Triton T80xr shower faulty

[Pete Zahut]

Wife was in the shower this morning when it stopped working. Went down to the consumer unit to discover that it hadn't tripped it's own individual MCB but it had tripped the 30mA RCD - reset RCD and all other circuits fed by it are fine; shower solenoid valve operates so that we now get water flow but water doesn't heat up at all.

First point - I know that there is a thermal cutout but can't see any obvious signs that it has operated, nor any obvious means to reset it if it has - or is it a self-resetting device, ie, does it operate until the temperature drops down to safe levels and then reset itself? Any way of testing these?

Second point - Would a thermal cutout problem trip the RCD? I'm no electrician by any means but my very limited knowledge of RCDs and the way they sense imbalances is sort of pointing me towards a possible heating element failure, ie, element casing fails and water gets into lecktrickery-carrying parts allowing current to leak to earth, thereby tripping the RCD.

I suppose this is easy enough to test for by connecting a multimeter between the copper body of the heater can assembly and the heating element terminals, but what sort of values would indicate a faulty/non-faulty condition?

Could it be something else entirely?

TIA,

Pete

[Jim]

"Pete Zahut" wrote: [RCD problems]

Yes. It depends on your RCD, but immersion or shower water heaters and dishwashers/washing machine all produce a certain amount of leakage current, also things with switch-mode PSUs such as PCs.

We had a situation where we had enough PCs plugged in that the washing machine starting its cycle would trip the RCD: but it wasn't the RCD or the washing machine which was faulty, IYSWIM.

[Clive George]

Why should a switch-mode PSU produce leakage current? Inductance?

[Jim]

It's to do with current leakage through the capacitors in the EMC filters. This page describes in far better detail than I can convey here:

it to say, you get about 2-3mA leakage per device, so it can add up with multiple devices enough to trip out a 30mA RCD.

I am not sure this is the OP's problem, though, if his shower is still refusing to give out heat after the RCD has been reset.

[Pete Zahut]

Thanks for the response but no, I don't think it has anything to do with that because at 7.00am there's not many things switched on (an hour later and there's all sorts of things switched on, but not at that time) and those same things have been switched on at that time of day for years, ie, her in shower, me in kitchen making coffee and toast and that's about it.

Pete

[John Rumm]

Chances are the heating element has failed, and for a brief time at least was causing a live to earth short.

Don't know, but it should be easy enough to test...

Indeed - far more probable.

Firstly what is the state now? Does the shower work at all (i.e. does the solenoid still work and water flow (albeit cold))?

There are a few tests you can do....

(Obviously make sure the shower is isolated from the mains before going any further)

Referring to the parts diagram here:

if you can take a measurement between the contacts on the thermal cutout. Using a low resistance range, you should see a resistance of to all intents and purposes zero. If it is open circuit then there is one failure. However It would be wise to attempt to work out why it cutout rather than just replacing it.

Next measure between the two ends of the heating element. You should see a low but non zero resistance. Say your shower is a 9.5kW one this would be something like 240^2 / 240 or about 6 ohms. If it is significantly higher than this then that suggests an element failure.

Now using your highest resistance range measure between both ends of the heater terminals and the earth conductor. You should see an open circuit here or at least a very high resistance >= 2MOhms. (note this is not a definitive test, in that there are cases where the breakdown of the insulation is only evident at much higher voltages that a standard multimeter is capable of testing at)

Check power is reaching the shower in the first place - its indicator lights come on etc.

[Pete Zahut]

Yes, the solenoid works and water is flowing but is not being heated at all.

> see if you can take a measurement between the contacts on the thermal

As above. Power reaching shower and solenoid operating to allow water flow but water not being heated. Thanks for that info John, I'll test it later.

Pete

[John Rumm]

>>> see if you can take a measurement between the contacts on the thermal

In which case it sounds like an element failure, or possibly the controller has failed.

[The Medway Handyman]

I've been through about 2 Triton T80's in the past. IME its cheaper to replace than buy spares & bugger about.

[Grimly Curmudgeon]

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember "The Medway Handyman" saying something like:

Ding. I've found that too. On dismantling and re-assembly you often find leaks where none existed before, as elderly O-rings don't like being disturbed and some of them are odd sizes, so have to be re-used. An overhaul kit, if available, would contain all the small bits that go wonky, but given the rapacious nature of the spares business would tilt it even more towards the bin.

[Bill]

MMMMMMmmmmmmm I have Triton, fairly sure it is an early T80. I've had one heater fail in 10 years and about six microswitches. It is used daily and has had a hard life. For me to replace a microswitch now takes about 15 minutes.

As a slightly off topic comment, when I moved into this house the shower was totally naff and didn't get particularly hot. It was fed from a fused spur just outside the shower room, fitted with a 13A fuse, the fuse went after about a month, which is when I found it. There was also about 30' of 2.5mm cable from the CU feeding it, some diagonally across a wall buried in plaster. Not sure the previous owner had a clue!!!!!!!!!!!

Replaced cable, fitted ceiling pull switch and fitted dedicated mcb in the CU, felt a lot happier, and had much hotter shower. House now totally rewired as well. Too many horrors to go into now...

[Alang]

Same here. Fix one thing then a few weeks later something else goes. HAppened to me twice. When our current one shows signs of fault it will be replaced by a brand new one. I only wish I'd bought a spare when they were on special offer at half price

[Pete Zahut]

Right, after reading the other posts and giving it some thought we're leaning towards replacement rather than repair. Thing is, SWMBO is now making noises about converting it to a mixer system plumbed into the hot/cold water pipes and running off the combi instead of another electric shower. It should actually be easy enough to do as it's a shower over the bath rather than a shower cubicle so the piping is in easy reach as it were.

But what is a shower like when fed from a combi? We have an Alpha CD32C condensing combi in the loft which gives us good hot water at good (I would guesstimate almost mains) pressure - is it suitable/desirable to run a shower from that? What about connecting a shower pump to turn it into a 'power shower', or would it be powerful enough as we get very good pressure from it anyway? I suppose whatever pressure it's at it'll be a more powerful flow than what comes out of the 10.5kW leccy one?

Cheers folks

[Pete Zahut]

Glad the house is now fully rewired Bill :o)

With my luck, there'll be other problems so I think we're going to go down the replace rather than repair path.

[PeterC]

I rewired one like that. It had been used on the Low setting (amazing how long a 13A fuse will last at 14 - 15A) and the 2.5mm had glass-fibre stuck in it! I cut the cable in to ~6" pieces so that it couldn't be re-used and wired the unit with 6mm.

[Bob Mannix]

Combi showers are very good (aside from someone turning on the kitchen tap). They are powerful (enough) and never ending. Most folks agree on that. It's baths/2 bathrooms etc where they fall down somewhat.

[Alang]

Someone turning on the kitchen tap while the bath is being filled is the reason we stuck with an electric shower rather than one plumbed into the combi supply. There is almost a complete loss of pressure to the upper floor.

[Grimly Curmudgeon]

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember PeterC saying something like:

I came across one like that, in a builder's own house he'd sold on. The new owners asked me to check out the shower and I found it was a mains pressure shower fed from a tank. Just as well the low pressure interlock had prevented the thing from working, because it was fed with 2.5mm T&E all the way across the loft floor and under some fairly flammable materials.

It's when I see crap like that I can agree with the trumpeted aims of Part P, if not the implementation of it. Part P wouldn't have prevented the utter nobber from doing it, though. Oh, and the same house had a defective -as in fail dangerous - RCD.