Hi,

The CH and HW is driven by a Danfoss 24-hour `clock face' timer that has
two on-off periods a day. It's six terminals seem to be wired

1 switched live output
2 unused
3 switched live input, connected from 6
4 earth, not connected - is this normal?
5 neutral
6 live

I'm looking for a digital replacement so I can time things more
accurately. Do these things typically fit to a standard backplate so
the existing hole in the wall can be re-used?

My main reason for posting is I'd like more on-off periods a day but 3-4
seems to be the maximum. Anyone know of a 24-hour, or maybe 7-day,
timer that has more, e.g. 6?

Thanks.

Sam.

Hi


"Sam Norris" wrote in message
...
Hi,

The CH and HW is driven by a Danfoss 24-hour `clock face' timer that has
two on-off periods a day. It's six terminals seem to be wired

1 switched live output
2 unused
3 switched live input, connected from 6
4 earth, not connected - is this normal?
5 neutral
6 live

I'm looking for a digital replacement so I can time things more
accurately. Do these things typically fit to a standard backplate so
the existing hole in the wall can be re-used?

My main reason for posting is I'd like more on-off periods a day but 3-4
seems to be the maximum. Anyone know of a 24-hour, or maybe 7-day,
timer that has more, e.g. 6?


Hi Most now do 3 time zones and 7 day mine came from screwfix and combined
with a digital stat that has 2 periods this combination should be enough
for any one. and the mostly do use the standard plate.

Ian

On 30 Nov 2003 18:53:25 GMT, Sam Norris wrote:

I'm looking for a digital replacement so I can time things more
accurately. Do these things typically fit to a standard backplate
so the existing hole in the wall can be re-used?

Most now fit onto a single gang box but also overlap varying amounts
left and/or right, top and/or bottom. If you have 6" clearance all
round from the edge of current plate that shouldn't be an issue.

There has been some standardisation on back plates over recent years.
One of the makers has a nice free booklet that details old controllers
and their wiring and how to wire up to (their) new controllers. This
is from Horstmann I think.

My main reason for posting is I'd like more on-off periods a day but
3-4 seems to be the maximum. Anyone know of a 24-hour, or maybe
7-day, timer that has more, e.g. 6?

I can't see a reason for more than about 3 HW periods(*) morning,
lunch & evening. If you want better control on the CH then you'd be
better off looking at a programmable thermostat, these typically have
6 set temperatures through the day and each day can be different. The
more recent and cheaper programmable stats are a little more limited
in the temps/times etc than the older ones such as the Danfoss TP75 or
Honeywell CM67.

However you need to investigate the wiring of your time control and
existing thermostats (both HW cylinder and room) as it appears you
only have simple ON/OFF control for HW *and* CH from your current
controller.

(*) I have reservations about having HW on a regular time (morning &
evening) control. It can waste significant amounts of fuel, depending
on your life style. I had a simple mechanical timer on the HW/CH it
broke but at the time I was living alone, the HW tank was well
insulated and would last 2 days hot enough for washing/washing up. If
I wanted a bath I'd manually switch on the boiler, reheat time was
about 20mins. There was about =A310/qtr reduction in may gas bill
between having the timer and manual system. Needless to say they timer
didn't get replaced until I sold and moved out of that flat...

--
Cheers
Dave. pam is missing e-mail

A cylinder thermostat is a good idea.

--


Regards

John

"Dave Liquorice" wrote in message
. 1...
On 30 Nov 2003 18:53:25 GMT, Sam Norris wrote:

I'm looking for a digital replacement so I can time things more
accurately. Do these things typically fit to a standard backplate
so the existing hole in the wall can be re-used?

Most now fit onto a single gang box but also overlap varying amounts
left and/or right, top and/or bottom. If you have 6" clearance all
round from the edge of current plate that shouldn't be an issue.

There has been some standardisation on back plates over recent years.
One of the makers has a nice free booklet that details old controllers
and their wiring and how to wire up to (their) new controllers. This
is from Horstmann I think.

My main reason for posting is I'd like more on-off periods a day but
3-4 seems to be the maximum. Anyone know of a 24-hour, or maybe
7-day, timer that has more, e.g. 6?

I can't see a reason for more than about 3 HW periods(*) morning,
lunch & evening. If you want better control on the CH then you'd be
better off looking at a programmable thermostat, these typically have
6 set temperatures through the day and each day can be different. The
more recent and cheaper programmable stats are a little more limited
in the temps/times etc than the older ones such as the Danfoss TP75 or
Honeywell CM67.

However you need to investigate the wiring of your time control and
existing thermostats (both HW cylinder and room) as it appears you
only have simple ON/OFF control for HW *and* CH from your current
controller.

(*) I have reservations about having HW on a regular time (morning &
evening) control. It can waste significant amounts of fuel, depending
on your life style. I had a simple mechanical timer on the HW/CH it
broke but at the time I was living alone, the HW tank was well
insulated and would last 2 days hot enough for washing/washing up. If
I wanted a bath I'd manually switch on the boiler, reheat time was
about 20mins. There was about £10/qtr reduction in may gas bill
between having the timer and manual system. Needless to say they timer
didn't get replaced until I sold and moved out of that flat...

--
Cheers
Dave. pam is missing e-mail





---
All of my outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.545 / Virus Database: 339 - Release Date: 27/11/2003

Hi Most now do 3 time zones and 7 day mine came from screwfix and
combined with a digital stat that has 2 periods this combination
should be enough for any one. and the mostly do use the standard plate.

A have a programmable room thermostat (Sunvic) which can have up to 12
on-off periods a day. However, it can only be switched an hourly intervals.
You'd need to replace your room thermostat with it and set your original
programmer to always on.

Christian.

On Sun, 30 Nov 2003 20:21:47 -0000, John wrote:

A cylinder thermostat is a good idea.

Now if you'd posted properly, below the section of the post that you
are refering to and trimmed out anything not relevant I wouldn't have
to guess as to which part you are commenting.

1/10 please try again.

--
Cheers
Dave. pam is missing e-mail

"Dave Liquorice" wrote in message .1...
On 30 Nov 2003 18:53:25 GMT, Sam Norris wrote:

I'm looking for a digital replacement so I can time things more
accurately. Do these things typically fit to a standard backplate
so the existing hole in the wall can be re-used?

Most now fit onto a single gang box but also overlap varying amounts
left and/or right, top and/or bottom. If you have 6" clearance all
round from the edge of current plate that shouldn't be an issue.

There has been some standardisation on back plates over recent years.
One of the makers has a nice free booklet that details old controllers
and their wiring and how to wire up to (their) new controllers. This
is from Horstmann I think.

I think that although the back plates are pretty standardised now,
unfortunately they weren't when the Danfoss mechanical timer was
designed. I remember years ago trying to do what you want to, and in
the absence of any decent wiring instructions I found the whole jumble
of wires behind the controller so confusing I ended up refitting the
Danfoss and giving up on the idea!

Have a browse around www.tlc-direct.co.uk though - they have some very
useful reference material on CH timers amongst other things.

David

In message , Sam Norris
writes
Hi,

The CH and HW is driven by a Danfoss 24-hour `clock face' timer that has
two on-off periods a day.

Any one in particular?

It's six terminals seem to be wired

1 switched live output
2 unused
3 switched live input, connected from 6
4 earth, not connected - is this normal?
5 neutral
6 live

I'm looking for a digital replacement so I can time things more
accurately. Do these things typically fit to a standard backplate so
the existing hole in the wall can be re-used?

My main reason for posting is I'd like more on-off periods a day but 3-4
seems to be the maximum. Anyone know of a 24-hour, or maybe 7-day,
timer that has more, e.g. 6?

Thanks.

Sam.

--
geoff

"Christian McArdle" wrote
Hi Most now do 3 time zones and 7 day mine came from screwfix and
combined with a digital stat that has 2 periods this combination
should be enough for any one. and the mostly do use the standard plate.

A have a programmable room thermostat (Sunvic) which can have up to 12
on-off periods a day. However, it can only be switched an hourly intervals.
You'd need to replace your room thermostat with it and set your original
programmer to always on.

I'm confused with the CH in my house.

I have one timer, a cylinder thermostat, and the main thermostat on
the boiler, but no room thermostat.

I have TRV's on all rads, but the lack of a room thermostat bothers
me.

Should it ?!

Cheers,

Paul.

Hi Geoff,

The CH and HW is driven by a Danfoss 24-hour `clock face' timer that
has two on-off periods a day.

Any one in particular?

Does "Danfoss 103" mean anything?

Sam.

Hi Ian/Christian,

Christian wrote:
Ian wrote:
Most now do 3 time zones and 7 day mine came from screwfix and
combined with a digital stat that has 2 periods this combination
should be enough for any one. and the mostly do use the standard
plate.

A have a programmable room thermostat (Sunvic) which can have up to 12
on-off periods a day. However, it can only be switched an hourly
intervals. You'd need to replace your room thermostat with it and set
your original programmer to always on.

The system doesn't have a room thermostat and I don't wish to add one
given the current task in hand. All I need is a more precise timer,
e.g. on at 7am sharp for 90 minutes, and more on/offs a day. Three
on/offs wouldn't really be much of an improvement over my current two.
Any other ideas?

Thanks,

Sam.

Hi Dave,

Dave wrote:
On 30 Nov 2003 18:53:25 GMT, Sam Norris wrote:
I'm looking for a digital replacement so I can time things more
accurately. Do these things typically fit to a standard backplate
so the existing hole in the wall can be re-used?

Most now fit onto a single gang box but also overlap varying amounts
left and/or right, top and/or bottom. If you have 6" clearance all
round from the edge of current plate that shouldn't be an issue.

OK, I haven't clearance on the left but at least I know now what to
watch out for.

My main reason for posting is I'd like more on-off periods a day but
3-4 seems to be the maximum. Anyone know of a 24-hour, or maybe
7-day, timer that has more, e.g. 6?

I can't see a reason for more than about 3 HW periods(*) morning,
lunch & evening. If you want better control on the CH then you'd be
better off looking at a programmable thermostat, these typically have
6 set temperatures through the day and each day can be different. The
more recent and cheaper programmable stats are a little more limited
in the temps/times etc than the older ones such as the Danfoss TP75 or
Honeywell CM67.

I really am limited to replacing the existing timer with another timer.

However you need to investigate the wiring of your time control and
existing thermostats (both HW cylinder and room) as it appears you
only have simple ON/OFF control for HW *and* CH from your current
controller.

That's correct; the timer has no selection over HW or CH as per my
wiring suggestion. And I don't have a room thermostat.

(*) I have reservations about having HW on a regular time (morning &
evening) control. It can waste significant amounts of fuel, depending
on your life style.

The HW cylinder is zoned off; the two-port valve is controlled by a
cylinder thermostat. So I use the simple timer to say `make sure
everything that wants heat gets it' and if the HW is satisfied then only
the rads get heat, and they're TRV'd.

The boiler only goes active if a flow sensor downstream of the pump
detects significant flow indicating either the HW circuit is open, or
sufficient TRVs are open. If all TRVs are closed, and the HW satisfied,
there's a by-pass before the flow sensor.

Hope this makes it clearer. Looks like there may not be a timer with
the number of on/offs I need. Could a room stat do the task if I set
the required temp. such that it was never met? That is, would it fit in
with the existing wiring?

Thanks,

Sam.

On 4 Dec 2003 00:11:04 GMT, Sam Norris wrote:

Hope this makes it clearer.

Yep, bit non-standard but if it works...

Looks like there may not be a timer with the number of on/offs I
need.

One solution would be a plugin timer of the sort that you move lugs
in/out or insert pins into to set on/off times. Not particulary
elegant or easy to to wire into your existing cabling but not
impossible.

Best bet is to dig about on the various manufactures websites, google
is your friend. Remember if you get a CH HW controller with 3
independant periods/day you could parallel the contacts and get 6
periods. Horstman do a 3 channel timer...

Could a room stat do the task if I set the required temp. such that
it was never met?

In which case it would always be on... A programable room stat turns
on/off in response to the rooms temperature, the time element controls
the times that a given temperature is set. eg. 0700 0900 20C, 0900
1600 18.5C, 1600 2300 21C, 2300 0700 15C.

I think my TP75 has an "off" setting as well as various temperatures
but to use it just as a time switch would be a little wasteful.

--
Cheers
Dave. pam is missing e-mail

I have TRV's on all rads, but the lack of a room thermostat bothers
me.

Should it ?!

It is permissible to have all TRVs instead of a room thermostat and TRVs in
other rooms. However, your system should have a boiler interlock. This turns
off the boiler when all the TRVs are closed. This is done with a flow switch
on the boiler automatic bypass, or on the central heating circuit. Your
system may not have such a bypass or flow switch, in which case it may be
inefficient. Also, without an automatic bypass, you may find that the pump
overrun is ineffective, which can cause problems for your boiler.

Christian.

Hi David,

David wrote:
"Dave Liquorice" wrote:
There has been some standardisation on back plates over recent
years. One of the makers has a nice free booklet that details old
controllers and their wiring and how to wire up to (their) new
controllers. This is from Horstmann I think.

I think that although the back plates are pretty standardised now,
unfortunately they weren't when the Danfoss mechanical timer was
designed. I remember years ago trying to do what you want to, and in
the absence of any decent wiring instructions I found the whole jumble
of wires behind the controller so confusing I ended up refitting the
Danfoss and giving up on the idea!

Been there, and think I've figured out what the wiring is doing.

There's L, N, and E supplied through a fused switch. L and N supply 5
and 6 on the Danfoss timer.

1 switched live output
2 unused
3 switched live input, connected from 6
4 earth, not connected - is this normal?
5 neutral
6 live

The LNE also continue up from the kitchen to the control unit in the
airing cupboard. From there another cable comes down which is used for
L, N, and E for the boiler plus a pump-overrun live, and a switched
live.

Have a browse around www.tlc-direct.co.uk though - they have some very
useful reference material on CH timers amongst other things.

Thanks, I found this helpful. They have two `Wire-in Time Clocks, Fused
and Switched' --
http://www.tlc-direct.co.uk/Main_Ind...s_1/index.html
-- the 7 day one, FST17 seems to have 6 on/offs a day.

They provide a PDF of the installation instructions that covers both the
FST11 (24 hour) and FST17 (7 day) --
http://www.tlc-direct.co.uk/Technica...iths/FST11.pdf
(470KB) -- which says "A normal switched output is available as well as
the timeswitch output" and refers to Fig. 3. But where's the "normal
switched output" as terminal 1 is the timeswitched live?

Apart from that, it would seem suitable, no? I don't need the fused
switch aspect since there's already one sitting next to the Danfoss
timer but I guess two in series won't do any harm. Alternatively, I
could replace the existed fused switch with the FST17 and just leave the
Danfoss sitting there unused, assuming the cables will reach.

Sam.

Hi Dave,

Dave wrote:
Sam Norris wrote:
Hope this makes it clearer.

Yep, bit non-standard but if it works...

Not my design :-) And it works after a fashion.

Best bet is to dig about on the various manufactures websites, google
is your friend. Remember if you get a CH HW controller with 3
independant periods/day you could parallel the contacts and get 6
periods.

Ah, you mean I've 3 on/offs for HW and 3 independent on/offs for CH, but
in my case they'd both just feed a single switched live through to the
rest of the system. I didn't appreciate that when something like the
Horstmann C27 programmer, Screwfix 11225, says 3 on/offs per 24 hours
that would be 3 for HW and 3 for CH and not 3, each of which can be HW,
CH, or HW+CH.

Horstman do a 3 channel timer...

What does `channel' mean?

Could a room stat do the task if I set the required temp. such that
it was never met?

In which case it would always be on... A programable room stat turns
on/off in response to the rooms temperature, the time element controls
the times that a given temperature is set. eg. 0700 0900 20C, 0900
1600 18.5C, 1600 2300 21C, 2300 0700 15C.

Thanks; see told you I didn't have one :-)

Sam.

Hi Dave,

I wrote:
Dave wrote:
Horstman do a 3 channel timer...

What does `channel' mean?

Ah, one channel is one switched live output. So I've a 1 channel timer
and independent HW and CH needs 2 channels.

Sam.

On 4 Dec 2003 16:00:06 GMT, Sam Norris wrote:

Ah, you mean I've 3 on/offs for HW and 3 independent on/offs for CH,
but in my case they'd both just feed a single switched live through
to the rest of the system.

Yes, you just have to ensure that the programmer has independant
switching for HW and CH, most these days do.

Horstman do a 3 channel timer...

What does `channel' mean?

A switched output.

A programable room stat ...

Thanks; see told you I didn't have one :-)

Wonderful devices, the house is always the right temp, once you've got
it programmed for the correct temps/times it's fit and forget.
Noticable reduction if fuel consumption over a simple room stat/time
switch combination and the house is far more comfortable.

--
Cheers
Dave. pam is missing e-mail