Hi, Does anyone know what's inside one of these?

It's a bit of kit to link up two boiler systems. My dad's doing a self
build and he's going to need one but is curious as to how they work.

Thanks x

"bell" wrote in message
om...

Hi, Does anyone know what's inside one of these?

nothing. it is empty, just a neutral point.

It's a bit of kit to link up two boiler systems. My dad's doing a self
build and he's going to need one but is curious as to how they work.

He needs one? On a selfbuild he is better off using a thermal store/heat
bank, which also acts as a neutral point and gives a hell of a lot more,like
mains pressure hot water, than the Dunsley.

On 22 Oct 2004 05:36:12 -0700, (bell) wrote:

Hi, Does anyone know what's inside one of these?

It's a bit of kit to link up two boiler systems. My dad's doing a self
build and he's going to need one but is curious as to how they work.

Thanks x

Google for it, there's quite a bit, including diagrams. Might help
you.

On 22 Oct 2004 05:36:12 -0700, (bell) wrote:

Hi, Does anyone know what's inside one of these?

It's a bit of kit to link up two boiler systems. My dad's doing a self
build and he's going to need one but is curious as to how they work.

Thanks x


There is NOTING inside them.

I had one, I was not overly impressed with it, in fact I have now
taken it out.

Rick

"IMM" wrote in message
...

"bell" wrote in message
om...

Hi, Does anyone know what's inside one of these?

nothing. it is empty, just a neutral point.

It's a bit of kit to link up two boiler systems. My dad's doing a self
build and he's going to need one but is curious as to how they work.

He needs one? On a selfbuild he is better off using a thermal store/heat
bank, which also acts as a neutral point and gives a hell of a lot
more,like
mains pressure hot water, than the Dunsley.

Give me his scheme and I will suggest, if better of course, an alternative.

It's a bit of kit to link up two boiler systems. My dad's doing a self
build and he's going to need one but is curious as to how they work.

It is effectively a direct heat bank which is too small for useful storage.
Basically just a can with lots of pipes coming out of it. Nothing magical
about it at all, but just a simple elegant solution.

Any heat sources pump (or gravity feed) into the can. Any heat sinks pump
(or gravity feed) from the can. Simple and effective. It enables several
heat sinks or sources to be used simultaneously without each appliance
interfering with the other's pumped or gravity circulation.

For a new system, you might want to consider a direct heatbank instead. This
is the same thing, but with a huge tank, rather than a little can, allowing
for useful storage, which reduces short cycling inefficiency. Then your
solid fuel appliance and gas/oil boiler can both power radiators and even
provide lashings of mains pressure hot water through a plate heat exchanger.
You can also have a hybrid system with an additional indirect coil, which
allows sealed pressurised operation on the oil/gas boiler.

You lose a little in efficiency from a condensing boiler, as the flow
temperature has to be higher, but gain on eliminating short cycling and
using otherwise wasted heat from a solid fuel appliance (or hydronic solar,
or any other heat sources you install).

Christian.

Rick Dipper wrote in message . ..
On 22 Oct 2004 05:36:12 -0700, (bell) wrote:

Hi, Does anyone know what's inside one of these?

It's a bit of kit to link up two boiler systems. My dad's doing a self
build and he's going to need one but is curious as to how they work.

Thanks x


There is NOTING inside them.

I had one, I was not overly impressed with it, in fact I have now
taken it out.

Rick

No point in describing it any further - it's all been said, apart
from the fact that in the system I'm using it works spendidly. I've
an oil fired boiler pumping into it and a log stove gravity feed into
it. Trying to remember the output configuration without diving into a
folder - the cylinder has to be gravity fed but is shut of with a fail
safe valve when the CH pump is on. A bit of home grown electronics
controls the system such that the oil burner is shut down if the log
stove is hot.

Plumbing it in is an keen-amateur job - no self respecting plumber
would take it on unless the customer had deeeeep pockets. In a
confined space it looks very neat but plumbing wise a 'challenge'.

I'm assuming that of the two heat sources the OP has, one needs to be
gravity run as I have. I would be interested to know how the heatbank
arrangement can be configured for this; I'm in the market for a design
for such a set-up as I need to overcome low pressure in the HW system
and am not a fan of pumps. I've been following the various threads on
the subject but have had difficulty understanding some of the piping
diagrams that have been posted.

Having said all that I went to visit a friend the other day who lives
in a stately pile where he has built a system of 2 domestic gas
boilers working in some astonishing configuration involving homemade
heat exchangers, etc; the pipework would do the boiler room of small
steam ship a run for it's money.

Rob

Rob

On Fri, 22 Oct 2004 15:51:46 +0100, "Christian McArdle"
wrote:

I had one, I was not overly impressed with it, in fact I have now
taken it out.

What did you replace it with?

Christian.


I had mine configured with 2 boilers, gas & wood.

I replaced it with some simple electronice, when the wood fire is hot
the gas boiler switches off, and all the zone valves open. When the
wood fire is cold, the zone value closes it off.

So the two flows from the boliers are simply joined together, and the
hot water feeds into the heating circuits. Only one bolier ever
operates at a time.

I found problems with then Dunsley were :-

A pain in the butt to fit into a reasonably small space.
A pain in the butt to fitt, if you got a leek, you had to
take half the plumbing apart to get a spanner anywhere neer.
Totally impossible to insulate

I am not a profesionall plumber, maybe I would have been happier if
sombody else had done the thing, so I could not critisie my own work.


Rick

On Sun, 24 Oct 2004 10:30:05 GMT, Rick Dipper wrote:

I replaced it with some simple electronice, when the wood fire is
hot the gas boiler switches off, and all the zone valves open. When
the wood fire is cold, the zone value closes it off.

What is the state of the zone valves without power?
Is the gas boiler isolated when the wood fire is hot or does hot water
circulate through it?

--
Cheers
Dave. pam is missing e-mail

I replaced it with some simple electronice, when the wood fire is hot
the gas boiler switches off, and all the zone valves open. When the
wood fire is cold, the zone value closes it off.

The problem is that in an electrical or zone valve failure, the system may
explode. Are you sure that in the event of valve or electrical failure that:

(a) There is a direct unvalved vent path from both appliances to the
outside.
(b) There is a direct unvalved water feed path from the header tank to the
appliances that doesn't share with the vent path.
(c) For any solid fuel appliances, there is a direct unvalved flow path from
flow to return to dump unwanted heat.

Christian.

I'm assuming that of the two heat sources the OP has, one needs to be
gravity run as I have. I would be interested to know how the heatbank
arrangement can be configured for this;

The heatbank is just a huge Dunsley Neutraliser. It is plumbed in the same
way. The only differences are additions.

(1) A pumped plate heat exchanger loop to provide mains pressure hot water.
(2) An indirect coil to allow modern sealed pressurised boilers to be used.
Gravity fed (or circulated) appliances go directly to the heatbank, not
through the indirect coil.
(3) An immersion heater (or 2) for electrical backup.

Christian.

"Christian McArdle" wrote in message . net...
I'm assuming that of the two heat sources the OP has, one needs to be
gravity run as I have. I would be interested to know how the heatbank
arrangement can be configured for this;

The heatbank is just a huge Dunsley Neutraliser. It is plumbed in the same
way. The only differences are additions.

(1) A pumped plate heat exchanger loop to provide mains pressure hot water.
(2) An indirect coil to allow modern sealed pressurised boilers to be used.
Gravity fed (or circulated) appliances go directly to the heatbank, not
through the indirect coil.
(3) An immersion heater (or 2) for electrical backup.

Christian.

Thanks for that Christian - that makes it all nicely fall into place
though I'm not sure whther I'm confused or not by the 'sealed
pressurised boiler' bit. The oil burner I have is some 12 years old -
is that modern - there is no vent from it.

Rob

though I'm not sure whther I'm confused or not by the 'sealed
pressurised boiler' bit. The oil burner I have is some 12 years old -
is that modern - there is no vent from it.

Sounds like it, if there is really no vent. That can use the indirect coil.
Is there a pressure gauge? Do you refill the boiler using a tap, manually
referring to the pressure gauge, or is it filled through a little tank in
the loft?

Christian.