Hi.


i have a vaillant ecomax 613 condensing boiler with indirect cylinder.

at the moment the boiler thermostat is set to 65 deg and the cylinder
to 58 deg.

my question is it better to set up to boiler thermostat to max ? will
the boiler still work in condensing mode ?

my gas engineer told my that the boiler is very efficient so it is OK
to run the hot water 24HR a day. we take 3 baths a day 2 in the
morning and one in the evening. should i set the programmer to run the
hot water for those times or let it run all the time ? what it cheaper.

"Golan" wrote in message
...
Hi.


i have a vaillant ecomax 613 condensing boiler with indirect cylinder.

at the moment the boiler thermostat is set to 65 deg and the cylinder
to 58 deg.

my question is it better to set up to boiler thermostat to max ? will
the boiler still work in condensing mode ?

my gas engineer told my that the boiler is very efficient so it is OK
to run the hot water 24HR a day. we take 3 baths a day 2 in the
morning and one in the evening. should i set the programmer to run the
hot water for those times or let it run all the time ? what it cheaper.

Run at the lowest temperature you can get away with. If 65 is OK for DHW and
heating then leave it. Time the DHW. The cylinder may lose heat during the
night and it is reheated unnecessarily during the night.

On Tue, 27 Nov 2007 16:51:17 UTC, Golan wrote:

Hi.


i have a vaillant ecomax 613 condensing boiler with indirect cylinder.

at the moment the boiler thermostat is set to 65 deg and the cylinder
to 58 deg.

my question is it better to set up to boiler thermostat to max ? will
the boiler still work in condensing mode ?

It will condense better if you keep it at the lowest setting consistent
with getting the heat you require.

my gas engineer told my that the boiler is very efficient so it is OK
to run the hot water 24HR a day.

Well, no matter how efficient ist is, it's always going to be cheaper
NOT to run it 24 hours a day.

Think about it. Rate of heat loss from the cylinder is proportional to
the temperature difference between it and its surroundings. As the
cylinder cools, its heat loss slows. If you keep it hot all the time,
its heat loss will be greater. Keeping it hot thus costs more than
letting it cool, and just putting the lost heat back.

So, run the boiler only when you need to heat the cylinder. Don't heat
it at night, or during the working day when you're not there.

--
The information contained in this post is copyright the
poster, and specifically may not be published in, or used by
http://www.diybanter.com

Golan wrote in
news:ec4690a8-b340-4d8e-987c-732b73ac3732
@y5g2000hsf.googlegroups.com:

Hi.


i have a vaillant ecomax 613 condensing boiler with indirect
cylinder.

at the moment the boiler thermostat is set to 65 deg and the
cylinder
to 58 deg.

my question is it better to set up to boiler thermostat to
max ? will
the boiler still work in condensing mode ?

The boiler would be running at its most efficient when the
return water
temp to the boiler is 54c Whether that will be sufficient in
cold
weather depends on your rad sizes and how much water you like
in your
bath.



my gas engineer told my that the boiler is very efficient so
it is OK
to run the hot water 24HR a day. we take 3 baths a day 2 in
the
morning and one in the evening. should i set the programmer
to run the
hot water for those times or let it run all the time ? what
it
cheaper.


No timed twice daily would be better.

In article ,
John writes:
Golan wrote in
news:ec4690a8-b340-4d8e-987c-732b73ac3732
@y5g2000hsf.googlegroups.com:

Hi.


i have a vaillant ecomax 613 condensing boiler with indirect cylinder.

at the moment the boiler thermostat is set to 65 deg and the cylinder
to 58 deg.

my question is it better to set up to boiler thermostat to max ? will
the boiler still work in condensing mode ?

The boiler would be running at its most efficient when the
return water
temp to the boiler is 54c

It still gets even more efficient at lower temperatures than that.
My condensing boiler runs at 40C return temperature for heating,
but the radiators were sized for low temperature operation.

A fast recovery cylinder will return the water to the boiler at
not much above the water temperature of the cylinder at the base
of the coil, so even if heating to 65C, much of the reheat time
will operate in condensing mode, until the return temperature
gets above 55C. With a standard (non-fast recovery) cylinder,
the return water is usually much hotter than the cylinder water
as the heat transfer to the cylinder water is not as effective.

Whether that will be sufficient in
cold
weather depends on your rad sizes and how much water you like
in your
bath.

If the same boiler does heating and hot water and doesn't have
independant temperature controls for each, then it's not possible
to reap the most efficient operation of the heating, as that will
be too cold for the hot water.

my gas engineer told my that the boiler is very efficient so it is OK
to run the hot water 24HR a day. we take 3 baths a day 2 in the
morning and one in the evening. should i set the programmer to run the
hot water for those times or let it run all the time ? what it
cheaper.

No timed twice daily would be better.

It's a shame how few heating installers actually understand the
physics behind their trade.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

(Andrew Gabriel) wrote in
:

In article ,


at the moment the boiler thermostat is set to 65 deg and
the cylinder
to 58 deg.

my question is it better to set up to boiler thermostat to
max ? will
the boiler still work in condensing mode ?

The boiler would be running at its most efficient when the
return water
temp to the boiler is 54c

It still gets even more efficient at lower temperatures than
that.
My condensing boiler runs at 40C return temperature for
heating,

True but I was replying to OP and making some assumptions
based on his plumbers comments
I.e. I would be surprised if radiators have been replaced and
resized to allow such a low return temp.
And I think it's only the ecomax combi that has a separate HW
temp setting.

On Thu, 29 Nov 2007 16:06:41 +0100, John wrote:

(Andrew Gabriel) wrote in
:

In article ,


at the moment the boiler thermostat is set to 65 deg and
the cylinder
to 58 deg.

my question is it better to set up to boiler thermostat to
max ? will
the boiler still work in condensing mode ?

The boiler would be running at its most efficient when the return
water
temp to the boiler is 54c

It still gets even more efficient at lower temperatures than
that.
My condensing boiler runs at 40C return temperature for
heating,

True but I was replying to OP and making some assumptions based on his
plumbers comments
I.e. I would be surprised if radiators have been replaced and resized to
allow such a low return temp. And I think it's only the ecomax combi
that has a separate HW temp setting.


I believe AG may have done that for himself. I doubt that serviceable
radiators are worth replacing with oversized units on fuel efficiency
grounds. But with a new system you would try to design/guesstimate for
cooler return temps.

Many many combis have seperate controls for heating and the MAXIMUM HW
temp, even really low end units.

There are only a few quite high end models for non combis which have
different setting for HW mode and heating mode, and then only in the
larger units.



--
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
Choosing a Boiler FAQ http://www.makewrite.demon.co.uk/BoilerChoice.html

Ed Sirett wrote in news:finevc$1ej
:

On Thu, 29 Nov 2007 16:06:41 +0100, John wrote:

(Andrew Gabriel) wrote in
:

In article ,


at the moment the boiler thermostat is set to 65 deg and
the cylinder
to 58 deg.

my question is it better to set up to boiler thermostat
to
max ? will
the boiler still work in condensing mode ?

The boiler would be running at its most efficient when
the return
water
temp to the boiler is 54c

It still gets even more efficient at lower temperatures
than
that.
My condensing boiler runs at 40C return temperature for
heating,

True but I was replying to OP and making some assumptions
based on his
plumbers comments
I.e. I would be surprised if radiators have been replaced
and resized to
allow such a low return temp. And I think it's only the
ecomax combi
that has a separate HW temp setting.


I believe AG may have done that for himself. I doubt that
serviceable
radiators are worth replacing with oversized units on fuel
efficiency
grounds. But with a new system you would try to
design/guesstimate for
cooler return temps.


Yes that was the assumption I was making in my reply to the OP


Many many combis have seperate controls for heating and the
MAXIMUM HW
temp, even really low end units.


I wasn't suggesting that the ecomax combi was the only one
with a separate HW control, more that the OPs ecomax system or
heatonly boiler did not have this facility whereas the combi
variant does.



There are only a few quite high end models for non combis
which have
different setting for HW mode and heating mode, and then
only in the
larger units.

Yes like Vaillants own EcoTec plus 415, although hardly
classified as large at 15Kw.
Unless you were referring to case dimensions :P


John.