Hi All,

I am going to fitting a vacuum tube solar panel for water heating, and combine this with a solar store (using a plate heat exchanger to supply mains hot water). i am also in the process of fitting a wood burning stove with a back boiler, that i plan to link to the thermal store. With these two systems i should have hot water for a fair amount of the time, however, there are times when the solar panels are not working and the wood burning stove is not convient, and the hot water is going to need a top up. So i plan to run the 'hot' water through a Combi boiler to 'assist' the hot water. The combi will also run the central heating system.

My problem is that all of the major boiler manufacturers i have spoken to say that their systems will not work with a warm/hot input. Does anyone know who does? I know that it is offered by one company (Eco-Home?) but i have never heard of them.

Many thanks in advance for any help that you can give...

Regards,

AbingdonBoy.

My problem is that all of the major boiler manufacturers i have spoken
to say that their systems will not work with a warm/hot input. Does
anyone know who does? I know that it is offered by one company
(Eco-Home?) but i have never heard of them.

I'd run the DHW straight off the heat bank. Use the gas boiler to heat that,
rather than attempting to boost the tank output. Consider running the rads
off the heatbank if the solar is going to provide significant heat. In
spring/autumn, solar heating isn't such a bad idea. Obviously, in the depths
of winter, the load will be too high and the solar energy too low to be
practical.

Christian.

"AbingdonBoy" wrote in message
...

Hi All,

I am going to fitting a vacuum tube solar panel for water heating, and
combine this with a solar store (using a plate heat exchanger to supply
mains hot water). i am also in the process of fitting a wood burning
stove with a back boiler, that i plan to link to the thermal store.
With these two systems i should have hot water for a fair amount of the
time, however, there are times when the solar panels are not working and
the wood burning stove is not convient, and the hot water is going to
need a top up. So i plan to run the 'hot' water through a Combi boiler
to 'assist' the hot water. The combi will also run the central heating
system.


My neighbour has recently had a solar system installed which runs its
heated mains pressure output through his Worcester Bosch CDi
I have an invite to go round to see it but as yet have not done so. From
what I hear so far it works just fine. The combi does not fire when the
input is hot but cuts in if it is not. It then modulates to match the
temperature-raising heat need.
I can forsee a problem with a wood burner raising the input temperature "too
high" which may need a thermostatic blending valve to keep the boiler mains
input within acceptable levels

On Thu, 20 Oct 2005 14:42:25 +0100, AbingdonBoy wrote:


Hi All,

I am going to fitting a vacuum tube solar panel for water heating, and
combine this with a solar store (using a plate heat exchanger to supply
mains hot water). i am also in the process of fitting a wood burning
stove with a back boiler, that i plan to link to the thermal store.
With these two systems i should have hot water for a fair amount of the
time, however, there are times when the solar panels are not working and
the wood burning stove is not convient, and the hot water is going to
need a top up. So i plan to run the 'hot' water through a Combi boiler
to 'assist' the hot water. The combi will also run the central heating
system.

My problem is that all of the major boiler manufacturers i have spoken
to say that their systems will not work with a warm/hot input. Does
anyone know who does? I know that it is offered by one company
(Eco-Home?) but i have never heard of them.

You may have meant Eco-Hometec. Andy Hall has a non-combi one of them
and seems content with it.

However, probably, the best way to run things is to allow for the boiler
to heat the store via another
indirect coil. The controls can be set to keep the store up to
the minimum temperature whilst the wood stove and solar will be allowed to
take the store to the maximum allowed temperature. The CH can then be
taken from the store as needed.

No doubt people with more knowledge of stores and banks than me will
refine this scheme.

--
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

"AbingdonBoy" wrote in message
...

Hi All,

I am going to fitting a vacuum tube solar panel for water heating, and
combine this with a solar store (using a plate heat exchanger to supply
mains hot water). i am also in the process of fitting a wood burning
stove with a back boiler, that i plan to link to the thermal store.
With these two systems i should have hot water for a fair amount of the
time, however, there are times when the solar panels are not working and
the wood burning stove is not convient, and the hot water is going to
need a top up. So i plan to run the 'hot' water through a Combi boiler
to 'assist' the hot water. The combi will also run the central heating
system.

My problem is that all of the major boiler manufacturers i have spoken
to say that their systems will not work with a warm/hot input. Does
anyone know who does? I know that it is offered by one company
(Eco-Home?) but i have never heard of them.

Many thanks in advance for any help that you can give...

Have a thermal store/heat bank, that has a coil for solar and one for the
wood burner, or have them direct, and also heated by the boiler. Take the
CH off the thermal store.

On Thu, 20 Oct 2005 19:11:42 +0100, Ed Sirett
wrote:

On Thu, 20 Oct 2005 14:42:25 +0100, AbingdonBoy wrote:


Hi All,

I am going to fitting a vacuum tube solar panel for water heating, and
combine this with a solar store (using a plate heat exchanger to supply
mains hot water). i am also in the process of fitting a wood burning
stove with a back boiler, that i plan to link to the thermal store.
With these two systems i should have hot water for a fair amount of the
time, however, there are times when the solar panels are not working and
the wood burning stove is not convient, and the hot water is going to
need a top up. So i plan to run the 'hot' water through a Combi boiler
to 'assist' the hot water. The combi will also run the central heating
system.

My problem is that all of the major boiler manufacturers i have spoken
to say that their systems will not work with a warm/hot input. Does
anyone know who does? I know that it is offered by one company
(Eco-Home?) but i have never heard of them.

You may have meant Eco-Hometec. Andy Hall has a non-combi one of them
and seems content with it.

They are simply a reseller for a number of German and Dutch
manufacturers.


The boiler in question is the Micromat, made by MHG Heiztechnik (MBO
of division of MAN the engine company).

It's a very well designed and made product, but not cheap.

There are a plethora of controls and monitoring in terms of weather
compensation etc.

One of its big advantages is being able to modulate over a large
range. For example, most models will drop down to 3-4kW and 40
degrees on the flow side.

It can be configured in a lot of different ways. For example, on the
non-combi version, you can have completely separate behaviour for
water heating vs. CH.

I use it to heat the HW in a fast recovery cylinder because it suits
my purposes well - I am not using alternative sources of heat other
than electricity as a backup.

There is an optional analogue sensor for the DHW, and this can be used
to give precise control. I have it configured to heat the cylinder
rapidly, and that's it. It doesn't overshoot on temperature. Equally,
one could use it to maintain a certain store tempoerature.

With a boiler of this type, there is no point in using the thermal
store to run the CH, unless there is another major heat source. Having
the store in the middle effectively defeats the behaviour of the
weather compensation.

Whether the combi version is suitable for heating the HW, prewarmed to
almost the same temperature as for use, I am not sure. It's more
typical to combine using the store.







However, probably, the best way to run things is to allow for the boiler
to heat the store via another
indirect coil. The controls can be set to keep the store up to
the minimum temperature whilst the wood stove and solar will be allowed to
take the store to the maximum allowed temperature. The CH can then be
taken from the store as needed.

No doubt people with more knowledge of stores and banks than me will
refine this scheme.

--

..andy

To email, substitute .nospam with .gl

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

With a boiler of this type, there is no
point in using the thermal
store to run the CH, unless there is another
major heat source.

Matt, if you had a heat bank or thermal store you don't need a boiler like
the MAN. The great thing about thermal stores is that cheap, simple
non-modulating, and potentially more reliable boilers can be used.

Christian McArdle wrote:

I'd run the DHW straight off the heat bank. Use the gas boiler to heat that,
rather than attempting to boost the tank output. Consider running the rads
off the heatbank if the solar is going to provide significant heat.

Ditto. Combi's are intended for flats & small houses, with all the
components in one wall-mounted box. Fine for the installer, but a PITA
to repair/service once the warranty has expired, compared to a plain
system boiler.

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

Christian McArdle wrote:

I'd run the DHW straight off the heat bank. Use the gas boiler to heat
that,
rather than attempting to boost the tank output. Consider running the
rads
off the heatbank if the solar is going to provide significant heat.

Ditto. Combi's are intended for flats & small houses, with all the
components in one wall-mounted box. Fine for the installer, but a PITA
to repair/service once the warranty has expired, compared to a plain
system boiler.

Nonsense.

On Fri, 21 Oct 2005 00:02:42 +0100, "Doctor Drivel"
wrote:


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

With a boiler of this type, there is no
point in using the thermal
store to run the CH, unless there is another
major heat source.

Matt, if you had a heat bank or thermal store you don't need a boiler like
the MAN. The great thing about thermal stores is that cheap, simple
non-modulating, and potentially more reliable boilers can be used.


You had better discuss that with Matt.

As you have argued yourself on many occasions (e.g. in terms of
condensing vs. non-condensing), there is not inherently a difference
in complexity in the sense of a reliability factor between a simple
boiler and a more complex one.

The issue with respect to reliability is design, component and build
quality.


Use of a thermal store is a different matter entirely.


--

..andy

To email, substitute .nospam with .gl

In article .com,
Aidan writes

Christian McArdle wrote:

I'd run the DHW straight off the heat bank. Use the gas boiler to heat that,
rather than attempting to boost the tank output. Consider running the rads
off the heatbank if the solar is going to provide significant heat.

Ditto. Combi's are intended for flats & small houses, with all the
components in one wall-mounted box. Fine for the installer, but a PITA
to repair/service once the warranty has expired, compared to a plain
system boiler.

Having been subjected to daytime television yesterday... I did end up
watching one of the build your own house type programs where they had
reached the point of installing the heating system, they summed up the
discussion by concluding that combi's are suitable for smaller houses
but larger properties are better with stored hot water systems. I saw it
on television so it must be true.
--
David

AbingdonBoy wrote:

My problem is that all of the major boiler manufacturers i have spoken
to say that their systems will not work with a warm/hot input. Does
anyone know who does? I know that it is offered by one company
(Eco-Home?) but i have never heard of them.

I have the Eco-Hometec EC36S (I think)
It's actually made by MAN you know, the German company that makes
Lorries and stuff.

The plumber that fitted it was extermely impressed with it's features
and design etc.

It measures the temperature of the inlet water and adjusts heat input as
required to bring water to Rqd. temp.

Also has outdoor temp sensor as standard which regulates C/H water based
on outside temp.

Prolly twice the price of most boilers but very pleased with it so far.

HTH

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

"Andy Hall" aka Matt wrote in message
...
On Fri, 21 Oct 2005 00:02:42 +0100, "Doctor Drivel"
wrote:


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

With a boiler of this type, there is no
point in using the thermal
store to run the CH, unless there is another
major heat source.

Matt, if you had a heat bank or thermal store you don't need a boiler
like
the MAN. The great thing about thermal stores is that cheap, simple
non-modulating, and potentially more reliable boilers can be used.


You had better discuss that with Matt.

Matt, I am discussing it with Matt.

As you have argued yourself on many occasions (e.g. in terms of
condensing vs. non-condensing), there is not inherently a difference
in complexity in the sense of a reliability factor between a simple
boiler and a more complex one.

Properly designed condensing boilers are no more complex than non-condensing
boiler - you obviously don't know this Matt.

The issue with respect to reliability is design,

Yes.

component

The less the better. Less = more reliable.

and build
quality.

Yes.

Two out three Matt. Not bad.

Use of a thermal store is a different matter entirely.

When using a thermal store. Again...
"Matt, if you had a heat bank or thermal store you don't need a boiler like
the MAN. The great thing about thermal stores is that cheap, simple,
non-modulating, and potentially more reliable boilers can be used."

"David" wrote in message
...
In article .com,
Aidan writes

Christian McArdle wrote:

I'd run the DHW straight off the heat bank. Use the gas boiler to heat
that,
rather than attempting to boost the tank output. Consider running the
rads
off the heatbank if the solar is going to provide significant heat.

Ditto. Combi's are intended for flats & small houses, with all the
components in one wall-mounted box. Fine for the installer, but a PITA
to repair/service once the warranty has expired, compared to a plain
system boiler.

Having been subjected to daytime television yesterday... I did end up
watching one of the build your own house type programs where they had
reached the point of installing the heating system, they summed up the
discussion by concluding that combi's are suitable for smaller houses
but larger properties are better with stored hot water systems. I saw it
on television so it must be true.

Bertie, you must believe everything you see on TV.

David wrote:

Having been subjected to daytime television yesterday... I did end up
watching one of the build your own house type programs where they had
reached the point of installing the heating system, they summed up the
discussion by concluding that combi's are suitable for smaller houses
but larger properties are better with stored hot water systems. I saw it
on television so it must be true.

Nooo you are misguided.
It only becomes genuinely true once you read it on the interweb!


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

Andy Hall wrote:

Whether the combi version is suitable for heating the HW, prewarmed to
almost the same temperature as for use, I am not sure. It's more
typical to combine using the store.

The Combi works exactly the same way as your WRT sensing water
temperature going in.


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

In article ws.net,
Doctor Drivel writes

"David" wrote in message
.. .
In article .com,
Aidan writes

Christian McArdle wrote:

I'd run the DHW straight off the heat bank. Use the gas boiler to heat
that,
rather than attempting to boost the tank output. Consider running the
rads
off the heatbank if the solar is going to provide significant heat.

Ditto. Combi's are intended for flats & small houses, with all the
components in one wall-mounted box. Fine for the installer, but a PITA
to repair/service once the warranty has expired, compared to a plain
system boiler.

Having been subjected to daytime television yesterday... I did end up
watching one of the build your own house type programs where they had
reached the point of installing the heating system, they summed up the
discussion by concluding that combi's are suitable for smaller houses
but larger properties are better with stored hot water systems. I saw it
on television so it must be true.

Bertie, you must believe everything you see on TV.

That's what I said John, do try to keep up
--
David

"David" wrote in message
...
In article ws.net,
Doctor Drivel writes

"David" wrote in message
.. .
In article .com,
Aidan writes

Christian McArdle wrote:

I'd run the DHW straight off the heat bank. Use the gas boiler to
heat
that,
rather than attempting to boost the tank output. Consider running
the
rads
off the heatbank if the solar is going to provide significant heat.

Ditto. Combi's are intended for flats & small houses, with all the
components in one wall-mounted box. Fine for the installer, but a PITA
to repair/service once the warranty has expired, compared to a plain
system boiler.

Having been subjected to daytime television yesterday... I did end up
watching one of the build your own house type programs where they had
reached the point of installing the heating system, they summed up the
discussion by concluding that combi's are suitable for smaller houses
but larger properties are better with stored hot water systems. I saw
it
on television so it must be true.

Bertie, you must believe everything you see on TV.

That's what I said John, do try to keep up

Bertie, you need reassuring that all is right on the telly.

"Pet @ www.gymratz.co.uk ;¬)" wrote in message
news
David wrote:

Having been subjected to daytime television yesterday... I did end up
watching one of the build your own house type programs where they had
reached the point of installing the heating system, they summed up the
discussion by concluding that combi's are suitable for smaller houses
but larger properties are better with stored hot water systems. I saw it
on television so it must be true.

Nooo you are misguided.
It only becomes genuinely true once you read it on the interweb!

Nonsense, only when in the Sun.