Is there some setup of a wet central heating system that will let radiators
be warm most of the time, and not cycling between over-hot and over-cold, as
mine are now?



At present I have a 15years old gas fired non-modulating boiler with a
pumped, vented, system, controlled by a wall thermostat. The controls on
this system will not avoid radiators that are either on and far too hot, or
off.



Thus the radiators cycle between being much hotter than is needed for just
compensating for heat losses from the rooms, producing unpleasantly hot air
around the radiators, and then cycling to a period of being colder than they
need to be.



Is there any setup that would give me the necessary heat output but in a
more balanced way, so the radiators will be on for longer but at an
appropriately lower temperature, with the period in the cycle when the
radiators are off being correspondingly much reduced?



As the age of the boiler is such that it could well be replaced, what kind
of setup should I be considering?



Regards.

On Mon, 3 Jul 2006 17:32:47 +0100, Anode wrote
(in article ):

Is there some setup of a wet central heating system that will let radiators
be warm most of the time, and not cycling between over-hot and over-cold, as
mine are now?



At present I have a 15years old gas fired non-modulating boiler with a
pumped, vented, system, controlled by a wall thermostat. The controls on
this system will not avoid radiators that are either on and far too hot, or
off.



Thus the radiators cycle between being much hotter than is needed for just
compensating for heat losses from the rooms, producing unpleasantly hot air
around the radiators, and then cycling to a period of being colder than they
need to be.



Is there any setup that would give me the necessary heat output but in a
more balanced way, so the radiators will be on for longer but at an
appropriately lower temperature, with the period in the cycle when the
radiators are off being correspondingly much reduced?



As the age of the boiler is such that it could well be replaced, what kind
of setup should I be considering?



I have a MAN Micromat boiler. It has a number of features which achieve what
you are describing:

- Burner modulates from 3-30kW

- Pump modulates continuously from 20-100% of output

- External temperature sensor is used in calculation of heat requirement.

- Detection of flow and return temperatures.

The result of this is that during the period from autumn to spring, the
boiler runs almost continuously at low output with radiator flow temperatures
in the region of 40-45 degrees, getting hotter only when the outside
temperature falls to a point that more heat output is required.

This is a high quality German designed and manufactured product. A similar
range is made by Viessmann.

Expect to pay around £1500 for such a boiler.

On Mon, 3 Jul 2006 17:32:47 +0100 Anode wrote :
Is there any setup that would give me the necessary heat output but in a
more balanced way, so the radiators will be on for longer but at an
appropriately lower temperature, with the period in the cycle when the
radiators are off being correspondingly much reduced?

The magic word is compensator - either sensing load or weather and turning
the flow temp up or down as necessary. They are available as an optional
extra on a number of the better boilers.

--
Tony Bryer SDA UK 'Software to build on' http://www.sda.co.uk

"Andy Hall" wrote in message
...
On Mon, 3 Jul 2006 17:32:47 +0100, Anode wrote
(in article ):

Is there some setup of a wet central heating system that will let
radiators
be warm most of the time, and not cycling between over-hot and over-cold,
as
mine are now?






I have a MAN Micromat boiler. It has a number of features which achieve
what
you are describing:

- Burner modulates from 3-30kW

- Pump modulates continuously from 20-100% of output

- External temperature sensor is used in calculation of heat requirement.

- Detection of flow and return temperatures.

The result of this is that during the period from autumn to spring, the
boiler runs almost continuously at low output with radiator flow
temperatures
in the region of 40-45 degrees, getting hotter only when the outside
temperature falls to a point that more heat output is required.

This is a high quality German designed and manufactured product. A
similar
range is made by Viessmann.

Expect to pay around £1500 for such a boiler.


Thank you for the information about the MAN Micromat, and the warning about
the price.

I shall get some details.

Regards, Anode.

"Tony Bryer" wrote in message
...
On Mon, 3 Jul 2006 17:32:47 +0100 Anode wrote :
Is there any setup that would give me the necessary heat output but in a
more balanced way, so the radiators will be on for longer but at an
appropriately lower temperature, with the period in the cycle when the
radiators are off being correspondingly much reduced?

The magic word is compensator - either sensing load or weather and turning
the flow temp up or down as necessary. They are available as an optional
extra on a number of the better boilers.

--
Tony Bryer SDA UK 'Software to build on' http://www.sda.co.uk

Thank you Tony. Your magic word has been duly noted.

Regards. Anode.

On Mon, 3 Jul 2006 17:59:36 +0100, Tony Bryer wrote
(in article ):

On Mon, 3 Jul 2006 17:32:47 +0100 Anode wrote :
Is there any setup that would give me the necessary heat output but in a
more balanced way, so the radiators will be on for longer but at an
appropriately lower temperature, with the period in the cycle when the
radiators are off being correspondingly much reduced?

The magic word is compensator - either sensing load or weather and turning
the flow temp up or down as necessary. They are available as an optional
extra on a number of the better boilers.



True...

Not to be confused with external boiler management boxes which use an
external temperature sensor. These are alleged to make some improvement in
terms of energy use in that they provide the heating system with "advanced
knowledge" of changes in outside temperature, but they drive the boiler on
and off to do so which doesn't really address the initial requirement.

"Andy Hall" aka Matt wrote in message
...
On Mon, 3 Jul 2006 17:59:36 +0100, Tony Bryer wrote
(in article ):

On Mon, 3 Jul 2006 17:32:47 +0100 Anode wrote :
Is there any setup that would give me the necessary heat output but in a
more balanced way, so the radiators will be on for longer but at an
appropriately lower temperature, with the period in the cycle when the
radiators are off being correspondingly much reduced?

The magic word is compensator - either
sensing load or weather and turning
the flow temp up or down as necessary.
They are available as an optional
extra on a number of the better boilers.

True...

Not to be confused with external boiler
management boxes which use an
external temperature sensor.
These are alleged to make some improvement in
terms of energy use in that they provide
the heating system with "advanced
knowledge" of changes in outside temperature,
but they drive the boiler on
and off to do so which doesn't really address
the initial requirement.

Matt, what ********. It does address the intial requirement in that the
rads are at the ideal temperature dictated by outside weather conditions.
Sirry irriot. It does this by switching the burner using electronic
anti-cycle control. Sirry irriot.

"Anode" wrote in message
...

"Andy Hall" wrote in message
...
On Mon, 3 Jul 2006 17:32:47 +0100, Anode wrote
(in article ):

Is there some setup of a wet central heating system that will let
radiators
be warm most of the time, and not cycling between over-hot and
over-cold, as
mine are now?






I have a MAN Micromat boiler. It has a number of features which achieve
what
you are describing:

- Burner modulates from 3-30kW

- Pump modulates continuously from 20-100% of output

- External temperature sensor is used in calculation of heat requirement.

- Detection of flow and return temperatures.

The result of this is that during the period from autumn to spring, the
boiler runs almost continuously at low output with radiator flow
temperatures
in the region of 40-45 degrees, getting hotter only when the outside
temperature falls to a point that more heat output is required.

This is a high quality German designed and manufactured product. A
similar
range is made by Viessmann.

Expect to pay around £1500 for such a boiler.


Thank you for the information about the MAN Micromat, and the warning
about the price.

I shall get some details.

Regards, Anode.

http://www.eco-hometec.co.uk Same boiler.

On Mon, 3 Jul 2006 18:42:06 +0100, Doctor Drivel wrote
(in article ews.net):


"Andy Hall" aka Matt wrote in message
...
On Mon, 3 Jul 2006 17:59:36 +0100, Tony Bryer wrote
(in article ):

On Mon, 3 Jul 2006 17:32:47 +0100 Anode wrote :
Is there any setup that would give me the necessary heat output but in a
more balanced way, so the radiators will be on for longer but at an
appropriately lower temperature, with the period in the cycle when the
radiators are off being correspondingly much reduced?

The magic word is compensator - either
sensing load or weather and turning
the flow temp up or down as necessary.
They are available as an optional
extra on a number of the better boilers.

True...

Not to be confused with external boiler
management boxes which use an
external temperature sensor.
These are alleged to make some improvement in
terms of energy use in that they provide
the heating system with "advanced
knowledge" of changes in outside temperature,
but they drive the boiler on
and off to do so which doesn't really address
the initial requirement.

Matt, what ********. It does address the intial requirement in that the
rads are at the ideal temperature dictated by outside weather conditions.
Sirry irriot. It does this by switching the burner using electronic
anti-cycle control. Sirry irriot.


No. The radiator temperatures will cycle up and down as the burner is turned
on and off by the external controller.

The correct solution is to use something that is integral and analogue to the
main boiler controller.

"Anode" wrote in message
news
Is there some setup of a wet central heating system that will let
radiators be warm most of the time, and not cycling between over-hot and
over-cold, as mine are now?

At present I have a 15years old gas fired non-modulating boiler with a
pumped, vented, system, controlled by a wall thermostat. The controls on
this system will not avoid radiators that are either on and far too hot,
or off.

Thus the radiators cycle between being much hotter than is needed for just
compensating for heat losses from the rooms, producing unpleasantly hot
air around the radiators, and then cycling to a period of being colder
than they need to be.

Is there any setup that would give me the necessary heat output but in a
more balanced way, so the radiators will be on for longer but at an
appropriately lower temperature, with the period in the cycle when the
radiators are off being correspondingly much reduced?

As the age of the boiler is such that it could well be replaced, what kind
of setup should I be considering?

Get a heat bank (thermal store). Heated by a Glow Worm condensing boiler
(excellent and cheap enough. Rebadged Vaillants). The heat bank to have two
cylinder stats to eliminate boiler cycling. The boiler comes in on one long
efficient burn. The boiler only heats the cylidner in one continuous burn,
not the rads directly.

The CH circuit taken off the store with thermo rad valves on each rad, using
an auto variable speed Grundfoss Alpha pump. The CH circuit takes what heat
it needs from the store, so always a continuous on-tap store of hot water
with no heat fluctuations.

The heat bank heats incoming cold mains water instantly, so no need for
storage tanks. In the morning the rads are instantly hot as the heat in the
store of water is up to temp and pumped immediately around the rads. The
thermo rad valve take care of local room temperature control.

This gives you:

1. Instant high pressure DHW at the taps and shower.
2. Temperature control at each room.
3. Boiler operating at ideal conditions with the ideal flow through the
boiler.
4. Boiler lasts longer as controls do not constantly switch off and on.
5. Boiler is simpler and easy to fix when down.
6. Full electric backup of DHW "and" CH if electric immersion fitted in the
Heat Bank.
7. No cold water tanks.
8. No room stat.
9. No complex expensive electronic controls.
10. Instant CH when switched on in the morning having a store of on tap hot
water.
11. Local room temperature control.

In article ews.net,
Doctor Drivel wrote:
Matt, what ********. It does address the intial requirement in that the
rads are at the ideal temperature dictated by outside weather
conditions.

Perhaps you need to shut your windows, then, when the heating is on?

--
*Sleep with a photographer and watch things develop

Dave Plowman London SW
To e-mail, change noise into sound.

"Andy Hall" aka Matt wrote in message
...
On Mon, 3 Jul 2006 18:42:06 +0100, Doctor Drivel wrote
(in article ews.net):


"Andy Hall" aka Matt wrote in message
...
On Mon, 3 Jul 2006 17:59:36 +0100, Tony Bryer wrote
(in article ):

On Mon, 3 Jul 2006 17:32:47 +0100 Anode wrote :
Is there any setup that would give me the necessary heat output but in
a
more balanced way, so the radiators will be on for longer but at an
appropriately lower temperature, with the period in the cycle when the
radiators are off being correspondingly much reduced?

The magic word is compensator - either
sensing load or weather and turning
the flow temp up or down as necessary.
They are available as an optional
extra on a number of the better boilers.

True...

Not to be confused with external boiler
management boxes which use an
external temperature sensor.
These are alleged to make some improvement in
terms of energy use in that they provide
the heating system with "advanced
knowledge" of changes in outside temperature,
but they drive the boiler on
and off to do so which doesn't really address
the initial requirement.

Matt, what ********. It does address the intial requirement in that the
rads are at the ideal temperature dictated by outside weather conditions.
Sirry irriot. It does this by switching the burner using electronic
anti-cycle control. Sirry irriot.


No. The radiator temperatures will cycle
up and down as the burner is turned
on and off by the external controller.

Within the range dictated to by the controller.

The correct solution is to use
something that is integral and analogue to the
main boiler controller.

Matt, a heat bank with a Grundfoss Alpha is the way. A continuous supply of
on-tap water for the CH. If the house only needs 1.5Kw of heat, the CH
circuit via the auto modulating pump, just takes the heat from the heat bank
store it wants. If it needs 0.5kW for the CH it takes it and boiler
cycling. No cycling or modulating of burners. Simple, easy, efficient.

On Mon, 3 Jul 2006 19:09:24 +0100, Doctor Drivel wrote
(in article ews.net):


"Andy Hall" aka Matt wrote in message
...
On Mon, 3 Jul 2006 18:42:06 +0100, Doctor Drivel wrote
(in article ews.net):


"Andy Hall" aka Matt wrote in message
...
On Mon, 3 Jul 2006 17:59:36 +0100, Tony Bryer wrote
(in article ):

On Mon, 3 Jul 2006 17:32:47 +0100 Anode wrote :
Is there any setup that would give me the necessary heat output but in
a
more balanced way, so the radiators will be on for longer but at an
appropriately lower temperature, with the period in the cycle when the
radiators are off being correspondingly much reduced?

The magic word is compensator - either
sensing load or weather and turning
the flow temp up or down as necessary.
They are available as an optional
extra on a number of the better boilers.

True...

Not to be confused with external boiler
management boxes which use an
external temperature sensor.
These are alleged to make some improvement in
terms of energy use in that they provide
the heating system with "advanced
knowledge" of changes in outside temperature,
but they drive the boiler on
and off to do so which doesn't really address
the initial requirement.

Matt, what ********. It does address the intial requirement in that the
rads are at the ideal temperature dictated by outside weather conditions.
Sirry irriot. It does this by switching the burner using electronic
anti-cycle control. Sirry irriot.


No. The radiator temperatures will cycle
up and down as the burner is turned
on and off by the external controller.

Within the range dictated to by the controller.

Which means that the boiler would need to cycle rapidly to achieve it or that
there would need to be a wide range of operating temperature. The first is
inefficient and the second is not what is wanted.




The correct solution is to use
something that is integral and analogue to the
main boiler controller.

Matt, a heat bank with a Grundfoss Alpha is the way. A continuous supply of
on-tap water for the CH. If the house only needs 1.5Kw of heat, the CH
circuit via the auto modulating pump, just takes the heat from the heat bank
store it wants. If it needs 0.5kW for the CH it takes it and boiler
cycling. No cycling or modulating of burners. Simple, easy, efficient.


This is unnecessarily complicated and expensive. If the heatbank is
maintained at a temperature worthwhile for HW production (80 degrees or so),
the effect will still be one of hot radiators but with a large temperature
differential as the TRVs operate reducing the flow.

It's far better, easier, more reliable and less expensive in terms of
solution cost to use a suitable boiler suitable for the requirement in the
first place.

Anode wrote:
Is there some setup of a wet central heating system that will let radiators
be warm most of the time, and not cycling between over-hot and over-cold, as
mine are now?

At present I have a 15years old gas fired non-modulating boiler with a
pumped, vented, system, controlled by a wall thermostat. The controls on
this system will not avoid radiators that are either on and far too hot, or
off.

Thus the radiators cycle between being much hotter than is needed for just
compensating for heat losses from the rooms, producing unpleasantly hot air
around the radiators, and then cycling to a period of being colder than they
need to be.

Is there any setup that would give me the necessary heat output but in a
more balanced way, so the radiators will be on for longer but at an
appropriately lower temperature, with the period in the cycle when the
radiators are off being correspondingly much reduced?

As the age of the boiler is such that it could well be replaced, what kind
of setup should I be considering?

http://www.pmengineer.com/CDA/Archiv...0000f932a8c0__

Search for other articles on that site by the same author. A modulating
boiler would be the simplest way of achieving what you're after, given
that your boiler may be due for replacement anyway.

The technology exists, but it is little used in the UK bacause our
heating technicians and/or CORGI technicians are mostly clueless about
it.

I have a non-condensing non-modulating boiler. This set-up lends itself
to the use of a thermal store (100 or 150 litres of stored water) so
that the boiler will run for some time in raising the temperature of
the stored water from,say, 60 to 82 degC. If you only had the water in
the system's pipes and radiators, the boiler would rapidly cycle on &
off under part-load conditions , e.g., a 17 kW on/off boiler but the
system only requires 2 or 3 kW of heat.

The flow to the heating system is through a 3-port mixing valve which
modulates around to achieve the required flow rate. The heating
(secondary) pump is downstream of the mixing valve, with a thermistor
temperature sensor downstream of that.

You need to control the return temperature on a non-condensing boiler
because a temperature of 60 degC would corrode the boiler. My set-up
limits the opening of the valve whilst Tr 60 degC, but this only
happens during warm-up from cold.

I got this system working mid-way through 2004/05 winter. Well worth
it. The heating is on all the time. The radiators are usually warm to
hot; you can usually keep your hand on them without needing hospital
treatment. However it can, and does, wind up to the 82 degC full Monty
during cold weather or during warm-up from cold. Heat up is spread over
about 10 minutes and you don't get the usual clicking & tapping of pipe
expansion when the timer or thermostat starts the heating.

Room temperatures are (and this is the important bit) right; not too
cold and never too hot. TRVs on all, but one, radiator. No problems
with TRV whistling noises, because of the modulating flow temperature.
I'd thought I may need a variable speed pump if this was a problem, but
I needn't bother. Disadvantages, it takes up a lot of space relative to
a wall-hung boiler, so not practical if space is tight. Mixing valves &
controllers are expensive.

There was a significant drop in gas consumption, but other energy
conservation work was also going on, so I can't estimate how much was
due to the heating amendments alone

I recently made enquiries about prices for a modulating condensing
Vaillant boiler for someone else. This boiler had an optional extra
electronic gadget & outdoor sensor to malke it a weather compensated
system. When I asked about the price of that gizmo, the man commented
that he'd never sold one before. I was also told by Vaillant that the
flow temperature is set by the outdoor temperature and it doesn't have
the facility to boost this temperature to warm-up from cold. this can
be a problem with basic systems (which is why I asked) .

..

Aidan wrote:

Link won't work; try this;

http://www.pmengineer.com/CDA/Archiv...00f932a8c0____

At present I have a 15years old gas fired non-modulating boiler with a
pumped, vented, system, controlled by a wall thermostat.

Mmm, that thermostat is a conventional electro-mechanical affair is it?

Has it got a neutral connection to it?

No neutral equals no return for the pre-heater

Result:- thermostat still works but with excessive hysteresis.

--
Graham


%Profound_observation%






Inviato da X-Privat.Org - Registrazione gratuita http://www.x-privat.org/join.php

"Andy Hall" aka Matt wrote in message
...

Matt, a heat bank with a Grundfoss Alpha is the way. A continuous supply
of
on-tap water for the CH. If the house only needs 1.5Kw of heat, the CH
circuit via the auto modulating pump, just takes the heat from the heat
bank
store it wants. If it needs 0.5kW for the CH it takes it and boiler
cycling. No cycling or modulating of burners. Simple, easy, efficient.


This is unnecessarily complicated and expensive.

Matt, I know you are not very good at this sort of thing, but I said
"Simple, easy, efficient."

There you go.

snip misinformed babble

"Dave Plowman (News)" through haze of senile
flatulence wrote in message ...
In article ews.net,
Doctor Drivel wrote:

Matt, what ********. It does address the intial requirement in that the
rads are at the ideal temperature dictated by outside weather
conditions.

Perhaps

snip senile babble

Sad I know.

"Aidan" wrote in message
oups.com...

Anode wrote:
Is there some setup of a wet central heating system that will let
radiators
be warm most of the time, and not cycling between over-hot and over-cold,
as
mine are now?

At present I have a 15years old gas fired non-modulating boiler with a
pumped, vented, system, controlled by a wall thermostat. The controls on
this system will not avoid radiators that are either on and far too hot,
or
off.

Thus the radiators cycle between being much hotter than is needed for
just
compensating for heat losses from the rooms, producing unpleasantly hot
air
around the radiators, and then cycling to a period of being colder than
they
need to be.

Is there any setup that would give me the necessary heat output but in a
more balanced way, so the radiators will be on for longer but at an
appropriately lower temperature, with the period in the cycle when the
radiators are off being correspondingly much reduced?

As the age of the boiler is such that it could well be replaced, what
kind
of setup should I be considering?

http://www.pmengineer.com/CDA/Archiv...0000f932a8c0__

Search for other articles on that site by the same author. A modulating
boiler would be the simplest way of achieving what you're after, given
that your boiler may be due for replacement anyway.

The technology exists, but it is little used in the UK bacause our
heating technicians and/or CORGI technicians are mostly clueless about
it.

I have a non-condensing non-modulating boiler. This set-up lends itself
to the use of a thermal store (100 or 150 litres of stored water) so
that the boiler will run for some time in raising the temperature of
the stored water from,say, 60 to 82 degC. If you only had the water in
the system's pipes and radiators, the boiler would rapidly cycle on &
off under part-load conditions , e.g., a 17 kW on/off boiler but the
system only requires 2 or 3 kW of heat.

The flow to the heating system is through a 3-port mixing valve which
modulates around to achieve the required flow rate.

Do you mean to the CH circuit or thermal store?

The heating
(secondary) pump is downstream of the mixing valve, with a thermistor
temperature sensor downstream of that.

You need to control the return temperature on a non-condensing boiler
because a temperature of 60 degC would corrode the boiler. My set-up
limits the opening of the valve whilst Tr 60 degC, but this only
happens during warm-up from cold.

I got this system working mid-way through 2004/05 winter. Well worth
it. The heating is on all the time. The radiators are usually warm to
hot; you can usually keep your hand on them without needing hospital
treatment. However it can, and does, wind up to the 82 degC full Monty
during cold weather or during warm-up from cold. Heat up is spread over
about 10 minutes and you don't get the usual clicking & tapping of pipe
expansion when the timer or thermostat starts the heating.

Room temperatures are (and this is the important bit) right; not too
cold and never too hot. TRVs on all, but one, radiator.

You can have them on all using a thermal store and a auto vraibel Grundfoss
Alpha pump, and not room stats. I would change the system to this setup.
Far better.

No problems
with TRV whistling noises, because of the modulating flow temperature.
I'd thought I may need a variable speed pump if this was a problem, but
I needn't bother. Disadvantages, it takes up a lot of space relative to
a wall-hung boiler, so not practical if space is tight. Mixing valves &
controllers are expensive.

Do you mean the tyhermal store is bulky.

There was a significant drop in gas consumption, but other energy
conservation work was also going on, so I can't estimate how much was
due to the heating amendments alone

I recently made enquiries about prices for a modulating condensing
Vaillant boiler for someone else. This boiler had an optional extra
electronic gadget & outdoor sensor to malke it a weather compensated
system. When I asked about the price of that gizmo, the man commented
that he'd never sold one before. I was also told by Vaillant that the
flow temperature is set by the outdoor temperature and it doesn't have
the facility to boost this temperature to warm-up from cold. this can
be a problem with basic systems (which is why I asked) .

That is a problem. The heat bank/thermal store is the best way.

"Andy Hall" aka Matt wrote in message
...
On Mon, 3 Jul 2006 19:04:06 +0100, Doctor Drivel wrote
(in article ews.net):


"Anode" wrote in message
news
Is there some setup of a wet central heating system that will let
radiators be warm most of the time, and not cycling between over-hot and
over-cold, as mine are now?

At present I have a 15years old gas fired non-modulating boiler with a
pumped, vented, system, controlled by a wall thermostat. The controls on
this system will not avoid radiators that are either on and far too hot,
or off.

Thus the radiators cycle between being much hotter than is needed for
just
compensating for heat losses from the rooms, producing unpleasantly hot
air around the radiators, and then cycling to a period of being colder
than they need to be.

Is there any setup that would give me the necessary heat output but in a
more balanced way, so the radiators will be on for longer but at an
appropriately lower temperature, with the period in the cycle when the
radiators are off being correspondingly much reduced?

As the age of the boiler is such that it could well be replaced, what
kind
of setup should I be considering?

Get a heat bank (thermal store). Heated by a Glow Worm condensing boiler
(excellent and cheap enough. Rebadged Vaillants). The heat bank to have
two
cylinder stats to eliminate boiler cycling.

Unnecessarily complicated.

snip misinformation by Matt

Matt, you know you know nothing about this sort of thing.

"Graham." wrote in message ...
At present I have a 15years old gas fired non-modulating boiler with a
pumped, vented, system, controlled by a wall thermostat.

Mmm, that thermostat is a conventional electro-mechanical affair is it?

Has it got a neutral connection to it?

No neutral equals no return for the pre-heater

Result:- thermostat still works but with excessive hysteresis.

--
Graham



Thermostat is Potterton PET 1.

Thermostat is Potterton PET 1.


That's OK.

My comments referred to the old fashioned bi-metal strip type.


Graham.

%Profound_observation%




Inviato da X-Privat.Org - Registrazione gratuita http://www.x-privat.org/join.php

On Mon, 3 Jul 2006 20:13:18 +0100, Doctor Drivel wrote
(in article ews.net):


"Andy Hall" aka Matt wrote in message
...

Matt, a heat bank with a Grundfoss Alpha is the way. A continuous supply
of
on-tap water for the CH. If the house only needs 1.5Kw of heat, the CH
circuit via the auto modulating pump, just takes the heat from the heat
bank
store it wants. If it needs 0.5kW for the CH it takes it and boiler
cycling. No cycling or modulating of burners. Simple, easy, efficient.


This is unnecessarily complicated and expensive.

Matt, I know you are not very good at this sort of thing, but I said
"Simple, easy, efficient."

There you go.

That might have more credibility if you really knew what it meant.

"Andy Hall" aka Matt wrote in message
...
On Mon, 3 Jul 2006 20:13:18 +0100, Doctor Drivel wrote
(in article ews.net):


"Andy Hall" aka Matt wrote in message
...

Matt, a heat bank with a Grundfoss Alpha is the way. A continuous
supply
of
on-tap water for the CH. If the house only needs 1.5Kw of heat, the CH
circuit via the auto modulating pump, just takes the heat from the heat
bank
store it wants. If it needs 0.5kW for the CH it takes it and boiler
cycling. No cycling or modulating of burners. Simple, easy, efficient.


This is unnecessarily complicated and expensive.

Matt, I know you are not very good at this sort of thing, but I said
"Simple, easy, efficient."

There you go.

That might have more credibility if you really knew what it meant.

Matt, I know you are not very good at this sort of thing, but I said
"Simple, easy, efficient."

Anode wrote:
Is there some setup of a wet central heating system that will let radiators
be warm most of the time, and not cycling between over-hot and over-cold, as
mine are now?



At present I have a 15years old gas fired non-modulating boiler with a
pumped, vented, system, controlled by a wall thermostat. The controls on
this system will not avoid radiators that are either on and far too hot, or
off.



Thus the radiators cycle between being much hotter than is needed for just
compensating for heat losses from the rooms, producing unpleasantly hot air
around the radiators, and then cycling to a period of being colder than they
need to be.



Is there any setup that would give me the necessary heat output but in a
more balanced way, so the radiators will be on for longer but at an
appropriately lower temperature, with the period in the cycle when the
radiators are off being correspondingly much reduced?



As the age of the boiler is such that it could well be replaced, what kind
of setup should I be considering?



Regards.












FIT TRV's

In article ,
Anode wrote:
At present I have a 15years old gas fired non-modulating boiler with a
pumped, vented, system, controlled by a wall thermostat. The controls on
this system will not avoid radiators that are either on and far too
hot, or off.

Surely in most cases it's the temperature of the room that matters?

Thus the radiators cycle between being much hotter than is needed for
just compensating for heat losses from the rooms, producing
unpleasantly hot air around the radiators, and then cycling to a period
of being colder than they need to be.

Are you forced to be that close to the rads? I've got one so close to this
computer I can touch it from the chair, but I'm not aware of heat actually
radiating from it - and certainly not hot air which rises.

That's not to say a modulating boiler isn't a good idea - I shall get one
when it comes time to change mine. But this will be for efficiency reasons
rather than comfort.

--
*Why is it that to stop Windows 95, you have to click on "Start"?

Dave Plowman London SW
To e-mail, change noise into sound.

Doctor Drivel wrote:

The flow to the heating system is through a 3-port mixing valve which
modulates around to achieve the required flow rate.

Do you mean to the CH circuit or thermal store?

From thermal store to CH circuit.
With burner off, the valve gradually opens as the store cools. With
burner on, the valve gradually closes as store heats up. Flow
temperature stays at set-point.

You can have them on all using a thermal store and a auto vraibel Grundfoss
Alpha pump, and not room stats. I would change the system to this setup.
Far better.

No. Hall has room temperature sensor, which has a function in varying
heating flow temperature . Outside also has an influence.

Do you mean the tyhermal store is bulky.
Store, boiler, pumps, controls, mixing valve.

"Dave Plowman (News)" through a haze of senile
flatulence wrote in message ...

Are you forced to be that close to the rads? I've got one so close to this
computer I can touch it from the chair, but I'm not aware of heat actually
radiating from it - and certainly not hot air which rises.

Richard Cranium, doe the warden allow you have a hot radiator on in this
weather?

In article ews.net,
Doctor Drivel wrote:
Richard Cranium, doe the warden allow you have a hot radiator on in this
weather?

Is doe the warden a relation of bob the builder? I think we should be told.

--
*Despite the cost of living, have you noticed how it remains so popular?*

Dave Plowman London SW
To e-mail, change noise into sound.

"Dave Plowman (News)" wrote in message
...
In article ,
Anode wrote:
At present I have a 15years old gas fired non-modulating boiler with a
pumped, vented, system, controlled by a wall thermostat. The controls on
this system will not avoid radiators that are either on and far too
hot, or off.

Surely in most cases it's the temperature of the room that matters?

Thus the radiators cycle between being much hotter than is needed for
just compensating for heat losses from the rooms, producing
unpleasantly hot air around the radiators, and then cycling to a period
of being colder than they need to be.

Are you forced to be that close to the rads? I've got one so close to this
computer I can touch it from the chair, but I'm not aware of heat actually
radiating from it - and certainly not hot air which rises.

That's not to say a modulating boiler isn't a good idea - I shall get one
when it comes time to change mine. But this will be for efficiency reasons
rather than comfort.

--

Dave Plowman


It could be just a personal thing, but radiators above a certain temperature
I find unpleasant and best avoided; it seems to be something to do with
breathing in the hot air from around them so I was trying to avoid this in
future alterations. I understand that comfort level is affected by many
factors, including relative humidity and radiant heat emission from walls
and objects in the room, so personal comfort can no doubt be a complex
concept.

Anode.

On Tue, 4 Jul 2006 00:08:06 +0100, Doctor Drivel wrote
(in article ews.net):


"Dave Plowman (News)" through a haze of senile
flatulence wrote in message ...

Are you forced to be that close to the rads? I've got one so close to this
computer I can touch it from the chair, but I'm not aware of heat actually
radiating from it - and certainly not hot air which rises.

Richard Cranium, doe the warden allow you have a hot radiator on in this
weather?


What are you rabbiting on about now...?

On Tue, 4 Jul 2006 01:01:43 +0100, Anode wrote
(in article ):


"Dave Plowman (News)" wrote in message
...
In article ,
Anode wrote:
At present I have a 15years old gas fired non-modulating boiler with a
pumped, vented, system, controlled by a wall thermostat. The controls on
this system will not avoid radiators that are either on and far too
hot, or off.

Surely in most cases it's the temperature of the room that matters?

Thus the radiators cycle between being much hotter than is needed for
just compensating for heat losses from the rooms, producing
unpleasantly hot air around the radiators, and then cycling to a period
of being colder than they need to be.

Are you forced to be that close to the rads? I've got one so close to this
computer I can touch it from the chair, but I'm not aware of heat actually
radiating from it - and certainly not hot air which rises.

That's not to say a modulating boiler isn't a good idea - I shall get one
when it comes time to change mine. But this will be for efficiency reasons
rather than comfort.

--

Dave Plowman


It could be just a personal thing, but radiators above a certain temperature
I find unpleasant and best avoided; it seems to be something to do with
breathing in the hot air from around them so I was trying to avoid this in
future alterations. I understand that comfort level is affected by many
factors, including relative humidity and radiant heat emission from walls
and objects in the room, so personal comfort can no doubt be a complex
concept.

Anode.



If that's your only issue rather than having a more or less constant
temperature, you could resolve it quite easily.

For conventional boilers, radiators are run at 82 degrees flow and 70 return.
Radiators are sized for the room heat loss requirement to work with this.

If you install a condensing boiler, it *can* work at these temperatures -
they do to avoid mandating radiator changes. However, it will operate more
effiiciently at lower temperatures, so it is more typical to design for 70
flow and 50 return. Heat output is then about 30% less so the radiators
have to be larger. There is no reason why you couldn't extend this
principle further, use even larger radiators and lower temperatures.

"Doctor Drivel" wrote in message
reenews.net...
On Mon, 3 Jul 2006 17:32:47 +0100 Anode wrote :
Is there any setup that would give me the necessary heat output but
in a
more balanced way, so the radiators will be on for longer but at an
appropriately lower temperature, with the period in the cycle when
the
radiators are off being correspondingly much reduced?


Matt, a heat bank with a Grundfoss Alpha is the way. A continuous supply
of on-tap water for the CH. If the house only needs 1.5Kw of heat, the CH
circuit via the auto modulating pump, just takes the heat from the heat
bank store it wants. If it needs 0.5kW for the CH it takes it and boiler
cycling. No cycling or modulating of burners. Simple, easy, efficient.


Thank you Drivel for your suggestion.

Anode.

Andy Hall wrote:

It could be just a personal thing, but radiators above a certain temperature
I find unpleasant and best avoided; it seems to be something to do with
breathing in the hot air from around them so I was trying to avoid this in
future alterations. I understand that comfort level is affected by many
factors, including relative humidity and radiant heat emission from walls
and objects in the room, so personal comfort can no doubt be a complex
concept.

Yes, ditto. I find continuously warm rads much preferable to
intermittently scorching rads.

The radiant heat losses to/from the surfaces in the room have a
significant effect on one's feeling of comfort. You can usually drop
the air temperature by a couple of degrees in a room with UFH because
the radiant component of the heat emission is much higher.

If that's your only issue rather than having a more or less constant
temperature, you could resolve it quite easily.

For conventional boilers, radiators are run at 82 degrees flow and 70 return.
Radiators are sized for the room heat loss requirement to work with this.

Whilst this is true, the radiators are sized for the worst-case,
mid-winter, design conditions,
-5 degC or suchlike outside, which probably occurs for only 2% or 5%
of the time that the heating is on.

For the other 95-98% of the time, partial load conditions, the
radiators could operate at less than the 'classic design' 82 flow 71
return, whilst still putting out sufficient heat to offset the heat
losses. Similarly, if the system can vary the flow temperature, they
can operate continuously at lower temperatures, rather than
intermittent bursts of 82/71.

I was surprised by the amount of time my modified modulating system
operates at less than 100%; probably 90% of the time and I didn't
change any radiators. You will achieve worthwhile savings with a
condensing modulating boilers even without changing radiators.


If you install a condensing boiler, it *can* work at these temperatures -
they do to avoid mandating radiator changes. However, it will operate more
effiiciently at lower temperatures, so it is more typical to design for 70
flow and 50 return. Heat output is then about 30% less so the radiators
have to be larger. There is no reason why you couldn't extend this
principle further, use even larger radiators and lower temperatures.

In the extreme, it heads towards underfloor heating, where the floors
are huge radiators operating at 29 degC surface temperature.

"Dave Plowman (News)" through a haze of senile
flatulence wrote in message ...
In article ews.net,
Doctor Drivel wrote:

Richard Cranium, does the warden allow
you have a hot radiator on in this
weather?

Is doe the warden a relation of bob the builder?

I wonder if the warden lets them watch Bob on DVD?

"Aidan" wrote in message
oups.com...

I was surprised by the amount of time
my modified modulating system
operates at less than 100%; probably
90% of the time and I didn't
change any radiators. You will achieve
worthwhile savings with a
condensing modulating boilers even
without changing radiators.

Only if it has the correct modulating control system. One that modulates on
load compensation rather than maintaining a flow temperature set point.
These boilers are not cheap.

A heat bank/thermal store using TRVs on all rads and an auto modulating pump
(Alpha) on the CH circuit , will slowly inject high temp water into the rads
when the TRVs throttle back. This high temp water then slowly mixes with the
cooler water in the rads. So you may have 70C water in the rad flow pipe,
but the rads are very much cooler. If the CH circuit demands 0.25kW of
heat, as a few TRV are just cracked open, it just takes it from the store as
everything, the CH pump and TRVs are modulating.

A condensing boiler mated to a heat bank/thermal store will be very
efficient. Using a store set to 70-75C and a blending valve on the boiler
flow/return to the store set to give a 22C to 25C drop of setpoint (say
50C), will be condensing the vast majority of the time. The valve also
maintains
stratification.

So, a simple, less complex, more reliable, condensing boiler can be used.

On Tue, 4 Jul 2006 14:03:55 +0100, Doctor Drivel wrote
(in article ews.net):


"Aidan" wrote in message
oups.com...

I was surprised by the amount of time
my modified modulating system
operates at less than 100%; probably
90% of the time and I didn't
change any radiators. You will achieve
worthwhile savings with a
condensing modulating boilers even
without changing radiators.

Only if it has the correct modulating control system. One that modulates on
load compensation rather than maintaining a flow temperature set point.
These boilers are not cheap.

In terms of total cost of ownership and the required results over the
operating life of the system, this is not significant.



A heat bank/thermal store using TRVs on all rads and an auto modulating pump
(Alpha) on the CH circuit , will slowly inject high temp water into the rads
when the TRVs throttle back. This high temp water then slowly mixes with the
cooler water in the rads. So you may have 70C water in the rad flow pipe,
but the rads are very much cooler. If the CH circuit demands 0.25kW of
heat, as a few TRV are just cracked open, it just takes it from the store as
everything, the CH pump and TRVs are modulating.

In practice this won't happen because very low flow rates will result in very
little mixing of the water. The result would be that the top of the
radiator will be at full flow temperature and the bottom at return
temperature. It may be that the return is as low as 40 degrees but the top
will certainly be at 70 or whatever the flow rate is.

I tested this as an experiment some time ago by feeding a radiator normally
specified for 4kW output using a length of 8mm pipe. The effect was
exactly as described, so it is not what is wanted.



A condensing boiler mated to a heat bank/thermal store will be very
efficient. Using a store set to 70-75C and a blending valve on the boiler
flow/return to the store set to give a 22C to 25C drop of setpoint (say
50C), will be condensing the vast majority of the time. The valve also
maintains
stratification.

This is pointless. The boiler will not be operating at maximum efficiency
because efficiency does not suddenly improve at the temperature (52-54 degree
return). All that happens is that the *rate* of increase of efficiency with
reducing temperature will increase.

Therefore the notion of dinking around with blending valves to get the boiler
just into condensing mode and hence achieving some nirvana is false.

Added to this, if the store is maintained only at 70 degrees, it has little
advantage in terms of capacity compared with simple storage of the DHW.

In short, this idea will not work in terms of providing low radiator
temperatures, it won't maximise boiler efficiency and it won't do a good job
with the DHW either.




So, a simple, less complex, more reliable, condensing boiler can be used.


That's also bogus since the difference in cost of fully compensated quality
boilers is not because of the complexity (a temperature sensor is added and
the firmware in the controller does the work). The main reasons for higher
capital cost are in build quality, smaller production volume and the why does
a dog lick its balls syndrome.

In article ews.net,
Doctor Drivel wrote:
Richard Cranium, does the warden allow
you have a hot radiator on in this
weather?

Is doe the warden a relation of bob the builder?

I wonder if the warden lets them watch Bob on DVD?

Perhaps you'd lend him your set? After you've learnt everything you can
from them, obviously.

--
*When the going gets tough, use duct tape

Dave Plowman London SW
To e-mail, change noise into sound.

"Dave Plowman (News)" through a haze of senile
flatulence wrote in message ...
In article ews.net,
Doctor Drivel wrote:
Richard Cranium, does the warden allow
you have a hot radiator on in this
weather?

Is doe the warden a relation of bob the builder?

I wonder if the warden lets them watch Bob on DVD?

Perhaps

snip senile babble

He has Mat Monroe LPs you know.

"Andy Hall" aka Matt wrote in message
...
On Tue, 4 Jul 2006 14:03:55 +0100, Doctor Drivel wrote
(in article ews.net):


"Aidan" wrote in message
oups.com...

I was surprised by the amount of time
my modified modulating system
operates at less than 100%; probably
90% of the time and I didn't
change any radiators. You will achieve
worthwhile savings with a
condensing modulating boilers even
without changing radiators.

Only if it has the correct modulating control system. One that modulates
on
load compensation rather than maintaining a flow temperature set point.
These boilers are not cheap.

In terms of total cost of ownership and the required results over the
operating life of the system, this is not significant.

A heat bank/thermal store using TRVs
on all rads and an auto modulating pump
(Alpha) on the CH circuit , will slowly
inject high temp water into the rads
when the TRVs throttle back. This high
temp water then slowly mixes with the
cooler water in the rads. So you may
have 70C water in the rad flow pipe,
but the rads are very much cooler.
If the CH circuit demands 0.25kW of
heat, as a few TRV are just cracked
open, it just takes it from the store as
everything, the CH pump and TRVs
are modulating.

In practice this won't happen because
very low flow rates will result in very
little mixing of the water.

Matt, you just made that up.

The result would be that the top of the
radiator will be at full flow temperature
and the bottom at return
temperature.

It is clear you did make that up. "Most" flow through rad goes right across
the bottom. The hotter water makes the water rise to the top. This, when
there is little water injection to the rad will form mixing in the rad.

snip ill-informed Matt babbleness

Sad but true.