Hi Guys,
My central heating timer is playing up, its a old mechanical clock
type with little pegs to set the On/Off time, make unkown at this
moment. I need some advice on fitting a new digital type timer.
It only needs to control the Central Heating but most timers seem to
do both CH and HW, would one of these be OK.
I think there are 3 mains cables going to the exsiting timer (possibly
one for theromstat, one for the boiler/pump and the mains supply?)
although I'm just guessing!
Can anyone advice a model or explain how to wire a new one up. I can
post more info on my old model when I get home if this helps.

thanks in advance

My central heating timer is playing up, its a old mechanical clock
type with little pegs to set the On/Off time, make unkown at this
moment. I need some advice on fitting a new digital type timer.

Personally, I would replace it with a light switch. Then replace your room
thermostat (or add if not already existing) with a programmable type. There
are significant advantages to doing so. The advantages of a programmable
thermostat a

1. Usually in a more convenient location for programming/override.
2. Enables setback temperatures, so nighttime could be set at 10C, rather
than -273C.
3. Enables thermostat logic to predict the length of time to warm up and so
turn on early on cold days.
4. Prettier.
5. Similar cost.
6. Clock/digital temperature display.

Christian.

"Christian McArdle" wrote in message
et...
My central heating timer is playing up, its a old mechanical clock
type with little pegs to set the On/Off time, make unkown at this
moment. I need some advice on fitting a new digital type timer.

Personally, I would replace it with a light switch. Then replace your room
thermostat (or add if not already existing) with a programmable type.
There
are significant advantages to doing so. The advantages of a programmable
thermostat a

1. Usually in a more convenient location for programming/override.
2. Enables setback temperatures, so nighttime could be set at 10C, rather
than -273C.
3. Enables thermostat logic to predict the length of time to warm up and
so
turn on early on cold days.
4. Prettier.
5. Similar cost.
6. Clock/digital temperature display.

Christian.


And could most likely be used with existing wiring you have, without any
modifications, extensions or additions.

"Christian McArdle" wrote in message . net...
My central heating timer is playing up, its a old mechanical clock
type with little pegs to set the On/Off time, make unkown at this
moment. I need some advice on fitting a new digital type timer.

Personally, I would replace it with a light switch. Then replace your room
thermostat (or add if not already existing) with a programmable type. There
are significant advantages to doing so. The advantages of a programmable
thermostat a

1. Usually in a more convenient location for programming/override.
2. Enables setback temperatures, so nighttime could be set at 10C, rather
than -273C.
3. Enables thermostat logic to predict the length of time to warm up and so
turn on early on cold days.
4. Prettier.
5. Similar cost.
6. Clock/digital temperature display.

Christian.

Hi Christian,
Never thought of that option, now if I understand, could I just leave
the original fulty time just left on constant and control the "new
on/off timer" with a programable thermostat? I can see what you mean
about just change the old one for a switch but don't really understand
the wiring for that. Is it a case of the supply is just swtching the
pump and new thermostat on or off?
Thanks again, meanwhile I'll do a search on a programable thermostat.

Never thought of that option, now if I understand, could I just leave
the original fulty time just left on constant and control the "new
on/off timer" with a programable thermostat?

If the existing one is working to the extent of having a working "always on"
mode, then indeed there is no need to replace with a switch.

Christian.

"Christian McArdle" wrote in message .net...
Never thought of that option, now if I understand, could I just leave
the original fulty time just left on constant and control the "new
on/off timer" with a programable thermostat?

If the existing one is working to the extent of having a working "always on"
mode, then indeed there is no need to replace with a switch.

Christian.

The old timer has just been left on constant and we "turn on/off" the
heating when we get in by the thermostat. Thats fine but now its
getting cold I needed to replace the not working timer, anyway I think
I've found a programmable thermostat and its about £30
http://www.tlc-direct.co.uk/Products/HOSTAT7.html This looks like what
I need.

thanks for you help and a good suggestion, I didn't know these things
exsisted!

Thats fine but now its getting cold I needed to replace the not
working timer, anyway I think I've found a programmable thermostat
and its about £30

There's a whole world of these devices out there. You might want to shop
around to find one with facilities and appearance that suit your decor,
rather than necessarily buying the first one.

Christian.

Christian McArdle wrote:
Thats fine but now its getting cold I needed to replace the not
working timer, anyway I think I've found a programmable thermostat
and its about £30


There's a whole world of these devices out there. You might want to shop
around to find one with facilities and appearance that suit your decor,
rather than necessarily buying the first one.

Christian.




Will you also want to run domestic hot water heating on a timer too? In
that case, a timer/room thermostat alone won't do the job.
Phil.

On Thu, 25 Nov 2004 17:54:27 +0000, "P.R.Brady"
strung together this:

Will you also want to run domestic hot water heating on a timer too?

Read the OP.
--

SJW
A.C.S. Ltd
Please reply to group or use 'usenet' in email subject

"Christian McArdle" wrote in message .net...
Thats fine but now its getting cold I needed to replace the not
working timer, anyway I think I've found a programmable thermostat
and its about £30

There's a whole world of these devices out there. You might want to shop
around to find one with facilities and appearance that suit your decor,
rather than necessarily buying the first one.

Christian.

There is too many to choose so I'll go with my insticts and get that
one, should be here today and I'll have a gone at fitting it tomorrow.
thanks for your advice and I'll let you know if 'm successful!

There is too many to choose so I'll go with my insticts and get that
one, should be here today and I'll have a gone at fitting it tomorrow.
thanks for your advice and I'll let you know if 'm successful!

Note that the existing wiring probably has 3 wires. There is usually a live
input (only when the CH is turned on at the programmer), switched live
output and a neutral. Electronic thermostats do not require the neutral
connection.

This wire should be safely terminated and insulated. The live input goes to
'C' and the switched live output goes to 'NO' or 'NC' depending on whether
the manufacturer considers the normal temperature to be lower or higher than
the setpoint. I think 'NO' would be more common.

Christian.

"Christian McArdle" wrote in message .net...
There is too many to choose so I'll go with my insticts and get that
one, should be here today and I'll have a gone at fitting it tomorrow.
thanks for your advice and I'll let you know if 'm successful!

Note that the existing wiring probably has 3 wires. There is usually a live
input (only when the CH is turned on at the programmer), switched live
output and a neutral. Electronic thermostats do not require the neutral
connection.

This wire should be safely terminated and insulated. The live input goes to
'C' and the switched live output goes to 'NO' or 'NC' depending on whether
the manufacturer considers the normal temperature to be lower or higher than
the setpoint. I think 'NO' would be more common.

Christian.

Well, its arrived and looking at all the various diagrams with it, I'm
not sure!
Basically it has 4 connections: 1-Line, 2-Load Heat, 3-Load Cool, 4-N
parking. So am I correct in thinking just using 2 wires on the
exsisting thermostat (which two as yet I don't know) are connected to
connections 1 and 2? I realise its hard for you to answer when I don't
even know what wires are to the exsisting thermostat, but when I get
into it, it may all become clear!

Thanks again for your help

Well, its arrived and looking at all the various diagrams with it, I'm
not sure!
Basically it has 4 connections: 1-Line, 2-Load Heat, 3-Load Cool, 4-N
parking. So am I correct in thinking just using 2 wires on the
exsisting thermostat (which two as yet I don't know) are connected to
connections 1 and 2?

Put the "permanent" live to '1-line'. Put the switched live to '2-load
heat'. Any spare neutral goes to '4-N parking'. They've been nice enough to
provide a terminal to stick the unwanted neutral on. Nothing goes to '3-load
cooling' unless you've got air conditioning, you b*stard!

If you've only got 2 conductors to deal with, stick them on '1' and '2' at
random. It is only if you've got 3 wires that you have to worry about
identifying which one is neutral.

Christian.

"Christian McArdle" wrote in message .net...
Well, its arrived and looking at all the various diagrams with it, I'm
not sure!
Basically it has 4 connections: 1-Line, 2-Load Heat, 3-Load Cool, 4-N
parking. So am I correct in thinking just using 2 wires on the
exsisting thermostat (which two as yet I don't know) are connected to
connections 1 and 2?

Put the "permanent" live to '1-line'. Put the switched live to '2-load
heat'. Any spare neutral goes to '4-N parking'. They've been nice enough to
provide a terminal to stick the unwanted neutral on. Nothing goes to '3-load
cooling' unless you've got air conditioning, you b*stard!

If you've only got 2 conductors to deal with, stick them on '1' and '2' at
random. It is only if you've got 3 wires that you have to worry about
identifying which one is neutral.

Christian.

Installed fine, no problems, using pins 1 and 2, neutral on pin 4.
Thanks for your advice, I'm really pleased, heating on when I get up
and when I get home!

cheers