I have decided my Ideal Icos HE18 is beyond sensible repair cost, I
have chucked enough at it, so I am looking now for a replacement...

It needs to be a regular, vented system type boiler, but if possible
with separate boiler output temperature controls when heating the hot
water tank, to that when heating the radiators. Yes I presently have a
room stat and a water tank stat. I just like the hot water to be able
to be very hot 80C, I appreciate that is above the efficient condensing
range, but to heat the radiators the boiler output temperature need not
be quite so hot. 18+ Kw needed as present boiler is adequate. The
predecessor to that was around 32Kw, but some good insulation has made
that high an output unnecessary.

I had no input into the boiler make last time around, this time I am
looking to Vailant or Worcester/Bosch for a more reliable boiler.

On 24/03/2018 19:25, Harry Bloomfield wrote:
I have decided my Ideal Icos HE18 is beyond sensible repair cost, I have
chucked enough at it, so I am looking now for a replacement...

It needs to be a regular, vented system type boiler, but if possible
with separate boiler output temperature controls when heating the hot
water tank, to that when heating the radiators. Yes I presently have a
room stat and a water tank stat. I just like the hot water to be able to
be very hot 80C, I appreciate that is above the efficient condensing
range, but to heat the radiators the boiler output temperature need not
be quite so hot. 18+ Kw needed as present boiler is adequate. The
predecessor to that was around 32Kw, but some good insulation has made
that high an output unnecessary.

I had no input into the boiler make last time around, this time I am
looking to Vailant or Worcester/Bosch for a more reliable boiler.

I've a Vaillant Greenstar of some sort, it has separate controls for hot
water and radiators but TBH I'm not sure how it works. All the manuals
are easy to download.

I have a simple W plan and IIRC the diverter is switched by the cylinder
stat. Don't know if the boiler temperature is controlled at the same
time with the default "simple" control system.

Boiler has been very reliable.

newshound wrote:
On 24/03/2018 19:25, Harry Bloomfield wrote:
I have decided my Ideal Icos HE18 is beyond sensible repair cost, I
have chucked enough at it, so I am looking now for a replacement...

It needs to be a regular, vented system type boiler, but if possible
with separate boiler output temperature controls when heating the hot
water tank, to that when heating the radiators. Yes I presently have a
room stat and a water tank stat. I just like the hot water to be able
to be very hot 80C, I appreciate that is above the efficient
condensing range, but to heat the radiators the boiler output
temperature need not be quite so hot. 18+ Kw needed as present boiler
is adequate. The predecessor to that was around 32Kw, but some good
insulation has made that high an output unnecessary.

I had no input into the boiler make last time around, this time I am
looking to Vailant or Worcester/Bosch for a more reliable boiler.

I've a Vaillant Greenstar of some sort, it has separate controls for hot
water and radiators but TBH I'm not sure how it works. All the manuals
are easy to download.

I have a simple W plan and IIRC the diverter is switched by the cylinder
stat. Don't know if the boiler temperature is controlled at the same
time with the default "simple" control system.

Boiler has been very reliable.
Isn't Greenstar a WB model name?

On 24/03/18 19:25, Harry Bloomfield wrote:
I have decided my Ideal Icos HE18 is beyond sensible repair cost, I have
chucked enough at it, so I am looking now for a replacement...

It needs to be a regular, vented system type boiler, but if possible
with separate boiler output temperature controls when heating the hot
water tank, to that when heating the radiators. Yes I presently have a
room stat and a water tank stat. I just like the hot water to be able to
be very hot 80C, I appreciate that is above the efficient condensing
range, but to heat the radiators the boiler output temperature need not
be quite so hot. 18+ Kw needed as present boiler is adequate. The
predecessor to that was around 32Kw, but some good insulation has made
that high an output unnecessary.

I had no input into the boiler make last time around, this time I am
looking to Vailant or Worcester/Bosch for a more reliable boiler.

I heavily researched Viessman and Worcester Bosch:

I went with WB, but I would not be that unhappy with Viessmann either.

Pros and cons (WB substantiated, Viessmann is based off anecdotal
evidence and on paper specs - at least one person here has a Viessmann
and will probably comment)


WB:

1) Highest DHW output for a wall mounted unit;
2) Reasonable price;
3) Easy to wire and operated (either dumb knobs or LCD depending on model)
4) Quiet and well behaved;
5) According to my Gas Fitter, WB parts are quicker to get hold off than
Viessmann, maybe because it's more common???? *Anecdotal*


Viessmann:
1) Weather compensation that WB don't have (unless you buy their fancy
controller that precludes using your own controls) - you only need add
the sensor to a north wall (or shaded area I assume);

2) Slightly more "Waitrose" than WB's "Sainsbury" - stainless heat
exchanger supposed to be a selling point.


I went WB mostly because it had enough DHW power in theory to run a
shower and a bath (latter is throttled to 20l/min by flow restrictors).


I do miss not having weather comp, but I have measured the flow and
return temps for each number on the knob - and have a rough manual scale
of "this time of year, turn knob to 4" kinda thing.

On 24/03/18 20:32, Bob Minchin wrote:

Boiler has been very reliable.
Isn't Greenstar a WB model name?

Yes.

On 24/03/2018 20:32, Bob Minchin wrote:
newshound wrote:
On 24/03/2018 19:25, Harry Bloomfield wrote:
I have decided my Ideal Icos HE18 is beyond sensible repair cost, I
have chucked enough at it, so I am looking now for a replacement...

It needs to be a regular, vented system type boiler, but if possible
with separate boiler output temperature controls when heating the hot
water tank, to that when heating the radiators. Yes I presently have a
room stat and a water tank stat. I just like the hot water to be able
to be very hot 80C, I appreciate that is above the efficient
condensing range, but to heat the radiators the boiler output
temperature need not be quite so hot. 18+ Kw needed as present boiler
is adequate. The predecessor to that was around 32Kw, but some good
insulation has made that high an output unnecessary.

I had no input into the boiler make last time around, this time I am
looking to Vailant or Worcester/Bosch for a more reliable boiler.

I've a Vaillant Greenstar of some sort, it has separate controls for hot
water and radiators but TBH I'm not sure how it works. All the manuals
are easy to download.

I have a simple W plan and IIRC the diverter is switched by the cylinder
stat. Don't know if the boiler temperature is controlled at the same
time with the default "simple" control system.

Boiler has been very reliable.
Isn't Greenstar a WB model name?


Oops yes I mean ecoTEC! But WB and Vaillant seem to rate equally highly
both here and in Which?

It happens that Tim Watts formulated :
I went WB mostly because it had enough DHW power in theory to run a shower
and a bath (latter is throttled to 20l/min by flow restrictors).

I don't want/need DHW, I like stored HW.

On 24/03/18 20:48, Harry Bloomfield wrote:
It happens that Tim Watts formulated :
I went WB mostly because it had enough DHW power in theory to run a
shower and* a bath (latter is throttled to 20l/min by flow restrictors).

I don't want/need DHW, I like stored HW.

Well then - look at there non combi range - most of the Pros and cons
are likely to be much the same. But you could easily look at the
Viessmann with weather comp.

In message , Tim Watts
writes
On 24/03/18 20:48, Harry Bloomfield wrote:
It happens that Tim Watts formulated :
I went WB mostly because it had enough DHW power in theory to run a
shower and* a bath (latter is throttled to 20l/min by flow restrictors).
I don't want/need DHW, I like stored HW.

Well then - look at there non combi range - most of the Pros and cons
are likely to be much the same. But you could easily look at the
Viessmann with weather comp.

:-) I have just fired up a 30kW Viessmann in the cottage. I'm not yet
familiar with the controls. Weather comp yes. Different temps. for hot
water and heating, yes I think. You can certainly switch off the heating
for summer. Clear display.

I have a 30kW condensing boiler and new flue for anyone offering an
appreciative home. 5 years old (2 years work and 3 resting). Potterton
precision.

--
Tim Lamb

Tim Lamb wrote on 24/03/2018 :
:-) I have just fired up a 30kW Viessmann in the cottage. I'm not yet
familiar with the controls. Weather comp yes. Different temps. for hot water
and heating, yes I think. You can certainly switch off the heating for
summer. Clear display.

I cannot seem to see a name for the independent boiler output
temperature limiting - anyone, what is it called?

Is it available on a regular, open vented boiler?

On 24/03/2018 19:25, Harry Bloomfield wrote:
I have decided my Ideal Icos HE18 is beyond sensible repair cost, I have
chucked enough at it, so I am looking now for a replacement...

It needs to be a regular, vented system type boiler, but if possible
with separate boiler output temperature controls when heating the hot
water tank, to that when heating the radiators. Yes I presently have a
room stat and a water tank stat. I just like the hot water to be able to
be very hot 80C, I appreciate that is above the efficient condensing
range, but to heat the radiators the boiler output temperature need not
be quite so hot. 18+ Kw needed as present boiler is adequate. The
predecessor to that was around 32Kw, but some good insulation has made
that high an output unnecessary.

I had no input into the boiler make last time around, this time I am
looking to Vailant or Worcester/Bosch for a more reliable boiler.


Vaillant 400 series do vented and split temperature operation. They can
also do weather compensation if you want. Been very pleased with my 600
series system boiler so far...

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On 24/03/2018 21:25, Harry Bloomfield wrote:
Tim Lamb wrote on 24/03/2018 :
:-) I have just fired up a 30kW Viessmann in the cottage. I'm not yet
familiar with the controls. Weather comp yes. Different temps. for hot
water and heating, yes I think. You can certainly switch off the
heating for summer. Clear display.

I cannot seem to see a name for the independent boiler output
temperature limiting - anyone, what is it called?

Not quite sure what you mean? Or are you referring to "split temperature
operation" - the ability to run the heating and hot water at different
flow temperatures (or the heating under the control of a weather
compensator, and the HW on fixed temp)

Is it available on a regular, open vented boiler?

Split temp, yup see my other post. If Gremlin95 is about, he knows more
about the new range than I do.

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

John Rumm explained :
Split temp, yup see my other post. If Gremlin95 is about, he knows more about
the new range than I do.

Yes, that's it, 'split temperature' was the expression I was seeking.
Thanks !

John Rumm laid this down on his screen :
Vaillant 400 series do vented and split temperature operation. They can also
do weather compensation if you want. Been very pleased with my 600 series
system boiler so far...

Thanks, I will take a look at those. I just to be armed for when a guy
comes around to give a quote..

In article ,
Harry Bloomfield wrote:
It needs to be a regular, vented system type boiler,

You might find a maker won't warrant an open vent type these days. And
many system boilers come with a pressure vessel installed.

--
*And the cardiologist' s diet: - If it tastes good spit it out.

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

On 24/03/2018 21:25, Harry Bloomfield wrote:
Tim Lamb wrote on 24/03/2018 :
:-) I have just fired up a 30kW Viessmann in the cottage. I'm not yet
familiar with the controls. Weather comp yes. Different temps. for hot
water and heating, yes I think. You can certainly switch off the
heating for summer. Clear display.

I cannot seem to see a name for the independent boiler output
temperature limiting - anyone, what is it called?

Is it available on a regular, open vented boiler?

Get BG in for a quote. Obviously do not uses them but have a holiday
with the money saved!

--
Adam

Harry Bloomfield was thinking very hard :
Split temp, yup see my other post. If Gremlin95 is about, he knows more
about the new range than I do.

Yes, that's it, 'split temperature' was the expression I was seeking. Thanks
!

Having enquired with both Worcester and Vaillant, neither offers a
regular / conventional boiler which includes an ability to set two
separate output temperatures for heating and hot water. A gap in the
market me thinks, for an enterprising boiler manufacturer.

A single boiler setting stat is fine, where a consumer is happy with a
lower temperature of boiler output for both heating and HW, but less
useful for someone like me who likes their HW hot - where there is a
possibility for some saving on keeping radiator temperatures lower, so
the boiler remains in the more efficient condensing temperature range.

I suppose I could do an add-on stat, mounted on the flow pipe to the
radiators, to shut the boiler down at say 60C leaving the boilers own
stat set to maximum ? Would that not wreck the boiler's efficiency?

My current scheme is to manually tweak the room stat, gradually raising
the room temperature to the desired temperature, over a couple of
hours. Otherwise the heating system over reacts if the stat is set to
desired in one single movement of the dial.

On Monday, 26 March 2018 14:55:58 UTC+1, Harry Bloomfield wrote:
Harry Bloomfield was thinking very hard :
Split temp, yup see my other post. If Gremlin95 is about, he knows more
about the new range than I do.

Yes, that's it, 'split temperature' was the expression I was seeking. Thanks
!

Having enquired with both Worcester and Vaillant, neither offers a
regular / conventional boiler which includes an ability to set two
separate output temperatures for heating and hot water.

My Vaillant does that.

A gap in the
market me thinks, for an enterprising boiler manufacturer.

A single boiler setting stat is fine, where a consumer is happy with a
lower temperature of boiler output for both heating and HW, but less
useful for someone like me who likes their HW hot - where there is a
possibility for some saving on keeping radiator temperatures lower, so
the boiler remains in the more efficient condensing temperature range.

I suppose I could do an add-on stat, mounted on the flow pipe to the
radiators, to shut the boiler down at say 60C leaving the boilers own
stat set to maximum ? Would that not wreck the boiler's efficiency?

quite the opposite, it forces it to condense more of the time.

My current scheme is to manually tweak the room stat, gradually raising
the room temperature to the desired temperature, over a couple of
hours. Otherwise the heating system over reacts if the stat is set to
desired in one single movement of the dial.


NT

brought next idea :
My Vaillant does that.

Is that a conventional / open vented boiler, if so you need to let
Vaillant know that they do actually produce one.

I am aware that it is often fitted to sytem and combi boilers.

On 26/03/2018 14:55, Harry Bloomfield wrote:
Harry Bloomfield was thinking very hard :
Split temp, yup see my other post. If Gremlin95 is about, he knows
more about the new range than I do.

Yes, that's it, 'split temperature' was the expression I was seeking.
Thanks !

Having enquired with both Worcester and Vaillant, neither offers a
regular / conventional boiler which includes an ability to set two
separate output temperatures for heating and hot water. A gap in the
market me thinks, for an enterprising boiler manufacturer.



The 400 used to... Looking at:

https://vaillantgroup.intellirespons...5%2 0-%202015)

You can see that one has the two temperature controls on the front.

However the current model has a radically different internal layout:

https://vaillantgroup.intellirespons... 0-%20Present)

But, a quick read of the manual still suggests that it supports separate
CH and DHW temperature controls:

https://www.vaillant.co.uk/downloads...1-1-931512.pdf

It also still has a connection for an external temperature sensor -
suggesting it ought to work with the weather compensating controls. If
that is true, then it must support split temp operation...

Yup:

https://www.vaillant.co.uk/for-insta...ats-22272.html

Says that it works on all current models.

A single boiler setting stat is fine, where a consumer is happy with a
lower temperature of boiler output for both heating and HW, but less
useful for someone like me who likes their HW hot - where there is a
possibility for some saving on keeping radiator temperatures lower, so
the boiler remains in the more efficient condensing temperature range.

I suppose I could do an add-on stat, mounted on the flow pipe to the
radiators, to shut the boiler down at say 60C leaving the boilers own
stat set to maximum ? Would that not wreck the boiler's efficiency?

My current scheme is to manually tweak the room stat, gradually raising
the room temperature to the desired temperature, over a couple of hours.
Otherwise the heating system over reacts if the stat is set to desired
in one single movement of the dial.

On mine (600 series system boiler) I let the weather compensator chose
the CH flow temp (at installation you can select a variety of response
curves that dictate how aggressively it ramps up the flow temperature in
response to the external temperature falling). That tends to mean for
the parts of the year where it not that cold out, it often runs flow
temperatures in the 40 to 50 degree range.

The DHW I have set to 60 (its set at the boiler - there is no
conventional cylinder stat - just a NTC thermister in a pocket that
connects to the wiring centre). The boiler tends to run flow
temperatures appropriate for that, usually doing the first bit of the
recharge at around 60 to eek out more efficency, then ramping up to 75
ish for the last bit. I also have it set to do an anti-legionella cycle
once per week - where it will heat the cylinder to 75 once. (its a hard
water area, so lower cylinder temps result is less scale deposition).


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On Monday, 26 March 2018 21:39:44 UTC+1, Harry Bloomfield wrote:
tabbypurr brought next idea :

My Vaillant does that.

Is that a conventional / open vented boiler, if so you need to let
Vaillant know that they do actually produce one.

I am aware that it is often fitted to sytem and combi boilers.

condensing non-combi, 400 series IIRC. IIRC it's an installed option not always present.


NT

John Rumm was thinking very hard :
https://www.vaillant.co.uk/downloads...1-1-931512.pdf

It also still has a connection for an external temperature sensor -
suggesting it ought to work with the weather compensating controls. If that
is true, then it must support split temp operation...

Yup:

https://www.vaillant.co.uk/for-insta...ats-22272.html

Says that it works on all current models.

Thanks, you are correct - but I wonder why their help desk didn't point
me in that direction?

On 27/03/2018 03:39, wrote:
On Monday, 26 March 2018 21:39:44 UTC+1, Harry Bloomfield wrote:
tabbypurr brought next idea :

My Vaillant does that.

Is that a conventional / open vented boiler, if so you need to let
Vaillant know that they do actually produce one.

I am aware that it is often fitted to sytem and combi boilers.

condensing non-combi, 400 series IIRC. IIRC it's an installed option not always present.

If you pair it with conventional controls, then it won't be able to work
out what function its supposed to be doing - so then it will use the CH
flow set point temp all the time.


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

On Tuesday, 27 March 2018 11:45:14 UTC+1, John Rumm wrote:
On 27/03/2018 03:39, tabbypurr wrote:
On Monday, 26 March 2018 21:39:44 UTC+1, Harry Bloomfield wrote:
tabbypurr brought next idea :

My Vaillant does that.

Is that a conventional / open vented boiler, if so you need to let
Vaillant know that they do actually produce one.

I am aware that it is often fitted to sytem and combi boilers.

condensing non-combi, 400 series IIRC. IIRC it's an installed option not always present.

If you pair it with conventional controls, then it won't be able to work
out what function its supposed to be doing - so then it will use the CH
flow set point temp all the time.

I presume the boiler gets 2 separate call for heat signals, I don't remember.


NT

On 27/03/2018 14:03, wrote:
On Tuesday, 27 March 2018 11:45:14 UTC+1, John Rumm wrote:
On 27/03/2018 03:39, tabbypurr wrote:
On Monday, 26 March 2018 21:39:44 UTC+1, Harry Bloomfield wrote:
tabbypurr brought next idea :

My Vaillant does that.

Is that a conventional / open vented boiler, if so you need to let
Vaillant know that they do actually produce one.

I am aware that it is often fitted to sytem and combi boilers.

condensing non-combi, 400 series IIRC. IIRC it's an installed option not always present.

If you pair it with conventional controls, then it won't be able to work
out what function its supposed to be doing - so then it will use the CH
flow set point temp all the time.

I presume the boiler gets 2 separate call for heat signals, I don't remember.

Ideally it has a NTC probe connected to the cylinder, and a "smart"
wiring centre that is connected to the boiler via eBus to allow it to
control the zone valves (Y or S/S+ only I would guess).

Then it can work out what to do based on the program set on its
programmer (i.e. what times of day the DHW can be recharged), and the
input from the sensor giving the current cylinder temp. Then it will set
the valves for DHW only heating, and run appropriate flow temperatures
for the DHW reheat.

(the boiler can also control a secondary circulation pump and a recharge
pump as well if required)

It seems smart enough to not try and run both CH and DHW at the same
time (therefore avoiding running the rads at DHW temperatures), even if
the programs are overlapped. I did not realise it would do that at
first and programmed them to run at different times. These days I tend
to have DHW "on" for quite long periods shared with the heating, and
that allows it to work out when there is a big demand for hot water and
switch to reheating faster so you get more apparent hot water capacity
from the cylinder.


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/