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

"Pete Zahut" dont@bother wrote:
[RCD problems]
Could it be something else entirely?

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.

"Jim" wrote in message
...
"Pete Zahut" dont@bother wrote:
[RCD problems]
Could it be something else entirely?

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.

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

"Clive George" wrote:
"Jim" wrote in message
...
"Pete Zahut" dont@bother wrote:
[RCD problems]
Could it be something else entirely?

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.

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

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
he

http://www.marcspages.co.uk/pq/3333.htm

Suffice 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.

Jim wrote:
"Clive George" wrote:
"Jim" wrote in message
...
"Pete Zahut" dont@bother wrote:
[RCD problems]
Could it be something else entirely?

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.

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

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
he

http://www.marcspages.co.uk/pq/3333.htm

Suffice 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.

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

Pete Zahut wrote:

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.

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

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?

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

Second point - Would a thermal cutout problem trip the RCD? I'm no

Its unlikely...

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.

Indeed - far more probable.

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?

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 he

http://www.onlineplumbingsupplies.co...er_Spares.html

see 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)

Could it be something else entirely?

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



--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

John Rumm wrote:
Pete Zahut wrote:

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.

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

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?

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

Second point - Would a thermal cutout problem trip the RCD? I'm no

Its unlikely...

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.

Indeed - far more probable.

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?

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

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

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 he

http://www.onlineplumbingsupplies.co...er_Spares.html

see 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)

Could it be something else entirely?

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

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

Pete Zahut wrote:
John Rumm wrote:
Pete Zahut wrote:

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

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

Second point - Would a thermal cutout problem trip the RCD? I'm no
Its unlikely...

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.
Indeed - far more probable.

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

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

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 he

http://www.onlineplumbingsupplies.co...er_Spares.html

see 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)

Could it be something else entirely?
Check power is reaching the shower in the first place - its indicator
lights come on etc.

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.

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

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

Pete Zahut wrote:
Wife was in the shower this morning when it stopped working.

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


--
Dave - The Medway Handyman
www.medwayhandyman.co.uk

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:

Pete Zahut wrote:
Wife was in the shower this morning when it stopped working.

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

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.

In message , The Medway
Handyman writes
Pete Zahut wrote:
Wife was in the shower this morning when it stopped working.

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


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...
--
Bill

On Thu, 19 Feb 2009 01:08:37 +0000, Grimly Curmudgeon
wrote:

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:

Pete Zahut wrote:
Wife was in the shower this morning when it stopped working.

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

Ding.
I've found that too.

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

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.

Alang wrote:
On Thu, 19 Feb 2009 01:08:37 +0000, Grimly Curmudgeon
wrote:

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:

Pete Zahut wrote:
Wife was in the shower this morning when it stopped working.

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

Ding.
I've found that too.

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

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.

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

Bill wrote:
In message , The
Medway Handyman writes
Pete Zahut wrote:
Wife was in the shower this morning when it stopped working.

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


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...

Glad the house is now fully rewired Bill )

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

On Thu, 19 Feb 2009 02:04:13 +0000, Bill wrote:

In message , The Medway
Handyman writes
Pete Zahut wrote:
Wife was in the shower this morning when it stopped working.

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


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!!!!!!!!!!!

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.

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...


--
Peter.
You don't understand Newton's Third Law of Motion?
It's not rocket science, you know.

"Pete Zahut" dont@bother wrote in message
...
Alang wrote:
On Thu, 19 Feb 2009 01:08:37 +0000, Grimly Curmudgeon
wrote:

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:

Pete Zahut wrote:
Wife was in the shower this morning when it stopped working.

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

Ding.
I've found that too.

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

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.

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?


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.


--
Bob Mannix
(anti-spam is as easy as 1-2-3 - not)

On Thu, 19 Feb 2009 15:27:45 -0000, "Bob Mannix"
wrote:

"Pete Zahut" dont@bother wrote in message
...
Alang wrote:
On Thu, 19 Feb 2009 01:08:37 +0000, Grimly Curmudgeon
wrote:

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:

Pete Zahut wrote:
Wife was in the shower this morning when it stopped working.

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

Ding.
I've found that too.

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

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.

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?


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.

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.

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

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!!!!!!!!!!!

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 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.