdw

I'd disconnect the supply cable at the switch if this is going to be a semi permanent setup.

Buffman

That still looks wet in the photo so you probably still have a small leak. To fix the leak you'll have to replace it or blank it if you don't want an immersion element.

As a temporary fix to get the oil going again I'd disconnect the element at the immersion switch on the element side and refit the switch so you don't have any live wires exposed.

10-10-20

Yes, definitely isolate this at the switch, but please don't go isolating devices such as this unless you know how to safely do so.

Also, by isolating this you aren't addressing the leak and that will either worsen over time. Finally, should your oil heating fail, you will then have no backup for heating the water. I'd suggest getting the immersion repaired instead.

Bita_dis_bita_dat

https://www.boards.ie/discussion/comment/118444503#Comment_118444503

Disconnected the immersion at the switch with no problem. Unfortunately, the same issue is happening - the central heating runs for a few mins but the fuse trips again still. The plot thickens...

jimf

most likely a water leak at the circulating pump valves at your boiler

first place always to look

John.G

https://www.boards.ie/discussion/comment/118444863#Comment_118444863

If its the RCD (earth leakage) is tripping then ensure the live, the neutral and the earth are all disconnected at the switch and see if RCD still trips.

elgicko

Immersion completely different to radiator heating . All Immersion does is heat up water in tank, it does not interact with heating at all. View an immersion like a heating element in a kettle.

The radiators are heated through a circuit, flow and return, look on this like a circuit. Part of the circuit is a coil of pipe going through the hot water tank, the water does not mix with the tank water As the water circulates the water in the tank gets hot as the water in the heating circuit heats it, similar to dropping a hot stone into cold water.

elgicko

Regarding your problem, there is a disparancey of voltage going through your RCD. Are you losing all power (except lights), if so, the RCD is doing its job and trips out because it detects the erratic voltage.

There sounds to be a big problem with your immersion, replace it and see if the problem is resolved. Make sure the existing one is earthed. Be careful.

Solid advice by John G. If it was me I would disconnect immersion at fuse box. If that solves you problem, you know it is the immersion.

If you don't know what your doing leave it to the pro's

Bita_dis_bita_dat

https://www.boards.ie/discussion/comment/118446815#Comment_118446815

Just to clarify; it is just the circuit breaker that our central heating is connected to that is tripping. All other breakers in the fuse box are fine. I figured it was the immersion tripping it initially as moisture appeared around the wiring (only arrived and as I figure it could have happened from a slightly damp bed sheet that was thrown over the boiler to dry). However, having removed the immersion from the equation by disconnecting it entirely from it's circuit and then also turning off that circuit breaker but the central heating circuit is still tripping off after being on for 10-20 mins.

Next, I was gonna try switching the fuse in the circuit breaker and test and see does it stay on, maybe it's just the MCB 🤷‍♂️ It's odd that it stays on for approx 15mins before tripping - nothing on the circuit that I can see that's tripping it after that time, tested it with the pump on or off and its the same, and nothing switched on in the house bar the fridge when testing also. See my other post trying to identify my MCB if you have any insight in the matter - https://www.boards.ie/discussion/2058227277/what-is-this-style-of-mcb-called-see-attached-image/p1?new=1

jimf

any mice chewing wires

John.G

Just to be clear, you a say a circuit breaker or MCB is tripping, if so, this will only trip under overload conditions, can you clearly identify the one in question in case its a combined overload and earth leakage circuit breaker known as a RCBO in which case it can be either a overload condition or a earth leakage problem.

maestroamado

I am guessing the problem internal in the element... i do not see anything wrong with the wiring and of course its always dry... taking a wire off at the switch prob best option...

mickdw

He has disconnected the immersion entirely now and still has a problem.

mickdw

The immersion is a red herring.

Do you have an outdoor burner?

John.G

We are (or at least I am) going around in circles until we know the type of circuit breaker is, post #14 might suggest a RCD/RCBO but just don't know, also "having removed the immersion from the equation by disconnecting it entirely from it's circuit and then also turning off that circuit breaker but the central heating circuit is still tripping off after being on for 10-20 mins."

Just to repeat that disconnecting the immersion entirely means disconnecting the Live, the Neutral and the Earth wires.

jimf

if your boiler is wired as it should be it should be protected by a 5amp supply

it will be very sensitive so easily tripped

it could be caused by a faulty boiler stat as well as a mouse chewing wires that flex slightly when hot

it is obvious your burner is the cause get somebody to check it over

elgicko

If you have disconnected the immersion from the fuse box, the MCB - disconnect live/neutral/earth. If the problem persists the issue is not the immersion.

What is tripping after above completed? Is it the heating (boiler) MCB or RCD?

How old is boiler? is it gas or oil? Could be an internal issue with the boiler!

You are getting close to calling an expert if the problem.is the boiler, could be a lot of.different things.

Bita_dis_bita_dat

MCB is tripping.

Trips when the boiler isn't running. Yesterday it would run for approx 20 mins then trip again with nothing else running in the house. Today I disconnected the wires from the MCB and reconnected them again (was gonna switch out the fuse.) and it ran for over an hour with the boiler on, so we got the house heated. The MCB tripped again then.

Don't know the exact age of the boiler, could be due to being replaced. Runs on Oil.

It's close to that alright, was just trying to identify the issue really - thought it was the immersion first so was came here for thoughts.

Wearb

AFAIK Only a qualified electrician is allowed to take the cover off the consumer unit (fuse box). Not to mention removing wires from within.

maestroamado

https://www.boards.ie/discussion/comment/118457899#Comment_118457899

in your own home you do as you please... thankfully...

maestroamado

https://www.boards.ie/discussion/comment/118457182#Comment_118457182

if the live is disconnected the circut is broken...

elgicko

You are getting different problems, there is no consistency. Could be anything

Switch out the MCB for the heating (not immersion), make sure you turn off the consumer unit at the main fuse and be careful not to go near the main lives going into he 63amp fuse. if that doesn't work, call a sparks to diagnose

Valiant effort!!

Wearb

https://www.boards.ie/discussion/comment/118457958#Comment_118457958

That is certainly not the case. So be careful of the advice that you give.

maestroamado

https://www.boards.ie/discussion/comment/118458006#Comment_118458006

Give an example of what you say... i am not giving advise but you are...for me people can do as they please in their owned private property...

Wearb

https://www.boards.ie/discussion/comment/118458033#Comment_118458033

That information is widely available and known amongst the trades. There is lot of electrical work that's not allowed in your own home unless you have the proper qualifications. If you do not believe me, then ask over in the electrical forum. The same goes for working with gas.

MOD NOTE:I have tried to keep this thread from having posters suggest dangerous (and illegal) practices, without being heavy handed. From here on I will infract any any such suggestions. Don't reply to this as it will only take the thread further off topic.

Andrea B.

https://www.boards.ie/discussion/2058226865/is-replacing-immersion-heater-element-necessary-if-central-heating-always-done-by-oil

Full circle.

If you have a switch at immersion with on/off _sink bath:

Switching to off, isolates live and neutral of element from circuit.

Assuming switch fuctioning, when off, if your rcd/rcbo/mcb still continues to trip, you have an electrical fault elsewhere.

Bita_dis_bita_dat

Folks, thanks for all the replies and effort to solve this!

I'm fairly confident immersion is not the issue and indeed was a red herring as someone suggested XD. Its completely removed from the equation now.

https://www.boards.ie/discussion/comment/118458094#Comment_118458094

If I'm understanding you correctly this is the next step I'm attempting but stuck on. I want to switch the MCB with an MCB that appears to be working fine (has never tripped). The problem I'm facing having taken off the fuse board case is that it's wired in an old-school fashion I presume - different from my understanding of modern fuses boards. You can check it out in my other post here - https://www.boards.ie/discussion/2058227277/what-is-this-style-of-mcb-called-see-attached-image#latest .

All the MCBs are sitting on a copper(?) bar with prongs that they're all wired to. Seems to take one MCB off I either have to bend that bar down so the prong is removed from under the MCB or remove bar from the board itself, OR there's a sound method of removing an MCB from this setup where you can lift it up off the prongs. Either way, I'm having a problem searching a solution online.

Wearb

https://www.boards.ie/discussion/comment/118468523#Comment_118468523

You need a registered electrician.

Irish Steve

You're not going to like my reply, the simple answer to your issue is that if you don't know enough about a switch panel that's about 30 years old, you shouldn't be in there, and that's without the specific legal implications of modern regulations that are a lot more restrictive than they used to be, in order to protect people from dangerous changes done by "mates" to help out.

In situations like this, the internet is NOT your friend, as there are way too many supposed guides on how to do things that are fundamentally dangerous, because they are not specific to a manufacturer, or system, and using a guide for another make or system can result in a dangerous result, the copper bar you mention is indeed a distributor, and in the wrong circumstances, it can be live when you don't expect it to be, so if you are not 100% sure of what you're working with, then the ONLY safe route is an electrician that's approved to do the work you need done.

I'm not a registered electrician, but I know more than enough about what's involved, because i had to do similar, and more complex, back when the regulations didn't exist, and I wired my own house in the UK back in the 70's, among other things, and in those times, there was no self certification, it had to be signed off by the electricity supply company before it could be connected, and there was no flexibility with them.

Please, for your own safety, get some professional help in to resolve this, it's not a run of the mill fault, so it needs to be accurately diagnosed with specialised test equipment that will be able to isolate the faulty item or wire, and make sure that the repair is good.

dathi

https://www.boards.ie/discussion/comment/118458167#Comment_118458167

https://safeelectric.ie/help-advice/controlled-restricted-electrical-works/

have a read here

corner of hells

I'm a retired electrician, OP you need an experienced registered electrician .

greasepalm

Curious how you got hot water in the summer as oil boilers were very hot in heating the rads.

maestroamado

https://www.boards.ie/discussion/comment/118472217#Comment_118472217

That is just advise and best practice not regulation... there are strict regulation enforced for now builds and so there should be... tjhere is no regulation for this... just a competent person... i am a qualified electrician but did career change...

Wearb

https://www.boards.ie/discussion/comment/118472474#Comment_118472474

MOD NOTE: YOU NEED TO DROP THIS INSISTENCE THAT DOING ALL THE ABOVE WORK IS LEGAL IN YOUR OWN HOME.

IF YOU PERSIST, I'LL TAKE MORE SEVERE ACTION AGAINST YOU.

dathi

https://www.boards.ie/discussion/comment/118472474#Comment_118472474

a statutory instrument is the legislation that sets out the law, if you had bothered to google Statutory Instruments, S.I. No. 264 of 2013, that was mentioned in the article you would have seen that restrictive electrical works is against the law

Wearb

This thread has now run its course and had things clarified.

OP, if you want it reopened, just drop me a PM