Triton T90z problem

Keith186

I'm not sure if this should be in the plumbing or electrical forum.

I'm having an issue with this shower (only about a year old I'd guess but it was done by previous owner). It's fed from the cold water tank in the attic. The tank ran dry on Sunday when I was in the shower. Pump was running very fast for about 5 seconds due to low water supply.
I fixed the attic tank problem (blocked inlet valve in ballcock stopped all water going in) yesterday. Attic tank back to normal now. Went to use shower this morning and it seemed like it could not get the water in quick enough as the pump was going very fast. I held the shower head down very low to get the flow rate/pressure up and this worked. Water was now getting pumped properly and the shower was making its normal noise and water was at the right temperature.

However after a minute or two the shower switched off. The red light on the pull cord switch went off. Turned it off and on again and started the shower but the same thing happened again after a minute.
There is no separate MCB for the shower and nothing tripped in the fuse board.

Anyone know where to start with this?

I'm hoping it got a bit hot when it could not get the water in initially and that it cut out due to this and that it will magically be fine when I get back later.

If not any ideas where to start?
There would have been a small amount of dirt gone into it from the attic tank so I was thinking of cleaning the internal filter. Would this problem still cause it to turn off at the pull cord switch though or should I be looking at burnt out bushes or something along those lines?

Thanks

John T Carroll

There are lots of posts re the pull cord switch, if you do a boards.ie search under "Shower Pull Cord Switch" you will get alot of useful info.

Keith186

Done some more troubleshooting there.
There is an MCB it just wasn't labelled. It has never tripped.
Shower does not turn off when top dial for power is set to cold or economy.
As soon as it's on the high power setting and you turn the temperature dial up near half way it cuts out then.

I opened the pull cord switch and it's in near new condition, no signs of melting.

Sleeper12

Keith186 wrote:

Done some more troubleshooting there. There is an MCB it just wasn't labelled. It has never tripped. Shower does not turn off when top dial for power is set to cold or economy. As soon as it's on the high power setting and you turn the temperature dial up near half way it cuts out then.

You most likely blew one of the elements by running the shower with the elements on with no water running . Picture boiling the kettle with no water in it.
New element is around 150 Euro supplied and fitted

Keith186

I turned off water fairly quickly as I copped what was happening straight away. I was worried something like that might have happened.

Opened her up there and bled a tiny bit of air out of it. Must've been causing the problems as it worked grand at high temperature for the few minutes I tested it. Should be OK now!

John T Carroll

Keith186 wrote: »

I turned off water fairly quickly as I copped what was happening straight away. I was worried something like that might have happened.

Opened her up there and bled a tiny bit of air out of it. Must've been causing the problems as it worked grand at high temperature for the few minutes I tested it. Should be OK now!

A few interesting points there, you say in your first post that the MCB was tripping, I wonder why, you possibly have a RCBO (with test button) and maybe, for some reason, it was tripping on earth leakage. As far as I know the heating elements should be protected by a low water pressure cut out which should open the micro switches supplying power to the heating elements on low/no water pressure.

Keith186

John T Carroll wrote: »

A few interesting points there, you say in your first post that the MCB was tripping, I wonder why, you possibly have a RCBO (with test button) and maybe, for some reason, it was tripping on earth leakage. As far as I know the heating elements should be protected by a low water pressure cut out which should open the micro switches supplying power to the heating elements on low/no water pressure.

Hi John, MCB did not trip at the board at all, only the pull cord switch did. There is an RCBO on the fuse board (also didn't trip).

Took a shower and it cut out after a while so it's not fixed.

Never had any problems with it before until the water ran real low a couple days ago so maybe it is the element that's burnt out as Sleeper said.

There was a small bit of soot on the inside of the cover near the bushes, is that normal?

John T Carroll

Keith186 wrote: »

Hi John, MCB did not trip at the board at all, only the pull cord switch did. There is an RCBO on the fuse board (also didn't trip).

Took a shower and it cut out after a while so it's not fixed.

Never had any problems with it before until the water ran real low a couple days ago so maybe it is the element that's burnt out as Sleeper said.

There was a small bit of soot on the inside of the cover near the bushes, is that normal?

Will it still run continuously on economy setting? if it isnt, and if the pump is just cutting out (stopping?) then you possibly/probably have a pump problem.
If it will run continuously on economy setting but not on full power then its possibly the second element which can be isolated and tested by someone competent to do so.
I have only seen the cover off one 90Z and there was a good bit of sooting but that was two years ago and the shower is still running away fine, now around 7 years old, I think.

nmacc

I'll preface this by saying that I can't remember if this issue applied to the T90Z, but there can be a problem with the solenoid that controls the water flow in some models.

The solenoid is energised to allow water flow. There is a self-resetting thermal fuse within the windings and these can misbehave. If this happens then the shower will shut off after a few minutes of operation. It's a heat-related issue, so the cooler the shower is operating, the longer it will run before cutting out. The fix is to change the solenoid coil.

However I'm concerned with the description of the pull switch. If the neon goes out and the shower cuts out simultaneously, then there is a problem with the switch or the MCB and that needs to be thoroughly inspected. If there is a bad connection in the switch it will get hot - VERY hot, and if it's in the bathroom ceiling, you have the possibility of a fire in the loft. Not ideal.

Sleeper12

This statement is very confusing.

Remembering that the solenoid valve is always situated on the cold side of the heating can & the solenoid coil is nowhere near the water at all, so the temperature of the water has absolutely no effect on the solenoid.
A faulty solenoid coil can be totally dead or it can work for a minute or two & cause itself to overheat & shut off. The coil will behave like this if you are running stone cold water or scalding hot water. It makes no difference.
I can usually diagnosis a shower fault over the phone or even here on boards but op is not being very clear in his description & it seems to be different each time he posts.
The soot described is carbon deposit. It's perfectly normal to have this.

It now looks like there is actually nothing wrong with the shower and the rcbo needs replacing.

Keith186

The shower runs continuously until temperature is turned up enough, it will cut out on both economy and full power then.

To clarify the MCB/RCBO never tripped. The pull cord light went out and when you turn it off and on it works again. I would have expected the MCB to trip instead of this happening but I'm not an electrician.

I checked inside the pull cord switch and it doesn't look like it's overheating or anything of the sort, not compared to ones I've seen before that were scorched black.

Could the low pressure have affected the RCBO somehow? I didn't think it could. Shower always worked perfectly hundreds of times until this incident.

John T Carroll

Keith186 wrote: »

The shower runs continuously until temperature is turned up enough, it will cut out on both economy and full power then.

To clarify the MCB/RCBO never tripped. The pull cord light went out and when you turn it off and on it works again. I would have expected the MCB to trip instead of this happening but I'm not an electrician.

I checked inside the pull cord switch and it doesn't look like it's overheating or anything of the sort, not compared to ones I've seen before that were scorched black.

Could the low pressure have affected the RCBO somehow? I didn't think it could. Shower always worked perfectly hundreds of times until this incident.

Now, when you say it cuts out, are you saying that the pull cord light goes out? and you then have to "reset" it by pulling it Off then On again?.

Re turning up the temperature control knob, all you are doing there is decreasing the water flow which will increase the water temperature as you are passing less water through a fixed heating output. The decreased flowrate may be having some effect on the pump power but this should be tiny, the pump motor probably only draws around 100 watts (0.1 Kw) anyway which is nothing in comparison to the power pulled by the heating elements of around 8500 watts (8.5 Kw)

If the RCBO isnt tripping then I cant see how this is the problem.

If the pull cord switch is acting up why not renew it anyway with one rated at say 50 Amps.

If you havnt already done so you might also clean the pump inlet filter.

Keith186

John T Carroll wrote: »

Now, when you say it cuts out, are you saying that the pull cord light goes out? and you then have to "reset" it by pulling it Off then On again?.

....

If the RCBO isnt tripping then I cant see how this is the problem.

If the pull cord switch is acting up why not renew it anyway with one rated at say 50 Amps.

If you havnt already done so you might also clean the pump inlet filter.

Yes to the first part, that's exactly what happens.

Is there any reason why the switch could be acting up now all of a sudden?

I'll try clean the filter later, hopefully there is an isolated valve on the feed from the attic.

John T Carroll

Keith186 wrote: »

Yes to the first part, that's exactly what happens.

Is there any reason why the switch could be acting up now all of a sudden?

I'll try clean the filter later, hopefully there is an isolated valve on the feed from the attic.

OK then, if you are confident that you can safely use a multimeter, then I would repeat the exercise, and after the red light goes out, I would check for 230V, L/N on the incoming side of the pull cord switch and ditto at the shower side of the pull cord switch, (do not switch it to off before you carry out the test) then you can determine if its the pull cord switch or perhaps a faulty RCBO as Sleeper12 has suggested.

Sleeper12

John T Carroll wrote:

If the RCBO isnt tripping then I cant see how this is the problem.

A faulty rcbo can cause the exact issue described here. A faulty rcbo doesn't have to trip, in fact some faulty rcbo can't trip because they are faulty.
As I said earlier op isn't describing the issue very well but from what he has said so far it sounds like a healthy shower & the issue is with the pull cord switch or rcbo.

Keith186

I'll try and check it later thanks lads.

Wearb

Sleeper12 wrote: »

A faulty rcbo can cause the exact issue described here. A faulty rcbo doesn't have to trip, in fact some faulty rcbo can't trip because they are faulty.
As I said earlier op isn't describing the issue very well but from what he has said so far it sounds like a healthy shower & the issue is with the pull cord switch or rcbo.

The test described by JTC will go a long way to identifying where the problem lies.

OP. It needs to be done with great care by someone with experience. 240 volts through that supply is no place to be learning.

Keith186

John T Carroll wrote: »

OK then, if you are confident that you can safely use a multimeter, then I would repeat the exercise, and after the red light goes out, I would check for 230V, L/N on the incoming side of the pull cord switch and ditto at the shower side of the pull cord switch, (do not switch it to off before you carry out the test) then you can determine if its the pull cord switch or perhaps a faulty RCBO as Sleeper12 has suggested.

Done the test there and I'm getting 230ish on the incoming side and when the light goes off I'm getting zero on the shower side.

I tipped the pull cord switch with the leads when it was dangling and the slight movement caused the shower to come back on. So I guess that means time for a new switch?

I always use the switch before and after shower but the constant use probably broke something inside it perhaps?

Still seems too coincidental that the switch would start acting up as soon as I had the lower pressure issue.

John T Carroll

Keith186 wrote: »

Done the test there and I'm getting 230ish on the incoming side and when the light goes off I'm getting zero on the shower side.

I tipped the pull cord switch with the leads when it was dangling and the slight movement caused the shower to come back on. So I guess that means time for a new switch?

I always use the switch before and after shower but the constant use probably broke something inside it perhaps?

Still seems too coincidental that the switch would start acting up as soon as I had the lower pressure issue.

I would isolate the power by pressing the test button on the RCBO and making sure that the (RCBO) switch is down, check with your multimeter that you have no voltage at the pull cord switch and then use a insulated screwdriver to check that all the terminal screws are tight, if they are then it looks very much as if a new pull cord switch is required. If you want to be extra careful you might like to trip the main isolater to kill the incoming power as well as tripping the RCBO but that means having a good torch/light to hand to see what you are doing, in any event be careful.

Keith186

John T Carroll wrote: »

I would isolate the power by pressing the test button on the RCBO and making sure that the (RCBO) switch is down, check with your multimeter that you have no voltage at the pull cord switch and then use a insulated screwdriver to check that all the terminal screws are tight, if they are then it looks very much as if a new pull cord switch is required. If you want to be extra careful you might like to trip the main isolater to kill the incoming power as well as tripping the RCBO but that means having a good torch/light to hand to see what you are doing, in any event be careful.

Cheers John I'll check that they're tight, I'd say they are but I'll double check. Will probably be Saturday. If I need to get a new switch I'll get one up to 50A like you said. The MCB is 32A which I presume will be fine with that switch as they work independently?

John T Carroll

Keith186 wrote: »

Cheers John I'll check that they're tight, I'd say they are but I'll double check. Will probably be Saturday. If I need to get a new switch I'll get one up to 50A like you said. The MCB is 32A which I presume will be fine with that switch as they work independently?

There are numerous posts here re RCBO ratings for Electric Showers, the gist of them would all seem to agree that a 40A RCBO is required for a 8.5 KW shower which makes sense as this shower will draw around 36.6 Amps but only 32 Amps is fitted when using 6 MM2 cable, the 32 amp rating will carry the 36.6 amps for a certain time period before tripping and as most showering periods are relatively short then it (usually) wont trip.
Edit: yes I should think that there shouldnt be a problem using a 50 Amp rated pull cord switch with a 32 Amp RCBO as it is the 32 Amp that is the protective device.

John T Carroll

Keith186 wrote: »

Hi John, MCB did not trip at the board at all, only the pull cord switch did. There is an RCBO on the fuse board (also didn't trip).

I meant to mention this the other day even though it has nothing to do with your problem per se.
From the above I take it that the RCBO is also protecting the shower from an earth leakage poin of view??.
This might be perfectly normal, in my own house, a 30 Ma RCD (rated at 63A monitors everything in my house apart from my 9.5 KW shower. The shower is protected via a 40A/30Ma RCBO which is fed directly from the ESB Fuse. In other words I can switch out the house power via the RCD or it might trip but the shower is still live and vica versa ie the shower could cause the RCBO to trip but the house will still have power. My house is 44 years old with the shower installed 10 years ago but I'm pretty sure that my daughter,s 10 year old house is wired similarly but I could be wrong.
In the interests of safety, if you already havnt done so, you might just consider tripping the RCBO and ensure that the shower supply is also dead because if it isnt, it means that you have no earth leakage protection on your shower, apoligies for being a bit long winded.

Sleeper12

While you slightly changed the subject I thought I'd mention that your immersion, gas boiler, power shower & just about anything to do with water should be protected by an rcbo.
I'm not near a fusebox to check but I think if you kill the power to the fusebox the shower won't have power either. I'm not an electrician & there's plenty here to correct me if I'm wrong but I think if you kill power to the board you're rcbo will be dead too.

Keith186

Inspected the unit today. Live wire on the supply side was scorched on closer inspection.

Cleaned with wire brush and connected back up. Did not work at all (dirty inside the terminal). Had bought a new switch earlier just in case so put the new one on and it's working OK. I want to check it again to make sure there's no scorching anywhere. When would you recommend to do so, a couple of weeks maybe?

Old switch was 50A and looked to be fairly good quality. Replacement one is only 45A but connected up good and tight.

I've only one RCBO and when I press the test button it kills power to the shower/sockets/alarm. I noticed that two earth wires in the pull switch are joined to each other instead of the two terminals on the switch.

Thanks for all the help lads, appreciate it!

John T Carroll

Keith186 wrote: »

Inspected the unit today. Live wire on the supply side was scorched on closer inspection.

Cleaned with wire brush and connected back up. Did not work at all (dirty inside the terminal). Had bought a new switch earlier just in case so put the new one on and it's working OK. I want to check it again to make sure there's no scorching anywhere. When would you recommend to do so, a couple of weeks maybe?

Old switch was 50A and looked to be fairly good quality. Replacement one is only 45A but connected up good and tight.

I've only one RCBO and when I press the test button it kills power to the shower/sockets/alarm. I noticed that two earth wires in the pull switch are joined to each other instead of the two terminals on the switch.

Thanks for all the help lads, appreciate it!

You can find with some terminal connections that the screw doesn't actually pinch the wire but either pierces it or is only resting against the side of it even though its tightened. There shouldn't be any problem in my opinion in using a 45A as you are using it properly, it is never making and breaking the 36 Amps or so as you are closing the contacts before switching on the shower and switching off the shower before opening the contacts. It might be no harm just to check the terminal screw tightness after a week or so as they always seem to relax a little and you will always get another bit of a squeeze on them.

Re the RCBO earth protection, I think I have seen (maybe its a new regulation) on a few installations a separate RCD feeding the socket MCBs and a either a separate RCBO feeding the shower or a separate RCD feeding a MCB for the shower but you are protected I would think at any rate, anyway you will soon be told if not by some of the very knowledgeable electrical people here.

Thanks for the feed back Keith as it might help someone else in the future.

Keith186

Thanks John. Next time I'm up in the attic I'm going to see if it's possible that I pushed the attic door against the cable. Still think it's too much of a coincidence! I always push the door over towards that direction so could've caused this all myself when fixing the ballcock.