I am trying to sort out my badly installed woodburner with back boiler
plumbed incorrectly.

Fitting a Dunsley Baker Neutraliser would be very difficult, and as an
alternative I am exploring the use of normally-open motorised valves.

Is there such a thing as a non return valve available for 28mm copper
pipework? I think this would help get a better result. If so, could
someone post a link and/or the proper name for me?

Keith

On 27 July, 19:39, Keefiedee wrote:
I am trying to sort out my badly installed woodburner with back boiler
plumbed incorrectly.

Fitting a Dunsley Baker Neutraliser would be very difficult, and as an
alternative I am exploring the use of normally-open motorised valves.

Is there such a thing as a non return valve available for 28mm copper
pipework? *I think this would help get a better result. *If so, could
someone post a link and/or the proper name for me?

Keith

Yes one version is mentioned in the instructions for an Aga/Rayburn,
which has a particularly low pressure to open requirement. From memory
it was called a featherweight check valve.
Keep in mind the heat input from a solid fuel fire and what will
happen if there is a power cut for whatever reason. Gravity
circulation to an adequate heat dump is a basic essential to deal with
this eventuality

On 27 July, 19:39, Keefiedee wrote:
I am trying to sort out my badly installed woodburner with back boiler
plumbed incorrectly.

What's the problem, is there another boiler or a pump in the same
heating system?

Is there such a thing as a non return valve available for 28mm copper
pipework? *I think this would help get a better result. *If so, could
someone post a link and/or the proper name for me?

Yes, there are swing-check (hinged flap, closes under it's own weight,
observe fitting orientation) and spring-check (spring assisted, can
usually be adjusted) types. I'm dubious that they'd fix the problem,
but that depends on what the problem is.
There shouldn't be any valves in the pipes between the boiler, open
vent, heat dump radiator, cold feed.

On Jul 27, 9:53*pm, Onetap wrote:


What's the problem, is there another boiler or a pump in the same
heating system?

The problem is that the woodburner back boiler feeds and returns have
been simply plumbed into the main central S plan heating arrangement
with plain T joints - at some considerable distance from the oil
boiler. The result is of course that the oil boiler ends up heating
the water in the back boiler (along with long runs of 28mm pipework)
as well as the rest of the house . I discovered this problem when
balancing the radiators after replacing several of them using one of
those clever infrared temperature thingys. The input temp at the
radiators was 5 degree C or more less than it should be.

I solved the problem initially using simple ball valves on the
woodburner flows and returns and remembering to open them when I lit
the woodburner - highly unsatisfactory (and potentially dangerous). I
had a heating engineer round about fitting a Dursley Neutraliser. He
seemed to know his stuff but couldn't really work out a way to sort it
without considerable expense.

The point is that we never need to use the oil boiler and woodburner
together. Also the woodburner is rated at a much lower output than
the oil boiler, and procuring and lugging into the room all the wood
needed to keep the woodburner going at full tilt simply does not
really fit in with our lifestyle. It isn't really necessary anyway -
it is a big house, but having the oil boiler running for up to 4 hours
in the morning, with perhaps the occasional topup during the day, is
adequate to keep it reasonably warm. The woodburner is in the room we
sit in at night, and a fairly small fire is enough for our needs.

The only fail-safe answer I can come up with is using 4 "normally
open" motorised valves, wired so they close when the boiler comes on,
but these cost a minimum of £65 each for 28mm valves as far as I can
see. So I was toying with the idea of just fitting two on the central
heating side of the woodburner pipework and somehow working out if I
could make do with non-return valves on the HW side - if such things
existed - hence my question.

At least I know they do exist now, I just haven't quite yet got my
head round where I should fit them and whether they would help.

Keith

We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember Keefiedee
saying something like:

The only fail-safe answer I can come up with is using 4 "normally
open" motorised valves, wired so they close when the boiler comes on,
but these cost a minimum of £65 each for 28mm valves as far as I can
see. So I was toying with the idea of just fitting two on the central
heating side of the woodburner pipework and somehow working out if I
could make do with non-return valves on the HW side - if such things
existed - hence my question.

You don't need two of anything. Just the one would do, but as a general
rule, nothing that could stick closed should be put into a gravity loop.
It works, that I do know - I've come across it, but I wouldn't do it,
just in case.
Have you seen the results of a steam explosion in a house?

On Wed, 28 Jul 2010 07:26:19 +0100, Grimly Curmudgeon wrote:

You don't need two of anything. Just the one would do,

I can't get me 'ed around the requirement for four and then dragging
the HW circuit into the equation. I guess there could be a second
loop from the wood burner to a coil in the HW cylinder...

As for spring valves I doubt very much that gravity would have enough
'umph to open them. A biased open(*) flap valve that closes when the
pump for the oil boiler tries to cause flow through the woodburner
loop might work.

But still doesn't avoid the problem of no flow through the
woodburner. At least with only one valve the woddburner boiler would
still be open but could still boil, Maybe adding another vent
vertically close to the woodburner with a whistle on the end... B-)

(*) By orientating it so gravity makes it open.

--
Cheers
Dave.

On 28 July, 09:06, "Dave Liquorice"
wrote:
On Wed, 28 Jul 2010 07:26:19 +0100, Grimly Curmudgeon wrote:
You don't need two of anything. Just the one would do,

I can't get me 'ed around the requirement for four and then dragging
the HW circuit into the equation. I guess there could be a second
loop from the wood burner to a coil in the HW cylinder...

As for spring valves I doubt very much that gravity would have enough
'umph to open them. A biased open(*) flap valve that closes when the
pump for the oil boiler tries to cause flow through the woodburner
loop might work.

But still doesn't avoid the problem of no flow through the
woodburner. At least with only one valve the woddburner boiler would
still be open but could still boil, Maybe adding another vent
vertically close to the woodburner with a whistle on the end... B-)

(*) By orientating it so gravity makes it open.

--
Cheers
Dave.

Our woodburner in a similar set up has a motorised valve and pump on
the pipe that links the woodburner's boiler to the main heating loop
and these are controlled by a thermostat on the flow pipe by the
burner. For safety reasons that are two radiators that are directly
linked to the woodburner to dissipate any excess heat.

Jonathan

On Jul 28, 9:06*am, "Dave Liquorice"
wrote:

I can't get me 'ed around the requirement for four and then dragging
the HW circuit into the equation. I guess there could be a second
loop from the wood burner to a coil in the HW cylinder...

In both boilers the CH and HW circuits are connected - i.e. each have
two loops from the heating chamber - thus four pipes. My concern was
that it might be possible for the return flow from the radiators,
which is connected by a T-junction to the return flow of the
woodburner, to not just go back to the oil boiler but also to go
through the woodburner CH return, through the woodburner boiler and
then through the woodburner HW return and generally lose heat where it
shouldn't before finding its way back to the oil boiler return.

I imagine one could argue that the suction effect of the CH pump is
likely to draw the water flow back towards the oil boiler and so it's
not likely to flow towards the woodburner CH return, but a little
experiment I have just done - switching on the oil boiler and closing
the feeds but not the returns to the woodburner for a short while -
soon resulted in a small, but significant increase in the temperature
of the woodburner CH return. So as far as I can see, 4 normally open
valves would be needed to completely stop any possible flow throuhg
the woodburner boiler.

I assume standard normally open motorised valves cannot stick closed
and are normally used in solid fuel systems and fail safe in the event
of a power failure.

And to reassure the guy concerned about a steam explosion, although
the plumbing of the woodburner has generally been bodged, they did at
least fit a steam release valve!!!

Keith

On Jul 28, 9:06*am, "Dave Liquorice"
wrote:

I can't get me 'ed around the requirement for four and then dragging
the HW circuit into the equation. I guess there could be a second
loop from the wood burner to a coil in the HW cylinder...

In both boilers the CH and HW circuits are connected - i.e. each have
two loops from the heating chamber - thus four pipes. My concern was
that it might be possible for the return flow from the radiators,
which is connected by a T-junction to the return flow of the
woodburner, to not just go back to the oil boiler but also to go
through the woodburner CH return, through the woodburner boiler and
then through the woodburner HW return and generally lose heat where it
shouldn't before finding its way back to the oil boiler return.

I imagine one could argue that the suction effect of the CH pump is
likely to draw the water flow back towards the oil boiler and so it's
not likely to flow towards the woodburner CH return, but a little
experiment I have just done - switching on the oil boiler and closing
the feeds but not the returns to the woodburner for a short while -
soon resulted in a small, but significant increase in the temperature
of the woodburner CH return. So as far as I can see, 4 normally open
valves would be needed to completely stop any possible flow throuhg
the woodburner boiler.

I assume standard normally open motorised valves cannot stick closed
and are normally used in solid fuel systems and fail safe in the event
of a power failure.

And to reassure the guy concerned about a steam explosion, although
the plumbing of the woodburner has generally been bodged, they did at
least fit a steam release valve!!!

Keith

The problem is that the woodburner back boiler feeds and returns have
been simply plumbed into the main central S plan heating arrangement
with plain T joints...

Isn't this an application for injector tee's?

http://shop.ebay.co.uk/i.html?_nkw=i...286.m270.l1313

If you want use a swing check valves, BES has a good range:

http://www.bes.co.uk/ (search for "swing check valve")

On Wed, 28 Jul 2010 04:34:01 -0700 (PDT), wrote:

Isn't this an application for injector tee's?

http://www.injector-tee.co.uk

You can see the construction but it doesn't explain in detail how it
works... I'd have thought the flow through the injector would tend to
draw water from the branch and thus through that loop.

--
Cheers
Dave.

"Dave Liquorice" wrote in message
ll.co.uk...
On Wed, 28 Jul 2010 04:34:01 -0700 (PDT), wrote:

Isn't this an application for injector tee's?

http://www.injector-tee.co.uk

You can see the construction but it doesn't explain in detail how it
works... I'd have thought the flow through the injector would tend to
draw water from the branch and thus through that loop.

--
Cheers
Dave.




It looks as if it could be venturi effect.
http://www.google.co.uk/search?num=5...effect&spell=1

Baz