Trying to get around to creating a short-list of potential boilers. Need to
arrange for flue to go from ground floor through existing chimney to
terminal at chimney pot height.

Am I right in assuming that a twin tube system give more scope for a longer
flue than a concentric arrangement? If so, why? (Then we need to consider if
a twin pipe would fit up the chimney) Any thoughts on boilers - 4 bedrooms -
2 bathrooms (not mine)

On Aug 16, 9:25 pm, "John" wrote:
Trying to get around to creating a short-list of potential boilers. Need to
arrange for flue to go from ground floor through existing chimney to
terminal at chimney pot height.

Am I right in assuming that a twin tube system give more scope for a longer
flue than a concentric arrangement? If so, why? (Then we need to consider if
a twin pipe would fit up the chimney)

Nobody's replied, so I'll offer my uneducated guesses.

Presumably there would be more friction in a concentric arrangement
than in a twin tube setup, making the maximum run shorter?

On Thu, 16 Aug 2007 20:25:53 +0000, John wrote:

Trying to get around to creating a short-list of potential boilers. Need to
arrange for flue to go from ground floor through existing chimney to
terminal at chimney pot height.

Am I right in assuming that a twin tube system give more scope for a longer
flue than a concentric arrangement?

Probably not

(Then we need to consider if a twin pipe would fit up the chimney)

You ought also consider that it is, according to CORGI's 'Gas Installaer'
magazine, a requirement of the Gas Safety Installation and Use Regulations
http://www.opsi.gov.uk/si/si1998/19982451.htm
that flues should be accesible for inspection prior to initial
comissioning of the appliance and during routine servicing or maintenance
of the appliance.

(I can't see that in the regs myself unless one interprets section 28
"No person shall install a gas appliance except in such a manner that
it is readily accessible for operation, inspection and maintenance" to
include flues within the meaning of 'appliance', which is not explicit in
section 2 "General interpretation and application")


--
John Stumbles

Bitwise, byte foolish

On Fri, 17 Aug 2007 12:34:30 +0000, John Stumbles wrote:

On Thu, 16 Aug 2007 20:25:53 +0000, John wrote:

Trying to get around to creating a short-list of potential boilers. Need to
arrange for flue to go from ground floor through existing chimney to
terminal at chimney pot height.

Am I right in assuming that a twin tube system give more scope for a longer
flue than a concentric arrangement?

Probably not

(Then we need to consider if a twin pipe would fit up the chimney)

You ought also consider that it is, according to CORGI's 'Gas Installaer'
magazine, a requirement of the Gas Safety Installation and Use Regulations
http://www.opsi.gov.uk/si/si1998/19982451.htm
that flues should be accesible for inspection prior to initial
comissioning of the appliance and during routine servicing or maintenance
of the appliance.

(I can't see that in the regs myself unless one interprets section 28
"No person shall install a gas appliance except in such a manner that
it is readily accessible for operation, inspection and maintenance" to
include flues within the meaning of 'appliance', which is not explicit in
section 2 "General interpretation and application")


Sounds to me that the OP might not be fully aware of the details of
how modern boiler systems are intended to be used.

Twin pipe is generally more versatile (and cheaper) for the more awkward
arrangements, concentric pipe is more common and it more usual in the vast
majority of installations.

There is (IME at least) many other options that are better before reusing
a brick chimney as a pipe work duct.






--
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 message
...
On Fri, 17 Aug 2007 12:34:30 +0000, John Stumbles wrote:

On Thu, 16 Aug 2007 20:25:53 +0000, John wrote:

Trying to get around to creating a short-list of potential boilers. Need
to
arrange for flue to go from ground floor through existing chimney to
terminal at chimney pot height.

Am I right in assuming that a twin tube system give more scope for a
longer
flue than a concentric arrangement?

Probably not

(Then we need to consider if a twin pipe would fit up the chimney)

You ought also consider that it is, according to CORGI's 'Gas Installaer'
magazine, a requirement of the Gas Safety Installation and Use
Regulations
http://www.opsi.gov.uk/si/si1998/19982451.htm
that flues should be accesible for inspection prior to initial
comissioning of the appliance and during routine servicing or maintenance
of the appliance.

(I can't see that in the regs myself unless one interprets section 28
"No person shall install a gas appliance except in such a manner that
it is readily accessible for operation, inspection and maintenance" to
include flues within the meaning of 'appliance', which is not explicit in
section 2 "General interpretation and application")


Sounds to me that the OP might not be fully aware of the details of
how modern boiler systems are intended to be used.

Twin pipe is generally more versatile (and cheaper) for the more awkward
arrangements, concentric pipe is more common and it more usual in the vast
majority of installations.

There is (IME at least) many other options that are better before reusing
a brick chimney as a pipe work duct.






--
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

The house owner is hoping to make use of the current boiler location
(kitchen - internal wall - with brick flue to chimney.) although he realises
that considerable work will be required to change the pipework, etc. an
alternative may be to use the upstairs airing cupboard (where cylinder is
located). Much depends on the routing options for pipes. The house is well
decorated, tiles, wooden floors, etc. I am merely discussing over a pint or
two the various options before he gets a Corgi guy in who we feel may have a
narrow bias and will not have an intimate knowledge of the house layout for
considering pipe runs.
The solution may not be a combi.

OP

John

On Sun, 19 Aug 2007 08:48:13 +0000, John wrote:

"Ed Sirett" wrote in message
...
On Fri, 17 Aug 2007 12:34:30 +0000, John Stumbles wrote:

On Thu, 16 Aug 2007 20:25:53 +0000, John wrote:

Trying to get around to creating a short-list of potential boilers. Need
to
arrange for flue to go from ground floor through existing chimney to
terminal at chimney pot height.

Am I right in assuming that a twin tube system give more scope for a
longer
flue than a concentric arrangement?

Probably not

(Then we need to consider if a twin pipe would fit up the chimney)

You ought also consider that it is, according to CORGI's 'Gas Installaer'
magazine, a requirement of the Gas Safety Installation and Use
Regulations
http://www.opsi.gov.uk/si/si1998/19982451.htm
that flues should be accesible for inspection prior to initial
comissioning of the appliance and during routine servicing or maintenance
of the appliance.

(I can't see that in the regs myself unless one interprets section 28
"No person shall install a gas appliance except in such a manner that
it is readily accessible for operation, inspection and maintenance" to
include flues within the meaning of 'appliance', which is not explicit in
section 2 "General interpretation and application")


Sounds to me that the OP might not be fully aware of the details of
how modern boiler systems are intended to be used.

Twin pipe is generally more versatile (and cheaper) for the more awkward
arrangements, concentric pipe is more common and it more usual in the vast
majority of installations.

There is (IME at least) many other options that are better before reusing
a brick chimney as a pipe work duct.






--
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

The house owner is hoping to make use of the current boiler location
(kitchen - internal wall - with brick flue to chimney.) although he realises
that considerable work will be required to change the pipework, etc. an
alternative may be to use the upstairs airing cupboard (where cylinder is
located). Much depends on the routing options for pipes. The house is well
decorated, tiles, wooden floors, etc. I am merely discussing over a pint or
two the various options before he gets a Corgi guy in who we feel may have a
narrow bias and will not have an intimate knowledge of the house layout for
considering pipe runs.
The solution may not be a combi.

The trouble with chimneys is
1) Access arrangements
2) They usually aren't straight.

This makes there initial attractiveness wear off pretty quickly IME.




--
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