My Wickes room stat had failed (again) - the knob no longer grips the
metal shaft and so cannot set the temp without using pliers :-)

I want to replace with a better unit but I only have the following
wire connections (from a term box of course):

Safety Ground (Earth)
Switched Live from the Timer for heating
Feed to fire the boiler for heating

I do not have a fixed live or Neutral connection locally.

Any ideas on what I could use or do ??

On 7 Dec 2003 11:46:38 -0800, (BIC) wrote:

My Wickes room stat had failed (again) - the knob no longer grips the
metal shaft and so cannot set the temp without using pliers :-)

I want to replace with a better unit but I only have the following
wire connections (from a term box of course):

Safety Ground (Earth)
Switched Live from the Timer for heating
Feed to fire the boiler for heating

I do not have a fixed live or Neutral connection locally.

Any ideas on what I could use or do ??

Go for an electronic one like a Honeywell CM67

These are far better than any of the bimetallic mechanical types and
will work without a neutral, or indeed an earth.
There is a small battery to run the thermostat and timer function





..andy

To email, substitute .nospam with .gl

(BIC) wrote:

Hello BIC

B| My Wickes room stat had failed (again) - the knob no longer
B| grips the metal shaft and so cannot set the temp without
B| using pliers :-)

Got any solvent left over from waste pipes?

Dab of that on the spindle, refit the knob and leave for five minutes,
jobsa.

--
Simon Avery, Dartmoor, UK
uk.d-i-y FAQ: http://www.diyfaq.org.uk/

"BIC" wrote in message
m...
My Wickes room stat had failed (again) - the knob no longer grips the
metal shaft and so cannot set the temp without using pliers :-)

I want to replace with a better unit but I only have the following
wire connections (from a term box of course):

Safety Ground (Earth)
Switched Live from the Timer for heating
Feed to fire the boiler for heating

I do not have a fixed live or Neutral connection locally.

Any ideas on what I could use or do ??

Randal TP5 (or similar) should do the trick. On offer at £30
http://tinyurl.com/y5e9

HTH
Rob

"BIC" wrote in message
m...
My Wickes room stat had failed (again) - the knob no longer grips the
metal shaft and so cannot set the temp without using pliers :-)

I want to replace with a better unit but I only have the following
wire connections (from a term box of course):

Safety Ground (Earth)
Switched Live from the Timer for heating
Feed to fire the boiler for heating

I do not have a fixed live or Neutral connection locally.

Any ideas on what I could use or do ??

You could go for a three wire option. This is supposed to be more
economical, on certain makes of boilers. If you buy a double-insulated
room-stat ( Drayton Combi-Stat, for instance, £12 ), then you can use the
earth connection as the neutral; best to sleeve it with something to show
it's not an actual earth anymore. I assume the other end of the earth wire
emerges at or near your boiler/timer, and can be patched in to your boiler's
neutral connection ( if it has one ).

Andy

andrewpreece wrote:

snip
then you can use the
earth connection as the neutral; best to sleeve it with something to show
it's not an actual earth anymore. I assume the other end of the earth wire
emerges at or near your boiler/timer, and can be patched in to your boiler's
neutral connection ( if it has one ).

Nooooooo!!!! Most definitely not acceptable. Either use a 'stat which
doesn't need a neutral, or replace the cable with triple + earth.

"Ade" wrote in message
...


andrewpreece wrote:

snip
then you can use the
earth connection as the neutral; best to sleeve it with something to
show
it's not an actual earth anymore. I assume the other end of the earth
wire
emerges at or near your boiler/timer, and can be patched in to your
boiler's
neutral connection ( if it has one ).

Nooooooo!!!! Most definitely not acceptable. Either use a 'stat which
doesn't need a neutral, or replace the cable with triple + earth.


I was given the advice to reuse the earth by H____________l !!!!!!

James Salisbury wrote:

"Ade" wrote in message
...

andrewpreece wrote:

snip
then you can use the
earth connection as the neutral; best to sleeve it with something to show
it's not an actual earth anymore. I assume the other end of the earth wire
emerges at or near your boiler/timer, and can be patched in to your boiler's
neutral connection ( if it has one ).

Nooooooo!!!! Most definitely not acceptable. Either use a 'stat which
doesn't need a neutral, or replace the cable with triple + earth.

I was given the advice to reuse the earth by H____________l !!!!!!

Jeez, that's bad (and probably highly negligent on their part)! Apart
from it being likely to confuse anyone else who works on it, I'm pretty
sure that the Regs require all cables carrying mains voltage to contain
an earth conductor. I'm sure I've even seen an insulated & sheathed red
'single' which contained an ECC used in a lighting circuit on a new
build a few years back...

"Ade" wrote in message
...


andrewpreece wrote:

snip
then you can use the
earth connection as the neutral; best to sleeve it with something to
show
it's not an actual earth anymore. I assume the other end of the earth
wire
emerges at or near your boiler/timer, and can be patched in to your
boiler's
neutral connection ( if it has one ).

Nooooooo!!!! Most definitely not acceptable. Either use a 'stat which
doesn't need a neutral, or replace the cable with triple + earth.

My combi instructions specifies flexible wire for all connections to it (
the
wires go to a drop down panel which causes the wires to flex a little when
opened ).
Attempts to find a flexible triple cored wire in the DIY places failed, and
three core
plus earth is not in the flexible category. I considered it dangerous to use
non-flexible
cable in a flexible situation. I used flexible three core and sleeved the
earth wires to indicate their change of use ( in the same way that a neutral
line
can become a switched live and thus requires a red sleeve ). One recognises
an
earth core by the colour of its insulation. By placing a sleeve on it you
change its
identity, hence its function. I suppose that someone will say that this
is against the law; so, don't do it then!

How to square this circle?

Two wire roomstats have the disadvantage ( I understand ) of large over-and
undershoots of the temperature, +/- 3 degrees C being cited. This can be
noticeable, and is not as economical as the three wire roomstat ( which
contains an anticipator ), and can offer +/- 0.5 degree C stability,
allegedly.
I don't therefore wish to use a two wire connection.

Short of ordering specialist cable the only option I can see is to use TWO
three
core cables, i.e. six cores where only three are required; seems daft to me,
slavishly following regs and doubling the amount of cable needed, especially
for domestic use, where the change of use is signalled by sleeving. I know
the
regs are intended to prevent accidents, but common sense should be a guide
as well. Otherwise we should all be writing out hazard assessments and doing
COSHH inventories in our kitchens etc.

I should mention that the combi/roomstat are both on an RCD protected
spur.

This message should in no way be taken as advice to ignore the electrical
regulations..................

Andy.

In article ,
andrewpreece wrote:
Short of ordering specialist cable the only option I can see is to use
TWO three core cables, i.e. six cores where only three are required;
seems daft to me, slavishly following regs and doubling the amount of
cable needed, especially for domestic use, where the change of use is
signalled by sleeving. I know the regs are intended to prevent
accidents, but common sense should be a guide as well.

Any half decent wholesaler should have various types of multi-core for
just this purpose and sell it by the metre.

TLC prices:-

0.70 per metre for 4 core 0.5mm
0.80 5 core """""
1.90 7 core 0.75

--
*Don't squat with your spurs on *

Dave Plowman London SW 12
RIP Acorn

"andrewpreece" wrote
| My combi instructions specifies flexible wire for all connections to it
| (the wires go to a drop down panel which causes the wires to flex a
| little when opened ).
| Attempts to find a flexible triple cored wire in the DIY places failed,
| and three core plus earth is not in the flexible category.

Maplin XR48C / MW62S 4-core mains flex 0.75mm 6A per m or per reel
GF71N / MW63T ditto 1.25mm 13A

Brown / blue / black / green-yellow in a black rubber sheath.

Bl**dy one pound forty-nine a metre through.

Owain

Safety Ground (Earth)
Switched Live from the Timer for heating
Feed to fire the boiler for heating

Replace with a digital thermostat. Much more accurate than analogue types.
Almost all digital thermostats only require the timer live (in) and demand
for heat (out) connections. Earth, neutral and permanent live are not
usually required.

The earth may be a neutral for an old analogue thermostat, naughtily using
the green/yellow or bare conductor. In any case, the digital thermostat
won't need it, so it can be ignored, provided it is tucked away safely
insulated.

Christian.

Two wire roomstats have the disadvantage ( I understand ) of large
over-and undershoots of the temperature, +/- 3 degrees C being
cited.

Use a digital thermostat. These operate on two wires and frequently have
complex microprocessor based control theory implementations that antipate
better than any analogue contraption. If you install a programmable one, you
can vary the temperature at different times of day, and they are often
installed in convenient locations for programming, rather than at the back
of a dark cupboard full of cr*p.

Christian.