Immersion - 'bath' heating issue

slave1

Hi all,

Immersion tripped a few days ago at the circut board.
There is power coming to the timeswitch as it's keeping time and allowing power to the 'sink' element to give some hot water.
No hot water from the 'bath' element so I replaced the stat and still no hot water, just in case the stat was dodgy I got another one yesterday and still no 'bath' hot water.
There is no noise when the 'sink' element is engaged however a slight buzzing when the 'bath' element is selected.
I am neither a plumber nor electrican.
The cylinder is dual coil, around 5ft in height and installed 8-9 years, I've previously replaced both the timeswitch and 'bath' stat.

Any guidance folks??
Thanks in advance

jeepers101

Turn the MCB off and check the switch terminals. Could be a bad connection.

slave1

Will do, I checked the connections at the element when replacing the stat and all were well there, haven't checked at the timeswitch yet

jeepers101

Check the immersion switch. I would imagine the timeclock is fine if it's working on sink.

brightspark

Assuming it was wired correctly the stat controls both 'bath' and 'sink' elements (there are rarely two seperate stats fitted)

If it hasn't worked since the trip, my guess is that the element has failed, alternatively the 'bath' switch is faulty. You really need a meter to check both properly.



Does the top of your immersion look like this

http://www.diynot.com/img/forum/altec_3.jpg

slave1

jeepers101 wrote: »

Check the immersion switch. I would imagine the timeclock is fine if it's working on sink.

As in? Take it off and check the wiring is sound is about all I can do.

slave1

brightspark wrote: »

Assuming it was wired correctly the stat controls both 'bath' and 'sink' elements (there are rarely two seperate stats fitted)
If it hasn't worked since the trip, my guess is that the element has failed, alternatively the 'bath' switch is faulty. You really need a meter to check both properly.
Does the top of your immersion look like this

It's a dual coil cylinder with a stat in the top 'sink' element and another one in the bottom 'bath' element. Both look like your attached photo. Unfortunately I don't have access to a meter. I fear the failed element and my quandary them becomes an electrician or plumber issue, I'd need an electrical to check the electrics 100% but a plumber to change the element (and I can complete the electrics once new element fitted).

brightspark

Perhaps you should ring a plumber and ask if he is able to check the element for you, or find an electrician who is prepared to remove the element. A lot of guys are multiskilled these days (but not all of course)

Bruthal

What exactly tripped, just the Immersion MCB? Is it fed through an RCD? If there is a fault in the element then it should trip the RCD, and depending how close the fault is to the Live end of the element, possibly the MCB also.

If it is fed through an RCD, but only the MCB tripped then it would be probably a direct short from Live to Neutral somewhere before the element itself that caused the trip. This cant really happen inside the element itself, only up as far as the terminal ends of the elements.

It would be a simple task for a sparks to find what the problem is there.

Open circuit in the element, loose connection onto the element, loose connection at the switch bath terminal, or the switch gone faulty, or a connection blown open or the switch damaged from a short which tripped the MCB if it was the MCB that went.

Bruthal

slave1 wrote: »

It's a dual coil cylinder with a stat in the top 'sink' element and another one in the bottom 'bath' element. Both look like your attached photo. Unfortunately I don't have access to a meter. I fear the failed element and my quandary them becomes an electrician or plumber issue, I'd need an electrical to check the electrics 100% but a plumber to change the element (and I can complete the electrics once new element fitted).

If it has 2 seperate stats one could be gone, or the bath element. Simple enough checks for someone that knows what they are at to find the problem anyway. Usually in such cases it is the element that has gone.

Some sparks would change an immersion element too.

slave1

I checked the connections at the bath/sink switch and both elements, all were sound.
The fact the top element is working leads me to believe the timeswitch is okay (I can't see how it could provide power to the 'sink' and not the 'bath'

Here is a photo of the top stat


and here is a photo of the bottom one


So, is it the element then?
If so, I expect it requires the cylinder to be drained in which case I'd go for a plumber, the electrics are a replication of existing wiring which I can manage myself.
Anyone an idea of bottom element cost?
Anyone an idea of plumber charge/length of time required?

Or is there any further check I can carry out?
Thanks again lads

Bruthal

slave1 wrote: »

I checked the connections at the bath/sink switch and both elements, all were sound.
The fact the top element is working leads me to believe the timeswitch is okay (I can't see how it could provide power to the 'sink' and not the 'bath'

Here is a photo of the top stat


and here is a photo of the bottom one


So, is it the element then?
If so, I expect it requires the cylinder to be drained in which case I'd go for a plumber, the electrics are a replication of existing wiring which I can manage myself.
Anyone an idea of bottom element cost?
Anyone an idea of plumber charge/length of time required?

Or is there any further check I can carry out?
Thanks again lads

Well you have the one immersion switch doing both elements i assume?
Assuming the bath half of the switch is ok, as in the switch contacts are closing properly, then its probably either the stat or the element. The bottom(bath) immersion heater has an overheat cutout in it there as well, probably in case it was on with no water in the tank, its the round thing to the right of the stat.

Now here is a test that will tell you if either the stat or the overheat cutout are gone. Get a multimeter if you have one and test between the bottom screw connection of the blue stat, and the element end which is on the right(below the overheat cutout), if it reads 230v or so with the bath immersion on, then either the stat or the overheat cutout is open circuit. If its 0v then they are ok.

If you measure the voltage at at both element ends and its 230v, then its likely the element is gone.

Bruthal

You could also get a phase tester if thats all you have, and test first the bottom terminal of stat, then top, then the left and right terminals of overheat cutout. In all 4 positions the phase tester should light, if it fails to light at the top terminal of the stat then the stat is open circuit. If it fails to light at the right hand terminal of the overheat cutout after lighting on both sides of the stat then the overheat cutout is gone, which is a good possibility. The above tests need to be done with the bath element on, so care is needed.

Not sure if thats a reset button on the overheat cutout thing, have a look at that possibility also. With the power off.

slave1

robbie7730 wrote: »

You could also get a phase tester if thats all you have, and test first the bottom terminal of stat, then top, then the left and right terminals of overheat cutout. In all 4 positions the phase tester should light, if it fails to light at the top terminal of the stat then the stat is open circuit. If it fails to light at the right hand terminal of the overheat cutout after lighting on both sides of the stat then the overheat cutout is gone, which is a good possibility. The above tests need to be done with the bath element on, so care is needed.

Not sure if thats a reset button on the overheat cutout thing, have a look at that possibility also. With the power off.

Checked all of the above and the phase tester bulb was lit at all points.
Forgot to have a look at the 'reset' button. Feck.

But what does this tell me?
Do I know for deffo the problem is the stat (and what are the chances of two new 'dud' stats) or the element.

When I selected the 'bath' there was a definite 'gurgling/gassy' sound

Thanks again for all advice.

For completeness here's the timeswitch (yes, I know I put it in upside down, given the restricted access it was easier)

jeepers101

How long has the immersion been in and do you live in a hard water area?

Bruthal

slave1 wrote: »

Checked all of the above and the phase tester bulb was lit at all points.
Forgot to have a look at the 'reset' button. Feck.

But what does this tell me?
Do I know for deffo the problem is the stat (and what are the chances of two new 'dud' stats) or the element.

If the stat was gone you would have no live indication on points after the stat, (except when the water reaches the set temp). Same for the overheat cutout.

When I selected the 'bath' there was a definite 'gurgling/gassy' sound

If you hear this then all items up to the element are likely ok. If the element was in good shape it should be a clean buzz from the tank when you put an ear against it. The fact its a gassy sound, almost like a fizzling sound suggests the element is gone. On dual immersion elements, the clean buzzing sound is a different tone for bath and sink.


Usually in this state they will trip the RCD if the immersion is on one. Is there one protecting the immersion? Anyway, sounds like the element is gone.

slave1

jeepers101 wrote: »

How long has the immersion been in and do you live in a hard water area?

Cylinder/immersion in place around 8 years, pretty lucky in that I've good water, no scale on kettle (10 years old!!) and no issue with washing machines etc.

slave1

robbie7730 wrote: »

If the stat was gone you would have no live indication on points after the stat, (except when the water reaches the set temp). Same for the overheat cutout.


If you hear this then all items up to the element are likely ok. If the element was in good shape it should be a clean buzz from the tank when you put an ear against it. The fact its a gassy sound, almost like a fizzling sound suggests the element is gone. On dual immersion elements, the clean buzzing sound is a different tone for bath and sink.


Usually in this state they will trip the RCD if the immersion is on one. Is there one protecting the immersion? Anyway, sounds like the element is gone.

Yep, the 'tone' from the element would have been much lower/inaudible previously.
So the stat is grand, and I know how to check in the future too.

Regarding RCD, well I don't want to get lost in electrical detail so all I know is the immersion has it's own trip switch in the main fuse box (which I replaced for the 'old' larger style around 10 years ago).
Thanks again guys

Bruthal

slave1 wrote: »

Yep, the 'tone' from the element would have been much lower/inaudible previously.
So the stat is grand, and I know how to check in the future too.

Regarding RCD, well I don't want to get lost in electrical detail so all I know is the immersion has it's own trip switch in the main fuse box (which I replaced for the 'old' larger style around 10 years ago).
Thanks again guys

Usually we would assume the immersion is on the RCD, and this will trip when there are faults in the element, you would know if the immersion is on the RCD, as the RCD is the trip switch with the test button which will knock off all socket circuits. If you trip the RCD and see is the immersion still on, that will tell us if its on the RCD or not.

It wont change whats wrong with the immersion, it would of just hinted at the problem if the immersion was on the RCD and was tripping it. It must not be on it if the element is indeed gone, but its staying on.

That fizzling sound is usually caused by the element copper jacket splitting, and water is now into the element heating wire itself, sometimes the element wire is open circuited when this happens, and probably tripped the MCB but also blew the short from the element wire to the copper jacket clear, and some current now just flows into the water causing the fizzling sound. This would trip the RCD as soon as any problem starts on the immersion, but with no RCD, the element continues to work for a while and further deteriorate, as can be seen when the elements are removed.

If your immersion is not on the RCD, get if connected through it while changing the element.

slave1

Okay, so pretty much points to replacing the element on the immersion then, I had my electrics weel looked at when I bought the place so I'd say the immersion is on the RCD however will have a look to be sure.
Tks robbie.

So, anyone an idea on plumber charge for element replacement.

jeepers101

Go on, give it a go yourself, there's nothing to it

Bruthal

jeepers101 wrote: »

Go on, give it a go yourself, there's nothing to it

Just what i was thinking earlier, although immersions can vary from being simple to remove, to almost a nightmare.

slave1

Not a f@#king hope:p, gotta keep some money in circulation

Bruthal

that cylinder has a draining tap and all on it by the look of the second photo, so it should be easy to drain at least. Usually changing an element is not too difficult for someone that has done a few. Its the initial loosening of the element is the hard part usually, as they can be well stuck in place.

slave1

Yep, there's a draining tap alright but I have neither a hose long enough to drain nor the wrench to take off the element.
I picked up the element earlier (€22) and plumber quoted €35 for replacing the element tomorrow so given the cost of hose/wrench and chance of internal rain forest (hot press upstairs) I'm going with the plumber route.
Should be interesting to see the state of the old element...

Bruthal

Yea thats not a bad price at all. Elements usually worse when not through an RCD anyway, when it is the element thats gone, often a big split in the element which does not get a chance to get that bad with RCD protected immersions.

Umiq88

Didn't read the whole thread so not sure if its been mentioned but if your confident of wiring yourself but don't have a meter a simple test would be to switch the wiring to each element.

If the bath element works on the sink setting and the sink element doesnt work on the bath setting then you know its the time clock or the switch.

If the bath element doesnt work on the sink setting and the sink element works on the bath setting then you know its the heating element.

You should however get a meter and check voltages to each source. Just to note that when doing any work make sure its isolated at the MCB/RCD feeding it and make sure no one will switch it back on put tape over it or a note.

Bruthal

psittacosis wrote: »

Didn't read the whole thread so not sure if its been mentioned but if your confident of wiring yourself but don't have a meter a simple test would be to switch the wiring to each element.

If the bath element works on the sink setting and the sink element doesnt work on the bath setting then you know its the time clock or the switch.

If the bath element doesnt work on the sink setting and the sink element works on the bath setting then you know its the heating element.

You should however get a meter and check voltages to each source. Just to note that when doing any work make sure its isolated at the MCB/RCD feeding it and make sure no one will switch it back on put tape over it or a note.

Well its the same timeclock and switch feeding both elements, and the tests you mention wont prove its the actual heating element, it could still be the stat, or connections in the immersion unit, or the overheat cutout which the element in question seems to have. Your idea would show the connections are all ok to the flex ends at least though.

But the best tests to do with a meter are tests of the disconnected element itself, a meter can tell if the element is open circuited, or higher impedence than it should be.

An intact 3kw element should read 17 ohms i think, and a 2kw one would be 25 ohms. This is the most simple test to see if the element is the problem. If its gone, it will have an open circuit or a lot higher impedence reading than the intact element, and likely a reading from each end to earth too if the element has split.

slave1

It's done now, I'll take a photo of the removed element when I get home, also got my seeping outside tap fixed when he was draining the tank, €40 in the end

Bruthal

Thats a good price anyway just for changing the element. Just check its on the RCD now and your sorted.

slave1

thar she blows

Bruthal

That looks like its not connected through the RCD, or through one thats not working right. It probably would not get that badly split if it was through one.

jpb1974

Good thread, great info.

I'm pretty sure my immersion element has split also so I'm planning to replace it shortly (well, the old man is going to do it).

Thing is it's only about 3 1/2 years old and very lightly used... but gone already. So it has me slightly concerned.

We're on a private well and I've had the water tested but nothing showed up in terms of overly hard water.

I consulted with my old man who is the electrical and plumbing expert in the family and he says that anything electrical can never be guaranteed to last... an element could last 2 years or it could last 20... you never know.

Anyone have any thoughts as to what would cause such a rapid breakdown in an element like this?

Thanks

M cebee

theres titanium elements available afaik
should last longer

if it's on an rcd you'd know if it's split

jpb1974

She's on an RCD.

About 10 days ago she went from being perfectly quiet to whistling and cackling when in SINK mode.

Turn her on, count to 5 and the noises kick off.

If you switch to BATH she's perfectly quiet again.

Just dug up the water test results from last year and double checked them. No indications of hard water.

jpb1974

theres titanium elements available afaik

Good to know. Have asked the old man to look into it... he's calling out to the plumber wholesalers today.

Bruthal

Sometimes immersion elements are installed so the element is touching the central heating coil in the cylinder, or as in the case of one i removed a month ago, it was twisted into the coil. Had to hammer the element ends through the actual immersion brass baseplate and let them fall into the cylinder to be able to unscrew the thing out, then retrieve the element bits. I was surprised, and maybe lucky at how easy they could be pushed through the endplate.

But overall, the copper jacket becomes very hot even in the water, and they eventually fail, and if limescale is on them the copper jacket becomes even hotter during use.

jpb1974

New titanium element fitted today and all noises are now gone. Happy days!

What was also great was that the old bath element was only about 24 inches long in a 55 inch tall tank... and we never really had enough hot water for a nice deep bath. The new element was much longer so should heat the water a lot better.

Lot of green copper oxide inside the tank and on the old element. Should I been concerned?

M cebee

how much was the titanium heater

jpb1974

€80... the copper equivalent was around €30 but I'd rather pay the few bob extra and put in a more robust solution.