I was looking for a very simple optimiser "timer" control panel that
can be fitted to a domestic gas powered central heating system.

It is a combi - instant hot water boiler.

The optimiser will be to replace an existing standard timer clock that
is separate from the boiler.

Most of the optimisers that I have come across are either too complex
or expensive.

Graham

wrote:

I was looking for a very simple optimiser "timer" control panel that
can be fitted to a domestic gas powered central heating system.

It is a combi - instant hot water boiler.

The optimiser will be to replace an existing standard timer clock that
is separate from the boiler.

Most of the optimisers that I have come across are either too complex
or expensive.

What do you mean by 'optimiser', and what have you looked at?
What I recall was gizmos sold many many years ago to prevent (or reduce)
boiler cycling, but this shouldn't occur with a properly designed system to
current standards.

On Wed, 16 Nov 2005 23:25:45 GMT, wrote:


What do you mean by 'optimiser', and what have you looked at?
What I recall was gizmos sold many many years ago to prevent (or reduce)
boiler cycling, but this shouldn't occur with a properly designed system to
current standards.

It has an internal and an external heat sensor.

You set the optimiser to reach a particular temp within the property.

You then set the timer. The system will then calculate (based on the
temperature sensors) when the boiler needs to switch on and off.

The whole idea is that if you set the optimiser from, say, 6.00am to
8.00am that the house will be up to the correct temperature (allowing
for local fluctuations within the house) at 6.00am.

On a warm morning the boiler might switch on at 5.30am to achieve
this. On a very cold morning the boiler might have to switch on at
5.00am to achieve this.

Similarly, if it is warm outside but initially cold in the house the
boiler might be able to switch off the cycle completely at 7.30am.
However, if it is still very cold outside it might wait until 8.00am.

We have an optimiser system fitted at work.

It means that you save gas and you know that the property will always
be at the correct temp during the precise periods that you want the
heating.

Graham

wrote in message
news
I was looking for a very simple optimiser "timer" control panel that
can be fitted to a domestic gas powered central heating system.

It is a combi - instant hot water boiler.

The optimiser will be to replace an existing standard timer clock that
is separate from the boiler.

Most of the optimisers that I have come across are either too complex
or expensive.

Honeywell CM67 with the optimisation function is what you need.

Doctor Drivel wrote:

Honeywell CM67 with the optimisation function is what you need.

IMVHO I still debate there is any _significant_ benefit of having
"optimum start" on a prog.stat, as the boiler burn time is going to be
the same and the differernce between the heat being on(or off) for an
extra 20 or 30 minutes isn't going to make much difference to the fuel
savings, and the "heat leakage" of a relatively well insulated and
draught free house isn't going to be the same as a 1970's commercial
premisis (or whatever)

Just my take on it. FWIW

Weather compensation that adjusts the CH water temp depending on outside
temp is great though.

--
http://gymratz.co.uk - Best Gym Equipment & Bodybuilding Supplements UK.
http://trade-price-supplements.co.uk - TRADE PRICED SUPPLEMENTS for ALL!
http://fitness-equipment-uk.com - UK's No.1 Fitness Equipment Suppliers.
http://gymratz.co.uk/hot-seat.htm - Live web-cam! (sometimes)

"Pet @ www.gymratz.co.uk ;?)" wrote:
Doctor Drivel wrote:

Honeywell CM67 with the optimisation function is what you need.

IMVHO I still debate there is any _significant_ benefit of having
"optimum start" on a prog.stat, as the boiler burn time is going to be
the same and the differernce between the heat being on(or off) for an
extra 20 or 30 minutes isn't going to make much difference to the fuel
savings, and the "heat leakage" of a relatively well insulated and
draught free house isn't going to be the same as a 1970's commercial
premisis (or whatever)

Just my take on it. FWIW


At the moment my boiler is on about 6 hours of the day so a saving of 20-30
minutes a day is quite significant.

Rob

"Rob Summers" wrote in message
...
"Pet @ www.gymratz.co.uk ;?)" wrote:
Doctor Drivel wrote:

Honeywell CM67 with the optimisation function is what you need.

IMVHO I still debate there is any _significant_ benefit of having
"optimum start" on a prog.stat,

Totally and utterly wrong. Some Optimise on and off across all time zones
selected. These really drop the fuel bills.

At the moment my boiler is on about 6 hours of the day so a saving of
20-30
minutes a day is quite significant.

Over year it is. If it takes 45 minutes to heat your house from cold it
could hold it off for 45 minutes. Those that optimise off, and on and off
through the time zones you programme, are superb. Not cheap though.

Rob Summers wrote:

At the moment my boiler is on about 6 hours of the day so a saving of 20-30
minutes a day is quite significant.

I don't think it is quite as simple as that.

Let's say your boiler comes on 30 minutes earlier than it might need to
were it controlled by "optimum start" that 30 minutes of heat is not
just 30 minutes of "wasted" energy, it is energy being stored within the
fabric of the building, so, come the 6th hour of the day, the
thermostat(s) will have kicked the boiler off for much longer
(throughout the day)thanks to the pre-heated walls etc therby regaining
a very significant percentage of the initial additional "on" period.

Regardless of how long it is on for, the actual wasted energy is the
energy "leakage" from the building which would be down to poor
insulation and draughts, so a well insulated and draught free property
wouldn't just "lose" 30 minutes of burned fuel.

Hence, to re-coup however many hundreds of pounds the complex controll
hardware costs may take an exceptioanlly long time.
Better off putting the money into additional insulation, argon filled
triple glazed windows, heat recovery thingys etc.

(I'm sounding like DrEvil now!)

That's what I think anyway.

:¬)


--
http://gymratz.co.uk - Best Gym Equipment & Bodybuilding Supplements UK.
http://trade-price-supplements.co.uk - TRADE PRICED SUPPLEMENTS for ALL!
http://fitness-equipment-uk.com - UK's No.1 Fitness Equipment Suppliers.
http://gymratz.co.uk/hot-seat.htm - Live web-cam! (sometimes)

"Pet @ www.gymratz.co.uk ;¬)" wrote in message
. uk...
Rob Summers wrote:

At the moment my boiler is on about 6 hours of the day so a saving of
20-30
minutes a day is quite significant.

I don't think it is quite as simple as that.

Let's say your boiler comes on 30 minutes earlier than it might need to
were it controlled by "optimum start" that 30 minutes of heat is not
just 30 minutes of "wasted" energy, it is energy being stored within the
fabric of the building, so, come the 6th hour of the day, the
thermostat(s) will have kicked the boiler off for much longer
(throughout the day)thanks to the pre-heated walls etc therby regaining
a very significant percentage of the initial additional "on" period.

Regardless of how long it is on for, the actual wasted energy is the
energy "leakage" from the building which would be down to poor
insulation and draughts, so a well insulated and draught free property
wouldn't just "lose" 30 minutes of burned fuel.

Hence, to re-coup however many hundreds of pounds the complex controll
hardware costs may take an exceptioanlly long time.
Better off putting the money into additional insulation, argon filled
triple glazed windows, heat recovery thingys etc.

(I'm sounding like DrEvil now!)

That's what I think anyway.

A very good post, and very sensible, except that a Honeywell CM67 is only a
few extra pounds for the optimisation function.

Doctor Drivel wrote:

Totally and utterly wrong. Some Optimise on and off across all time zones
selected. These really drop the fuel bills.

Read my earlier reply.

I am very suprised that you consider ther may be significant savings.
Sou you say you want the evening temp to be held at 21 degrees untill
22:00 perhaps.
how does an "optimised off" (if it even exists) prog stat make any
difference over any ordinary room stat/timer combination?



Over year it is. If it takes 45 minutes to heat your house from cold it
could hold it off for 45 minutes. Those that optimise off, and on and off
through the time zones you programme, are superb. Not cheap though.

Well, I suppose if you were just pumping energy into an over ventilated
un-insulated building then sure, 30 minutes of not heating the outside
world would prove usefull, however if correctly insulated, heat loss
would be minimal.

Accurately controlling on/off times of a boiler is nothing compared to
corect insulation. If there are "significant" savings to be made by
saving 30 or 60 minutes "boiler on" time then I would suggest a vast
amount more would be saved by bringing insulation levels up to or beyond
recommended spec.

But I'm sure you'll come back with another statement that re-writes the
basic laws of physics.

--
http://gymratz.co.uk - Best Gym Equipment & Bodybuilding Supplements UK.
http://trade-price-supplements.co.uk - TRADE PRICED SUPPLEMENTS for ALL!
http://fitness-equipment-uk.com - UK's No.1 Fitness Equipment Suppliers.
http://gymratz.co.uk/hot-seat.htm - Live web-cam! (sometimes)

Doctor Drivel wrote:

A very good post, and very sensible, except that a Honeywell CM67 is only a
few extra pounds for the optimisation function.

But it's really ugly, and only has optimised start (first burn) IIRC
which goes back to my point of being more of a gadget than anything else.

--
http://gymratz.co.uk - Best Gym Equipment & Bodybuilding Supplements UK.
http://trade-price-supplements.co.uk - TRADE PRICED SUPPLEMENTS for ALL!
http://fitness-equipment-uk.com - UK's No.1 Fitness Equipment Suppliers.
http://gymratz.co.uk/hot-seat.htm - Live web-cam! (sometimes)

"Pet @ www.gymratz.co.uk ;¬)" wrote in message
. uk...
Doctor Drivel wrote:

Totally and utterly wrong. Some Optimise on and off across all time
zones
selected. These really drop the fuel bills.

Read my earlier reply.

I am very suprised that you consider ther may be significant savings.
Sou you say you want the evening temp to be held at 21 degrees untill
22:00 perhaps.
how does an "optimised off" (if it even exists) prog stat make any
difference over any ordinary room stat/timer combination?

It optimises off as it optimises on. It has an end time and calculates the
heat required to keep the system up to temp before the end time target. The
better systems "learn" the heating system.

Over year it is. If it takes 45 minutes to heat your house from cold
it
could hold it off for 45 minutes. Those that optimise off, and on and
off
through the time zones you programme, are superb. Not cheap though.

Well, I suppose if you were just pumping energy into an over ventilated
un-insulated building then sure, 30 minutes of not heating the outside
world would prove usefull, however if correctly insulated, heat loss
would be minimal.

The point is not insulation. It is whether optimisation saves energy. In a
superinsulated air-tight house its effect would be minimum compared to
normal British crap house.

snip off topic stuff

But I'm sure you'll come back with
another statement that re-writes the
basic laws of physics.

You are confused..and it's not even Friday.

"Pet @ www.gymratz.co.uk ;¬)" wrote in message
. uk...
Doctor Drivel wrote:

A very good post, and very sensible, except that a Honeywell CM67 is
only a
few extra pounds for the optimisation function.

But it's really ugly,

Then buy a Landis & Staefa. Which I think is better.

and only has optimised start (first burn) IIRC
which goes back to my point of being more of a gadget than anything else.

The DCD optimises off and on on all time segments
http://members.aol.com/dcdcontrol/indexctr.htm

BRE tested it and on a typical British system saved 25% of fuel.

On Thu, 17 Nov 2005 08:48:54 +0000, graham wrote:

On Wed, 16 Nov 2005 23:25:45 GMT, wrote:


What do you mean by 'optimiser', and what have you looked at?
What I recall was gizmos sold many many years ago to prevent (or reduce)
boiler cycling, but this shouldn't occur with a properly designed system to
current standards.

It has an internal and an external heat sensor.

You set the optimiser to reach a particular temp within the property.

You then set the timer. The system will then calculate (based on the
temperature sensors) when the boiler needs to switch on and off.

The whole idea is that if you set the optimiser from, say, 6.00am to
8.00am that the house will be up to the correct temperature (allowing
for local fluctuations within the house) at 6.00am.

On a warm morning the boiler might switch on at 5.30am to achieve
this. On a very cold morning the boiler might have to switch on at
5.00am to achieve this.

Similarly, if it is warm outside but initially cold in the house the
boiler might be able to switch off the cycle completely at 7.30am.
However, if it is still very cold outside it might wait until 8.00am.

We have an optimiser system fitted at work.

It means that you save gas and you know that the property will always
be at the correct temp during the precise periods that you want the
heating.

If you want this level of sophistication cost and complexity are part of
the territory. Opinions vary on this matter including the opinion of
people I respect greatly.
Costs of the Honeywell CM67 seem to be around £75 and people who have
them seem happy that they are programmable with a reasonable ease relative
to the complexity.

IMHO a simple programmable thermostat is about £30. Since the
night time temperature will be maintained (at say 15C) the system only has
to heat the house by a certain maximum amount in the morning.


--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html

"Ed Sirett" wrote in message
news
On Thu, 17 Nov 2005 08:48:54 +0000, graham wrote:

On Wed, 16 Nov 2005 23:25:45 GMT, wrote:


What do you mean by 'optimiser', and what have you looked at?
What I recall was gizmos sold many many years ago to prevent (or reduce)
boiler cycling, but this shouldn't occur with a properly designed system
to
current standards.

It has an internal and an external heat sensor.

You set the optimiser to reach a particular temp within the property.

You then set the timer. The system will then calculate (based on the
temperature sensors) when the boiler needs to switch on and off.

The whole idea is that if you set the optimiser from, say, 6.00am to
8.00am that the house will be up to the correct temperature (allowing
for local fluctuations within the house) at 6.00am.

On a warm morning the boiler might switch on at 5.30am to achieve
this. On a very cold morning the boiler might have to switch on at
5.00am to achieve this.

Similarly, if it is warm outside but initially cold in the house the
boiler might be able to switch off the cycle completely at 7.30am.
However, if it is still very cold outside it might wait until 8.00am.

We have an optimiser system fitted at work.

It means that you save gas and you know that the property will always
be at the correct temp during the precise periods that you want the
heating.

If you want this level of sophistication cost and complexity are part of
the territory. Opinions vary on this matter including the opinion of
people I respect greatly.
Costs of the Honeywell CM67 seem to be around £75

More like £50

and people who have
them seem happy that they are programmable with a reasonable ease relative
to the complexity.

IMHO a simple programmable thermostat is about £30. Since the
night time temperature will be maintained (at say 15C) the system only has
to heat the house by a certain maximum amount in the morning.

You opinion is lacking then. For £20 more you get far more, far more. Well
worth it all around.

On Thu, 17 Nov 2005 19:39:20 +0000, Doctor Drivel wrote:


"Ed Sirett" wrote in message
news
On Thu, 17 Nov 2005 08:48:54 +0000, graham wrote:

On Wed, 16 Nov 2005 23:25:45 GMT, wrote:


What do you mean by 'optimiser', and what have you looked at?
What I recall was gizmos sold many many years ago to prevent (or reduce)
boiler cycling, but this shouldn't occur with a properly designed system
to
current standards.

It has an internal and an external heat sensor.

You set the optimiser to reach a particular temp within the property.

You then set the timer. The system will then calculate (based on the
temperature sensors) when the boiler needs to switch on and off.

The whole idea is that if you set the optimiser from, say, 6.00am to
8.00am that the house will be up to the correct temperature (allowing
for local fluctuations within the house) at 6.00am.

On a warm morning the boiler might switch on at 5.30am to achieve
this. On a very cold morning the boiler might have to switch on at
5.00am to achieve this.

Similarly, if it is warm outside but initially cold in the house the
boiler might be able to switch off the cycle completely at 7.30am.
However, if it is still very cold outside it might wait until 8.00am.

We have an optimiser system fitted at work.

It means that you save gas and you know that the property will always
be at the correct temp during the precise periods that you want the
heating.

If you want this level of sophistication cost and complexity are part of
the territory. Opinions vary on this matter including the opinion of
people I respect greatly.
Costs of the Honeywell CM67 seem to be around £75

More like £50

and people who have
them seem happy that they are programmable with a reasonable ease relative
to the complexity.

IMHO a simple programmable thermostat is about £30. Since the
night time temperature will be maintained (at say 15C) the system only has
to heat the house by a certain maximum amount in the morning.

You opinion is lacking then. For £20 more you get far more, far more. Well
worth it all around.

(I don't believe that) You are in the position that you have to
_explain_ the operation of the heating controls to purchasers.

Even the simplest programmable stat is much too complex for some people.

--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html

On Thu, 17 Nov 2005 17:58:11 GMT, Pet @ www.gymratz.co.uk ;ª) wrote:

Let's say your boiler comes on 30 minutes earlier than it might need
to were it controlled by "optimum start" that 30 minutes of heat is
not just 30 minutes of "wasted" energy, it is energy being stored
within the fabric of the building,

If a "box" requires 10kWHrs of heat input to maintain its temperature
getting it up to that temperature 30mins before it is required means
that 5kWhrs of heat are lost. Yes, the box structure will also warm up
but it is going to do that anyway, and release that heat later. That
is not relevant, as what ever you do there is always going to be a
10kWhr flow of heat from the box to the outside, laws of
thermodynamics that you can't change.

If you take the same box and reduce it's heat loss by insulation then
the amount of heat lost is also reduced but it is still lost. It is up
to people to decide if the savings from a complex control system or
those from better insulation are best. Personally I'd go for both.

--
Cheers
Dave. pam is missing e-mail

"Ed Sirett" wrote in message
news
On Thu, 17 Nov 2005 19:39:20 +0000, Doctor Drivel wrote:


"Ed Sirett" wrote in message
news
On Thu, 17 Nov 2005 08:48:54 +0000, graham wrote:

On Wed, 16 Nov 2005 23:25:45 GMT, wrote:


What do you mean by 'optimiser', and what have you looked at?
What I recall was gizmos sold many many years ago to prevent (or
reduce)
boiler cycling, but this shouldn't occur with a properly designed
system
to
current standards.

It has an internal and an external heat sensor.

You set the optimiser to reach a particular temp within the property.

You then set the timer. The system will then calculate (based on the
temperature sensors) when the boiler needs to switch on and off.

The whole idea is that if you set the optimiser from, say, 6.00am to
8.00am that the house will be up to the correct temperature (allowing
for local fluctuations within the house) at 6.00am.

On a warm morning the boiler might switch on at 5.30am to achieve
this. On a very cold morning the boiler might have to switch on at
5.00am to achieve this.

Similarly, if it is warm outside but initially cold in the house the
boiler might be able to switch off the cycle completely at 7.30am.
However, if it is still very cold outside it might wait until 8.00am.

We have an optimiser system fitted at work.

It means that you save gas and you know that the property will always
be at the correct temp during the precise periods that you want the
heating.

If you want this level of sophistication cost and complexity are part
of
the territory. Opinions vary on this matter including the opinion of
people I respect greatly.
Costs of the Honeywell CM67 seem to be around £75

More like £50

and people who have
them seem happy that they are programmable with a reasonable ease
relative
to the complexity.

IMHO a simple programmable thermostat is about £30. Since the
night time temperature will be maintained (at say 15C) the system only
has
to heat the house by a certain maximum amount in the morning.

You opinion is lacking then. For £20 more you get far more, far more.
Well
worth it all around.

(I don't believe that) You are in the position that you have to
_explain_ the operation of the heating controls to purchasers.

Even the simplest programmable stat is much too complex for some people.

This is easier as all you do is punch in the occupation times, leaving out
any warm up times.

In article , wrote:
But it's really ugly, and only has optimised start (first burn) IIRC
which goes back to my point of being more of a gadget than anything else.

I turned the optimising off on mine because it was cutting in far too soon.
Otherwise the CM67 is IMHO simply brilliant, especially being able to use
the Party button to hold the heating off for a hour or two if you are going
out.

--
Tony Bryer SDA UK 'Software to build on' http://www.sda.co.uk
Free SEDBUK boiler database browser http://www.sda.co.uk/qsedbuk.htm
[Latest version QSEDBUK 1.10 released 4 April 2005]

In article ews.net,
Doctor Drivel wrote:
The DCD optimises off and on on all time segments
http://members.aol.com/dcdcontrol/indexctr.htm

BRE tested it and on a typical British system saved 25% of fuel.

You can only save 25% by putting 25% less heat into a house. As the
average difference across the heating season between internal and
external temperatures is 10-12C this would translate to having your
house 2-3C colder than it presently is. All the stuff about overshoots
is junk science IMO: people set the thermostat to what they find
comfortable, not a number.

--
Tony Bryer SDA UK 'Software to build on' http://www.sda.co.uk
Free SEDBUK boiler database browser http://www.sda.co.uk/qsedbuk.htm
[Latest version QSEDBUK 1.10 released 4 April 2005]

"Tony Bryer" wrote in message
...
In article ews.net,
Doctor Drivel wrote:
The DCD optimises off and on on all time segments
http://members.aol.com/dcdcontrol/indexctr.htm

BRE tested it and on a typical British system saved 25% of fuel.

You can only save 25% by putting 25% less heat into a house. As the
average difference across the heating season between internal and
external temperatures is 10-12C this would translate to having your
house 2-3C colder than it presently is. All the stuff about overshoots
is junk science IMO: people set the thermostat to what they find
comfortable, not a number.

Take it up with BRE.

On Thu, 17 Nov 2005 23:16:20 +0000, Doctor Drivel wrote:


"Ed Sirett" wrote in message
news
On Thu, 17 Nov 2005 19:39:20 +0000, Doctor Drivel wrote:


"Ed Sirett" wrote in message
news On Thu, 17 Nov 2005 08:48:54 +0000, graham wrote:

On Wed, 16 Nov 2005 23:25:45 GMT, wrote:


What do you mean by 'optimiser', and what have you looked at?
What I recall was gizmos sold many many years ago to prevent (or
reduce)
boiler cycling, but this shouldn't occur with a properly designed
system
to
current standards.

It has an internal and an external heat sensor.

You set the optimiser to reach a particular temp within the property.

You then set the timer. The system will then calculate (based on the
temperature sensors) when the boiler needs to switch on and off.

The whole idea is that if you set the optimiser from, say, 6.00am to
8.00am that the house will be up to the correct temperature (allowing
for local fluctuations within the house) at 6.00am.

On a warm morning the boiler might switch on at 5.30am to achieve
this. On a very cold morning the boiler might have to switch on at
5.00am to achieve this.

Similarly, if it is warm outside but initially cold in the house the
boiler might be able to switch off the cycle completely at 7.30am.
However, if it is still very cold outside it might wait until 8.00am.

We have an optimiser system fitted at work.

It means that you save gas and you know that the property will always
be at the correct temp during the precise periods that you want the
heating.

If you want this level of sophistication cost and complexity are part
of
the territory. Opinions vary on this matter including the opinion of
people I respect greatly.
Costs of the Honeywell CM67 seem to be around £75

More like £50

and people who have
them seem happy that they are programmable with a reasonable ease
relative
to the complexity.

IMHO a simple programmable thermostat is about £30. Since the
night time temperature will be maintained (at say 15C) the system only
has
to heat the house by a certain maximum amount in the morning.

You opinion is lacking then. For £20 more you get far more, far more.
Well
worth it all around.

(I don't believe that) You are in the position that you have to
_explain_ the operation of the heating controls to purchasers.

Even the simplest programmable stat is much too complex for some people.

This is easier as all you do is punch in the occupation times, leaving out
any warm up times.

It is quite possible that someone of your superior experience and
professional standing might be a little blind to the fact that 'just
punching in the occupation times' is well beyond some customers. It
probably comes as a surprise to you that a wall thermostat and/or a
Danfoss-Randall 102 timer is the pinnacle of their abilities.


--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html

"Ed Sirett" wrote in message
news
On Thu, 17 Nov 2005 23:16:20 +0000, Doctor Drivel wrote:


"Ed Sirett" wrote in message
news
On Thu, 17 Nov 2005 19:39:20 +0000, Doctor Drivel wrote:


"Ed Sirett" wrote in message
news On Thu, 17 Nov 2005 08:48:54 +0000, graham wrote:

On Wed, 16 Nov 2005 23:25:45 GMT,
wrote:


What do you mean by 'optimiser', and what have you looked at?
What I recall was gizmos sold many many years ago to prevent (or
reduce)
boiler cycling, but this shouldn't occur with a properly designed
system
to
current standards.

It has an internal and an external heat sensor.

You set the optimiser to reach a particular temp within the
property.

You then set the timer. The system will then calculate (based on
the
temperature sensors) when the boiler needs to switch on and off.

The whole idea is that if you set the optimiser from, say, 6.00am
to
8.00am that the house will be up to the correct temperature
(allowing
for local fluctuations within the house) at 6.00am.

On a warm morning the boiler might switch on at 5.30am to achieve
this. On a very cold morning the boiler might have to switch on at
5.00am to achieve this.

Similarly, if it is warm outside but initially cold in the house
the
boiler might be able to switch off the cycle completely at 7.30am.
However, if it is still very cold outside it might wait until
8.00am.

We have an optimiser system fitted at work.

It means that you save gas and you know that the property will
always
be at the correct temp during the precise periods that you want
the
heating.

If you want this level of sophistication cost and complexity are
part
of
the territory. Opinions vary on this matter including the opinion of
people I respect greatly.
Costs of the Honeywell CM67 seem to be around £75

More like £50

and people who have
them seem happy that they are programmable with a reasonable ease
relative
to the complexity.

IMHO a simple programmable thermostat is about £30. Since the
night time temperature will be maintained (at say 15C) the system
only
has
to heat the house by a certain maximum amount in the morning.

You opinion is lacking then. For £20 more you get far more, far
more.
Well
worth it all around.

(I don't believe that) You are in the position that you have to
_explain_ the operation of the heating controls to purchasers.

Even the simplest programmable stat is much too complex for some
people.

This is easier as all you do is punch in the occupation times, leaving
out
any warm up times.

It is quite possible that someone of your superior experience and
professional standing might be a little blind to the fact that 'just
punching in the occupation times' is well beyond some customers. It
probably comes as a surprise to you that a wall thermostat and/or a
Danfoss-Randall 102 timer is the pinnacle of their abilities.

The CM67 is not that bad. They get used to it.

The message .uk
from Ed Sirett contains these words:

Even the simplest programmable stat is much too complex for some people.

Even the simplest stat is too complex for some people (who are reduced
to using it just as an on/off switch). :-)

I have a Danfoss TP75 downstairs and a Horstmann Centaurstat upstairs.
No doubt Dribble will be on shortly to tell me I have made a dreadful
mistake (or even 2).
--
Roger Chapman

"Roger" wrote in message
k...
The message .uk
from Ed Sirett contains these words:

Even the simplest programmable stat is much too complex for some people.

Even the simplest stat is too complex for some people (who are reduced
to using it just as an on/off switch). :-)

I have a Danfoss TP75 downstairs and a Horstmann Centaurstat upstairs.
No doubt Dribble will be on shortly to tell me I have made a dreadful
mistake (or even 2).

Roger, knowing you they are not appropriate.