Has anyone got any thoughts on the correct setting for the temperature
dial on a condensing boiler please?

Its only marked MAX and MIN and has always been left on MAX since it
was installed a few years ago. Our HW stat is on 80C, because that is
what I want. Set the boiler output temperature too low and it will
constantly cycle on and off unable to achieve the demand.

Suggestions and your reasoning please?

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

Harry Bloomfield wrote:
Has anyone got any thoughts on the correct setting for the temperature
dial on a condensing boiler please?

Its only marked MAX and MIN and has always been left on MAX since it was
installed a few years ago. Our HW stat is on 80C, because that is what I
want. Set the boiler output temperature too low and it will constantly
cycle on and off unable to achieve the demand.

Suggestions and your reasoning please?

Setting it low should mean it runs continuously and if too low, will not
fulfil the demand.
If your HW system is designed to modify the boiler flow stat (some
more sophisticated boilers allow this) you might achieve your 80C DHW
(which IMHO is set too high but accept that you want what you want)

In my book the boiler needs to be set as low as possible whilst still
satisfying the demand. This should keep it in condensing mode as much as
possible.

On 14/01/2016 12:34, Harry Bloomfield wrote:
Has anyone got any thoughts on the correct setting for the temperature
dial on a condensing boiler please?

Its only marked MAX and MIN and has always been left on MAX since it was
installed a few years ago. Our HW stat is on 80C, because that is what I
want. Set the boiler output temperature too low and it will constantly
cycle on and off unable to achieve the demand.

Suggestions and your reasoning please?

Generally the lowest flow temperature that you can get away with, and
still achieve adequate heating and fast enough warm up, is the ideal. It
will result in the lowest return temperature and the greatest condensing
efficiency. As side benefits it also gives less creaks, clanks, and
groans from the metalwork of the radiators and pipes since there is less
temperature swing. Less "danger" from hot rads etc.

However the general problem with this approach is that on cold / high
heat loss days you may not be able to achieve the set temperature in the
house, and it poses a problem if you want to heat a cylinder to a high
temperature as in the case here.

The solution to this problem is via a system that supports split
temperature operation, (i.e. one that understands the difference between
running rads and heating a cylinder and uses a higher flow temp for the
the latter). The posh version being weather compensation, that also
understands when its cold outside and makes further adjustments to the
radiator flow temperature in response.

Not all boilers have the controls to do these things.


--
Cheers,

John.

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

On Thursday, 14 January 2016 12:34:06 UTC, Harry Bloomfield wrote:
Has anyone got any thoughts on the correct setting for the temperature
dial on a condensing boiler please?

Its only marked MAX and MIN and has always been left on MAX since it
was installed a few years ago. Our HW stat is on 80C, because that is
what I want. Set the boiler output temperature too low and it will
constantly cycle on and off unable to achieve the demand.

Suggestions and your reasoning please?

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

With most people, the lower temperature limitation is governed by the hot water needs.
Subject to the above, set it as low as you can get away with (ie keeping the house warm).

On 14/01/2016 13:42, John Rumm wrote:
On 14/01/2016 12:34, Harry Bloomfield wrote:
Has anyone got any thoughts on the correct setting for the temperature
dial on a condensing boiler please?

Its only marked MAX and MIN and has always been left on MAX since it was
installed a few years ago. Our HW stat is on 80C, because that is what I
want. Set the boiler output temperature too low and it will constantly
cycle on and off unable to achieve the demand.

Suggestions and your reasoning please?

snip
The solution to this problem is via a system that supports split
temperature operation, (i.e. one that understands the difference between
running rads and heating a cylinder and uses a higher flow temp for the
the latter). The posh version being weather compensation, that also
understands when its cold outside and makes further adjustments to the
radiator flow temperature in response.

Not all boilers have the controls to do these things.


Could you name some that do ?. I will be looking for a new boiler this
year, possibly, but not necessarily a combi

On 14/01/2016 19:02, Andrew wrote:
On 14/01/2016 13:42, John Rumm wrote:
On 14/01/2016 12:34, Harry Bloomfield wrote:
Has anyone got any thoughts on the correct setting for the temperature
dial on a condensing boiler please?

Its only marked MAX and MIN and has always been left on MAX since it was
installed a few years ago. Our HW stat is on 80C, because that is what I
want. Set the boiler output temperature too low and it will constantly
cycle on and off unable to achieve the demand.

Suggestions and your reasoning please?

snip
The solution to this problem is via a system that supports split
temperature operation, (i.e. one that understands the difference between
running rads and heating a cylinder and uses a higher flow temp for the
the latter). The posh version being weather compensation, that also
understands when its cold outside and makes further adjustments to the
radiator flow temperature in response.

Not all boilers have the controls to do these things.


Could you name some that do ?. I will be looking for a new boiler this
year, possibly, but not necessarily a combi

Pretty sure the Vaillant eco-tec supports split temperature. Might need
an extra box for weather compensation.

On 14/01/2016 12:34, Harry Bloomfield wrote:
Has anyone got any thoughts on the correct setting for the temperature
dial on a condensing boiler please?

Its only marked MAX and MIN and has always been left on MAX since it was
installed a few years ago. Our HW stat is on 80C, because that is what I
want. Set the boiler output temperature too low and it will constantly
cycle on and off unable to achieve the demand.

Suggestions and your reasoning please?

I run mine of max at all times .... control handed over to tank stat,
which cuts boiler off when it reached 65 degrees

"rick" wrote in message
...
On 14/01/2016 12:34, Harry Bloomfield wrote:
Has anyone got any thoughts on the correct setting for the temperature
dial on a condensing boiler please?

Its only marked MAX and MIN and has always been left on MAX since it was
installed a few years ago. Our HW stat is on 80C, because that is what I
want. Set the boiler output temperature too low and it will constantly
cycle on and off unable to achieve the demand.

Suggestions and your reasoning please?

I run mine of max at all times .... control handed over to tank stat,
which cuts boiler off when it reached 65 degrees


TBH I have never seen a tank stat that goes over 65 deg.

--
Adam

On 14/01/2016 19:02, Andrew wrote:
On 14/01/2016 13:42, John Rumm wrote:
On 14/01/2016 12:34, Harry Bloomfield wrote:
Has anyone got any thoughts on the correct setting for the temperature
dial on a condensing boiler please?

Its only marked MAX and MIN and has always been left on MAX since it was
installed a few years ago. Our HW stat is on 80C, because that is what I
want. Set the boiler output temperature too low and it will constantly
cycle on and off unable to achieve the demand.

Suggestions and your reasoning please?

snip
The solution to this problem is via a system that supports split
temperature operation, (i.e. one that understands the difference between
running rads and heating a cylinder and uses a higher flow temp for the
the latter). The posh version being weather compensation, that also
understands when its cold outside and makes further adjustments to the
radiator flow temperature in response.

Not all boilers have the controls to do these things.


Could you name some that do ?. I will be looking for a new boiler this
year, possibly, but not necessarily a combi

Most Vaillant, some WB, Some Viseman, and probably quite a number of
others. (I have not been looking at recent models for a few years).



--
Cheers,

John.

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

ARW used his keyboard to write :
"rick" wrote in message
...
On 14/01/2016 12:34, Harry Bloomfield wrote:
Has anyone got any thoughts on the correct setting for the temperature
dial on a condensing boiler please?

Its only marked MAX and MIN and has always been left on MAX since it was
installed a few years ago. Our HW stat is on 80C, because that is what I
want. Set the boiler output temperature too low and it will constantly
cycle on and off unable to achieve the demand.

Suggestions and your reasoning please?

I run mine of max at all times .... control handed over to tank stat, which
cuts boiler off when it reached 65 degrees


TBH I have never seen a tank stat that goes over 65 deg.

Drayton HTS-3 It has markings every 10C up to 80 then just a mark for
90C.

Thanks for the replies. It is just a simple basic condensing boiler, no
separate sensing for HW and heating, so I am stuck with the MAX boiler
setting.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

Harry Bloomfield wrote:
ARW used his keyboard to write :
"rick" wrote in message
...
On 14/01/2016 12:34, Harry Bloomfield wrote:
Has anyone got any thoughts on the correct setting for the temperature
dial on a condensing boiler please?

Its only marked MAX and MIN and has always been left on MAX since it
was
installed a few years ago. Our HW stat is on 80C, because that is
what I
want. Set the boiler output temperature too low and it will constantly
cycle on and off unable to achieve the demand.

Suggestions and your reasoning please?

I run mine of max at all times .... control handed over to tank stat,
which cuts boiler off when it reached 65 degrees


TBH I have never seen a tank stat that goes over 65 deg.

Drayton HTS-3 It has markings every 10C up to 80 then just a mark for 90C.

Thanks for the replies. It is just a simple basic condensing boiler, no
separate sensing for HW and heating, so I am stuck with the MAX boiler
setting.

With your electronic skills, you should be able to modify the boiler for
dual temp setting.

The sensor is usually a thermistor. I bought one as a spare part on ebay
for a few quid and measured it at various temperatures and found that it
closely complied with one of the standard curves for thermistor sensors.

With a relay you can switch in an extra resistor (or variable resistor)
in series or parallel the flow temp sensor and drive the relay coil from
the DHW demand signal to give one setting for CH and a boost for DHW.

On 14/01/2016 21:45, ARW wrote:
"rick" wrote in message
...
On 14/01/2016 12:34, Harry Bloomfield wrote:
Has anyone got any thoughts on the correct setting for the temperature
dial on a condensing boiler please?

Its only marked MAX and MIN and has always been left on MAX since it was
installed a few years ago. Our HW stat is on 80C, because that is what I
want. Set the boiler output temperature too low and it will constantly
cycle on and off unable to achieve the demand.

Suggestions and your reasoning please?

I run mine of max at all times .... control handed over to tank stat,
which cuts boiler off when it reached 65 degrees


TBH I have never seen a tank stat that goes over 65 deg.



Eh ? ..... my tank stat goes up to 90

On 15/01/2016 14:16, Bob Minchin wrote:
Harry Bloomfield wrote:


With your electronic skills, you should be able to modify the boiler
for dual temp setting.

The sensor is usually a thermistor. I bought one as a spare part on
ebay for a few quid and measured it at various temperatures and found
that it closely complied with one of the standard curves for
thermistor sensors.

With a relay you can switch in an extra resistor (or variable
resistor) in series or parallel the flow temp sensor and drive the
relay coil from the DHW demand signal to give one setting for CH and
a boost for DHW.


or use an IN4148 diode :-)

On 15/01/2016 02:43, John Rumm wrote:
On 14/01/2016 19:02, Andrew wrote:
On 14/01/2016 13:42, John Rumm wrote:
On 14/01/2016 12:34, Harry Bloomfield wrote:
Has anyone got any thoughts on the correct setting for the temperature
dial on a condensing boiler please?

Its only marked MAX and MIN and has always been left on MAX since it
was
installed a few years ago. Our HW stat is on 80C, because that is
what I
want. Set the boiler output temperature too low and it will constantly
cycle on and off unable to achieve the demand.

Suggestions and your reasoning please?

snip
The solution to this problem is via a system that supports split
temperature operation, (i.e. one that understands the difference between
running rads and heating a cylinder and uses a higher flow temp for the
the latter). The posh version being weather compensation, that also
understands when its cold outside and makes further adjustments to the
radiator flow temperature in response.

Not all boilers have the controls to do these things.


Could you name some that do ?. I will be looking for a new boiler this
year, possibly, but not necessarily a combi

Most Vaillant, some WB, Some Viseman, and probably quite a number of
others. (I have not been looking at recent models for a few years).



I run my Valliant ecotec Vaillant with HW at ~50C and CH around 60C.
Have the CH low in Autumn/Spring and wind it up if necessary when it get
really cold and windy. ( House is 1800 with stone rubble walls etc and
thus poorly insulated)

In article ,
Bob Minchin writes:
With your electronic skills, you should be able to modify the boiler for
dual temp setting.

The sensor is usually a thermistor. I bought one as a spare part on ebay
for a few quid and measured it at various temperatures and found that it
closely complied with one of the standard curves for thermistor sensors.

With a relay you can switch in an extra resistor (or variable resistor)
in series or parallel the flow temp sensor and drive the relay coil from
the DHW demand signal to give one setting for CH and a boost for DHW.

I would say you should be switching to a second thermostat setting,
and not changing the temperature sensing, which may well do other
things too such as lock-out if the boiler overheats, which you might
end up defeating.

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

On 15/01/2016 19:31, Robert wrote:
On 15/01/2016 02:43, John Rumm wrote:
On 14/01/2016 19:02, Andrew wrote:
On 14/01/2016 13:42, John Rumm wrote:
On 14/01/2016 12:34, Harry Bloomfield wrote:
Has anyone got any thoughts on the correct setting for the temperature
dial on a condensing boiler please?

Its only marked MAX and MIN and has always been left on MAX since it
was
installed a few years ago. Our HW stat is on 80C, because that is
what I
want. Set the boiler output temperature too low and it will constantly
cycle on and off unable to achieve the demand.

Suggestions and your reasoning please?

snip
The solution to this problem is via a system that supports split
temperature operation, (i.e. one that understands the difference
between
running rads and heating a cylinder and uses a higher flow temp for the
the latter). The posh version being weather compensation, that also
understands when its cold outside and makes further adjustments to the
radiator flow temperature in response.

Not all boilers have the controls to do these things.


Could you name some that do ?. I will be looking for a new boiler this
year, possibly, but not necessarily a combi

Most Vaillant, some WB, Some Viseman, and probably quite a number of
others. (I have not been looking at recent models for a few years).



I run my Valliant ecotec Vaillant with HW at ~50C and CH around 60C.
Have the CH low in Autumn/Spring and wind it up if necessary when it get
really cold and windy. ( House is 1800 with stone rubble walls etc and
thus poorly insulated)

I use fitted the weather compensator when I did mine. That means the
heating temperature is driven by a combination of the exterior
temperature and the selected "curve" in the controller. You select a
curve that matches the heat loss of the house.

That means in the less cold periods it will often run flow temperatures
in the 40s and 50s, and only ramp up to over 60 when it starts getting
close to zero. The water however is always heated to 60, and then it
does an anti salmonella cycle on Wednesdays to heat it to 70.

--
Cheers,

John.

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

On 14/01/2016 19:02, Andrew wrote:
possibly, but not necessarily a combi

Don't do that.

With a tank at least when the boiler goes wrong you can turn the
immersion on and have a hot bath. And fill the bath in less than 20
minutes. And have the tank, not the boiler scale up...

Andy