Electric shower fault

mirrormatrix

Quick question on an electric shower as i'm wondering whether to start by contacting shower company or electrician.

I have a Triton T90Z pumped electric shower. Shower is approx 3 years old, but this is an estimate as i only moved into the house last year. Had no issues until about 6 months ago when I had to replace an expired solenoid.

In the last 2 months or so the shower has been tripping the MCB every couple of weeks and i'm now looking at getting this sorted. Trouble is, i'm unsure about whether to get a new shower, or whether I should fault find first in case the shower isn't the problem.

The problem tends to occur during long showers ~15 minutes at the hot setting, though it has happened on showers of shorter duration. I haven't yet run the shower for a long time on cold to see if I can replicate the problem.

Any ideas? I'm inclined to think its the shower rather than MCB or cable, as I had 4 or 5 months running with no issue. Asking here as I don't really want to call someone out to look at the shower, only to have them come again to fit a new one.

foxy farmer

What rating is the MCB? More than likely Mcb tripping due to thermal overload.
At this time of year water going into shower is colder and as a result we turn up temp control to get water to suitable temperature. If shower is running longer trying to heat colder water it is drawing more current for longer. The shower could be running at close to the tripping current of the mcb but its the thermal effect of the current and the length of time the shower is running thats tripping the mcb.
If it trips on colder settings you may have other issues

mirrormatrix

Will check and get back to you. Pretty sure its 40A. Full new consumer unit was fitted last year by RECI electrician. Triton website recommends 40-45A for 9500 kW shower. Would 45A be considered to be better to avoid tripping? Would I be running any other risks by getting an MCB that is greater than the pull on the circuit?

Sleeper12

I'll leave it to the electricians here to tell you what is wrong (I'm putting my money on needing rcbo changed. It's either faulty or under sized) but I can tell you that it's highly unlikely to be the shower. Usually when there is an issue with the shower it'll trip straight away. Intermittent tripping would suggest an electrical issue & not the shower

Bruthal

These showers don't draw more current when the temperature is turned up using the temperature dial, they simply reduce the water flow rate. They put a fixed amount of heat into the water. Lower flow rate = bigger temperature increase.

Is it an rcbo that's tripping, or RCD, rather than an MCB?

It's nearly always RCD based tripping on showers. An MCB tripping would indicate a short. RCD tripping can happen from any slight earth fault, often caused by the elements.

Bruthal

Sleeper12 wrote: »

I'll leave it to the electricians here to tell you what is wrong (I'm putting my money on needing rcbo changed. It's either faulty or under sized) but I can tell you that it's highly unlikely to be the shower. Usually when there is an issue with the shower it'll trip straight away. Intermittent tripping would suggest an electrical issue & not the shower

Could be a problem rcbo alright. Although some might be marginally more sensitive than others, so a new one might prevent tripping, even though existing one might be OK. I'm sure the tolerances are tight though.

John T Carroll

mirrormatrix wrote: »

The problem tends to occur during long showers ~15 minutes at the hot setting, though it has happened on showers of shorter duration. I haven't yet run the shower for a long time on cold to see if I can replicate the problem.

Any ideas? I'm inclined to think its the shower rather than MCB or cable, as I had 4 or 5 months running with no issue. Asking here as I don't really want to call someone out to look at the shower, only to have them come again to fit a new one.

You might check the shower panel itself, make sure that the front cover is securely attached and that there are no cracks on the top, the daughters Mira Sport was doing the same after about 15 minutes and I discovered that one of the (front cover) two top securing set screws was missing (and no where around), the other one was lose, the bottom one was securely attached. The shower had been running away like this for over three years before the tripping started to occur.

mirrormatrix

John T Carroll wrote: »

You might check the shower panel itself, make sure that the front cover is securely attached and that there are no cracks on the top, the daughters Mira Sport was doing the same after about 15 minutes and I discovered that one of the (front cover) two top securing set screws was missing (and no where around), the other one was lose, the bottom one was securely attached. The shower had been running away like this for over three years before the tripping started to occur.

Was only thinking this yesterday. Indeed, one of the two top securing screws is missing. Also, there was previously a hole cut in the top of the case (previous houseowner/spark decided to run cable down in trunking through case top rather than into shower from rear of partition wall), which has now been filled with silicone, but this might also be a bit dodge.

iwillhtfu

I'd guess it's more than likely the heating elements.

OP do you live in a hard water area?

I'd be dubious as to it being the RCBO but you never know. I've seldom seen the rcbo being the issue more often than not it is something in the shower.

Water ingress through those top screw holes will be little to none and unlikely to short out terminals.

Sleeper12

iwillhtfu wrote: »

I'd guess it's more than likely the heating elements.

OP do you live in a hard water area?

I'd be dubious as to it being the RCBO but you never know. I've seldom seen the rcbo being the issue more often than not it is something in the shower.

Water ingress through those top screw holes will be little to none and unlikely to short out terminals.

First port of call on a problem like this is replace the rcbo. This fixes 99% of the time.
Next is check cable for damage all the way to the pull cord & to the shower.
Last would be to replace the pull cord switch.

It can't be the elements. When element fails it will trip instantly & if you change power selector wont trip at all. Limescale on the elements will never make the rcbo trip.
Showers don't cause intermittent tripping. OP I promise you its not the shower. Change RCBO & check wiring for damage

iwillhtfu

Sleeper12 wrote: »

First port of call on a problem like this is replace the rcbo. This fixes 99% of the time.
Next is check cable for damage all the way to the pull cord & to the shower.
Last would be to replace the pull cord switch.

It can't be the elements. When element fails it will trip instantly & if you change power selector wont trip at all. Limescale on the elements will never make the rcbo trip.
Showers don't cause intermittent tripping. OP I promise you its not the shower. Change RCBO & check wiring for damage

Are you an electrician??

iwillhtfu

Sleeper12 wrote: »

It can't be the elements. When element fails it will trip instantly & if you change power selector wont trip at all. Limescale on the elements will never make the rcbo trip.
Showers don't cause intermittent tripping. OP I promise you its not the shower.

so clearly you are aware that there are 2 elements.

Would it be at all possible (seeing as how you clearly know everything) that one element could be faulty and that the shower trips when selecting the second heating element.

There's no need to turn this into a dick swinging comp.

If you have relevant experience fault finding which clearly you don't based on your recommended approach. I'll more than happily bow to this experience but to say something is not possible is just wrong imo.

John T Carroll

mirrormatrix wrote: »

Was only thinking this yesterday. Indeed, one of the two top securing screws is missing. Also, there was previously a hole cut in the top of the case (previous houseowner/spark decided to run cable down in trunking through case top rather than into shower from rear of partition wall), which has now been filled with silicone, but this might also be a bit dodge.

Before I replaced the missing screw etc, I removed the front cover after first isolating the power supply and found that the interior was "dampish" so I dried it out by using a hair dryer and boxed it up, no more tripping for the past 4 years or so.
It doesn't seem very clever to run a cable through the top though!, if you feel confident/competent, you can remove the cover and you could then see some signs of dampness/ingress of water, but ensure the RCBO is switched out (down) first. It may not be your problem but its a very cheap first step at any rate.

iwillhtfu

John T Carroll wrote: »

It doesn't seem very clever to run a cable through the top though!,

IIRC these showers allow cable entry through the top and bottom I think the cable is routed through an internal housing which doesn't allow water into the actual shower housing.

In saying that I wouldn't consider it best practice especially if there was a stud wall to go through.

Sleeper12

iwillhtfu wrote:

If you have relevant experience fault finding which clearly you don't based on your recommended approach. I'll more than happily bow to this experience but to say something is not possible is just wrong imo.

I am the only person on boards.ie that has been triton & Aqualisa trained to repair showers. I am an electric shower engineer. It is what I do for a living I work on close to 1000 showers per year.

This problem op has is intermittent tripping. It's not tripping as he changes from one to two elements. As I said earlier this would confirm that an element is at fault.
The shower doesn't change the way it behaves during the 10 minute shower. If it works for 1 minute it will work for 20 minutes.
An over sensitive rcbo (&I'd rather over than under) will will trip after a few minutes.
Intermittent tripping is not the fault of the shower. It is most likely rcbo but could be damaged cable. Limescale can NOT damage an element in such a way to cause the rcbo to trip. Heavy limescale CAN cause the Tco to trip but this only effects the water temperature. It also resets itself.
I have jet to give out incorrect advice here
OP please, please post here when you get your rcbo replaced.

iwillhtfu

Sleeper12 wrote: »

OP please, please post here when you get your rcbo replaced.

Or when you find the actual fault

Sleeper12

iwillhtfu wrote:

Or when you find the actual fault

John T Carroll

[QUOTE=iwillhtfu;
In saying that I wouldn't consider it best practice especially if there was a stud wall to go through.[/QUOTE]

The top cable entry is directly above the Terminal Block (obviously) and doesn't show any special glanding/sealing arrangement, see Fig.8 of the link. One way or the other the entry would have to be sealed very well to avoid any water ingress.
http://www.tritonshowers.ie/media/1201627/t90z_fitting_book.pdf

iwillhtfu

The terminals are mounted on a raised plastic part the cables actually run behind then loop back up it's not very clear in that photo in fairness. The only exposed part is where the pipes come in which is below the terminals

Bruthal

iwillhtfu wrote: »

I'd guess it's more than likely the heating elements.

OP do you live in a hard water area?

I'd be dubious as to it being the RCBO but you never know. I've seldom seen the rcbo being the issue more often than not it is something in the shower.

Water ingress through those top screw holes will be little to none and unlikely to short out terminals.

Yea its usually the elements causing rcd,/rcbo trips

Bruthal

Sleeper12 wrote: »

First port of call on a problem like this is replace the rcbo. This fixes 99% of the time.
Next is check cable for damage all the way to the pull cord & to the shower.
Last would be to replace the pull cord switch.

It can't be the elements. When element fails it will trip instantly & if you change power selector wont trip at all. Limescale on the elements will never make the rcbo trip.
Showers don't cause intermittent tripping. OP I promise you its not the shower. Change RCBO & check wiring for damage

Rcbo replacement fixes 99 percent of all shower rcbo trips?

Almost no chance it's cable. Pulling that out to inspect is over the top.

Shower elements can have ingress of water. This can cause leakage current on the trip threshold. The nearer to the neutral end of element the dampness is, the less leakage current occurs. So it can cause infrequent trips.

The chance of the pullchord causing it would seem almost impossible. Dismissing the shower, a high power water based heater, in favour of the pullchord and cable is unusual.

It could be the rcbo. With infrequent trips I'd consider it a possibility. But I wouldn't just completely dismiss the shower. Cables and rcbos can be tested easily.

John T Carroll

Bruthal wrote: »

Rcbo replacement fixes 99 percent of all shower rcbo trips?

Almost no chance it's cable. Pulling that out to inspect is over the top.

Shower elements can have ingress of water. This can cause leakage current on the trip threshold. The nearer to the neutral end of element the dampness is, the less leakage current occurs. So it can cause infrequent trips.

The chance of the pullchord causing it would seem almost impossible. Dismissing the shower, a high power water based heater, in favour of the pullchord and cable is unusual.

It could be the rcbo. With infrequent trips I'd consider it a possibility. But I wouldn't just completely dismiss the shower. Cables and rcbos can be tested easily.

I was thinking more of dampness at the terminal block causing a leakage current, live to earth or even neutral to earth, it surely wont do any harm to have a look into the shower internals.

meercat

Sleeper12 wrote: »

First port of call on a problem like this is replace the rcbo. This fixes 99% of the time.

Would agree here
Would however check the load and shower first. Have replaced numerous rcbos (garo mostly)

Bruthal

John T Carroll wrote: »

I was thinking more of dampness at the terminal block causing a leakage current, live to earth or even neutral to earth, it surely wont do any harm to have a look into the shower internals.

Interestingly, water between N and E wont really trip an RCD.

L to E can alright. Probably unlikely here though.

Might be worth a look into the shower.

Sleeper12

Bruthal wrote: »

Rcbo replacement fixes 99 percent of all shower rcbo trips?

Almost no chance it's cable. Pulling that out to inspect is over the top.



The chance of the pullchord causing it would seem almost impossible. Dismissing the shower, a high power water based heater, in favour of the pullchord and cable is unusual.

It could be the rcbo. With infrequent trips I'd consider it a possibility. But I wouldn't just completely dismiss the shower. Cables and rcbos can be tested easily.

Robbie I'm being misquoted there. Rcbo replacement fixes 99 percent of all shower rcbo trips? We are talking about intermittent tripping here so yes replacing the RCBO sorts 99 percent of these issues. As I said earlier the RCBO tripping instantly is a different story & would indicate a blown element or not so often but possibly a fault in the pump.

Remember OP never mentioned smell of burning. Never mentioned strange noise. Never mentioned fluctuations in power, pressure of temperature.

"Shower elements can have ingress of water. This can cause leakage current on the trip threshold. The nearer to the neutral end of element the dampness is, the less leakage current occurs. So it can cause infrequent trips."
This just isn't the case. While water can cause it to trip If you reset the RCBO & tried the shower it would trip instantly so this isnt intermittent tripping as described by the OP.

Once you've ruled out that is not the shower You must look at the RCBO? Them You MUST inspect the cable. If its not the shower & not the RCBO you really think checking the cable is over the top??

We get approx 40 calls like this per year. I don't go on any of these. I call my REC who doesn't repair showers & ask him to replace the RCBO. 40 Times a year & only twice was it not the RCBO. Twice it was the damaged cable. Never ever has the shower caused intermittent tripping. So you have to start in the most likely place. The RCBO.

To the ones suggesting replacing the shower I say shame on you. Its like cutting off your whole leg because you have an ingrown toenail.
OP get a REC & ask him to replace the RCBO. It'll cost around 100 euro or slightly over. Replace the element as someone suggested around 150 euro plus the cost of REC to call out & replace the RCBO anyway.


I'll leave it there. I do hope OP reports back & in answer to your question that everyone hasn't answered: Call out an REC not a shower repair company. I own a shower repair company & thats my honest advise

Bruthal

Sleeper12 wrote: »

Robbie I'm being misquoted there. Rcbo replacement fixes 99 percent of all shower rcbo trips? We are talking about intermittent tripping here so yes replacing the RCBO sorts 99 percent of these issues. As I said earlier the RCBO tripping instantly is a different story & would indicate a blown element or not so often but possibly a fault in the pump.

Remember OP never mentioned smell of burning. Never mentioned strange noise. Never mentioned fluctuations in power, pressure of temperature.

Intermittent trips of RCDs usually dont involve any burning. If water inside the shower was causing trips of RCD, between trips, all would work as normal

This just isn't the case. While water can cause it to trip If you reset the RCBO & tried the shower it would trip instantly so this isnt intermittent tripping as described by the OP.

Water causes a wide varying amount of residual current. We cant really say it will always be above 30ma, when it is in a device that heats up regularly.

Once you've ruled out that is not the shower

You did that saying it cant be.

You must look at the RCBO? Them You MUST inspect the cable. If its not the shower & not the RCBO you really think checking the cable is over the top??

It is when it must involve pulling it out of the installation, not very realistic.....

Next is check cable for damage all the way to the pull cord & to the shower.

The cable can be tested without having to visually inspect along every inch of it.

We get approx 40 calls like this per year. I don't go on any of these. I call my REC who doesn't repair showers & ask him to replace the RCBO. 40 Times a year & only twice was it not the RCBO. Twice it was the damaged cable.

Id be genuinely interested to know what damage the cable had, that caused intermittent tripping. Carbonized from severe burning perhaps....

Never ever has the shower caused intermittent tripping. So you have to start in the most likely place. The RCBO.

I have already said it might be the RCBO, its not as if Im disagreeing. I disagree that its not possible for a shower to intermittently trip an RCD.

To the ones suggesting replacing the shower I say shame on you.

I wouldnt say shame on them. But its not a good course of action.
Having said that, no one suggested replacing the shower.

I'll leave it there. I do hope OP reports back & in answer to your question that everyone hasn't answered: Call out an REC not a shower repair company. I own a shower repair company & thats my honest advise

Remember, im not remotely saying its not the RCBO. It probably is. Where id differ is, in saying intermittent trips cant be a problem in the shower.

Very infrequent trips are probably the RCBO, but to say an appliance will always cause instant tripping, i wouldnt agree with.

Sleeper12

Bruthal wrote:

Id be genuinely interested to know what damage the cable had, that caused intermittent tripping. Carbonized from severe burning perhaps....

One was damaged cable in the attic. I honestly can't remember what the damage was.
The other one I do remember I wasn't there but it was described to me: whoever fitted the shower used a Stanley knife or something like that to strip the wires. They put a small slice in the neutral wire without knowing about it. The earth didn't have a sleeve. The earth wasn't quite touching the neutral but they weren't quite not touching. Every few weeks it would trip. I assume with the vibration every now and then the earth moved a tiny fraction and it tripped
I hope I explained that in a way that makes sense.:)

mirrormatrix

Ok, sorry for the delay. I'm back with some potential answers and a few clarifications.

A lot of this is new to me, but comments here are definitely helping me to look for potential solutions. I've checked the shower first, and it's not 9.5 kW but 8.5 kW. I had googled initially not realising that the T90Z has an 8.5 and 9.5 kW model. The RCBO (I now know what that is!) is 32A.

By my calculations, a 8500W shower at 230V has a current of 36.9A. So it seems obvious to replace this the 32A RCBO with a 40A. Triton's website also recommends a 40A RCBO for the 8.5kW shower. I haven't checked the cable, and the inside of the shower seemed dry when I had a look inside the case, so i'm planning on getting someone to replace the RCBO on the basis that it probably should be 40A regardless of whether any other problems exist. I'll report back once I figure out if this solves the problem.

Thanks again for all the help and suggestions

Bruthal

Yea the 32 amp is a fraction small. They can run the 8.5kw shower for a fair while without tripping. But it should be a 40 amp one.

Sleeper12

Sleeper12 wrote:

I'll leave it to the electricians here to tell you what is wrong (I'm putting my money on needing rcbo changed. It's either faulty or under sized) but I can tell you that it's highly unlikely to be the shower. Usually when there is an issue with the shower it'll trip straight away. Intermittent tripping would suggest an electrical issue & not the shower

My very first comment.

Sleeper12

mirrormatrix wrote:

Will check and get back to you. Pretty sure its 40A. Full new consumer unit was fitted last year by RECI electrician. Triton website recommends 40-45A for 9500 kW shower. Would 45A be considered to be better to avoid tripping? Would I be running any other risks by getting an MCB that is greater than the pull on the circuit?

Question for the electricians on the page. If full consumer board was fitted by reci electrician last year and he installed a 32amp should he come back and fit correct one for free?
Can't OP contact RECI itself if he can't get him back?