The oil boiler is an ageing 100,000 odd BTU thing for both hot water and heating,
and I am thinking of changing it. The Aga also heats the water in the summer.

First quote said "the DHW cylinder also needed changing" - I can't understand why.
Is it these new regs that say when you change the boiler, the cylinder also has to be
changed ? Or is he trying to take me for a ride ? Do I have to change the Aga as well ?
Should I get a new car as well ?

The cylinder is only a few years old and showing no signs of failing, but when it does
it will be replaced with the current spec item conforming to the new regs - fair enough!

I get the feeling the job is being glossed up to extract more money by doing
unnecessary work.

Can anyone advise please ?

Thank you,

Nick

On Mon, 6 Oct 2003 08:15:19 +0100, "froggers"
wrote:

The oil boiler is an ageing 100,000 odd BTU thing for both hot water and heating,
and I am thinking of changing it. The Aga also heats the water in the summer.

First quote said "the DHW cylinder also needed changing" - I can't understand why.
Is it these new regs that say when you change the boiler, the cylinder also has to be
changed ?

Not as far as I have read in the relevant parts of the building
regulations (Part J and Part L1). Part J deals with installation of
fuel burning appliances, while Part L1 is about domestic energy
efficiency. You can find Approved Documents (which are guidelines to
the law) on the ODPM web site.

It would be useful to know how this is all hooked up since you have
two heat sources for the DHW. Can you provide some more detail?

It is possible that the specific hookup is not suitable for a new
boiler, but I can't think of a generic reason why the cylinder should
require replacement.

The only things that immediately occur is if the cylinder is direct
rather than having a heating coil - this is generally not a good idea
anyway - or if the proposed boiler has a high heat output to hot water
and requires a high transfer rate of the coil as in a fast recovery
cylinder. A 30kW boiler is not especially high powered although if
the coil is particularly poor this could be an issue of boiler cycling
because the boiler is producing heat much faster than the cylinder can
accept it.

I would suggest getting the technical documentation or installation
guide for the proposed boiler, then ask the installer back and ask him
to explain his reasons. Also, get another quote or two anyway.

Or is he trying to take me for a ride ? Do I have to change the Aga as well ?

Definitely not. How on earth would you make your toast?

If you are doing a major plumbing exercise, it may be worth taking the
Aga out of the work of heating the cylinder. Its rate of heat
production to the hot water is pretty low so I am not sure that it
really adds any value if you have a thermostatically controlled main
boiler. However do call Aga-Rayburn's technical department and ask
about decommissioning if you want to do this. AFAIK, it is simply a
case of disconnecting, rather than needing to disassemble and swap the
water jacket components.


Should I get a new car as well ?

Land Rovers are good.


The cylinder is only a few years old and showing no signs of failing, but when it does
it will be replaced with the current spec item conforming to the new regs - fair enough!

I get the feeling the job is being glossed up to extract more money by doing
unnecessary work.

Could be.


Can anyone advise please ?

Thank you,

Nick


..andy

To email, substitute .nospam with .gl

froggers wrote:

The oil boiler is an ageing 100,000 odd BTU thing for both hot water and heating,
and I am thinking of changing it. The Aga also heats the water in the summer.

First quote said "the DHW cylinder also needed changing" - I can't understand why.
Is it these new regs that say when you change the boiler, the cylinder also has to be
changed ? Or is he trying to take me for a ride ? Do I have to change the Aga as well ?
Should I get a new car as well ?


Maybe he wasnt you to use a pressurised system.

Its not a good idea BTW to simply disconnect the Aga hot water circuit.
I think you need to talk to aga about that - frankly if the gravity fed
pipework is in placve, and it works, I'd leave it generating hot water.
My aga costs an estmated £300 a year to run pluis servicing if left on
through the summer, and you might as well see some benfit.



The cylinder is only a few years old and showing no signs of failing, but when it does
it will be replaced with the current spec item conforming to the new regs - fair enough!

I get the feeling the job is being glossed up to extract more money by doing
unnecessary work.


I'd ask the plumber for a clear exaplantion of WHY a new cylinder is
needed. Then post it here. If it makes sense, well fine. If it doesn't,
then get another plumber.

I can think of reasons - maybe you have a gravity fed system and pumped
is indicated etc.

There are several heating experts here. Why not get the plumbers opinion
and compare with others thoughts?



Can anyone advise please ?

Thank you,

Nick

First quote said "the DHW cylinder also needed changing" - I can't
understand why.

It may be because the complications of the Aga and old gravity circulated
boiler might make installing a modern boiler impossible. It is likely that a
modern boiler and an Aga have very different ideas of what a primary circuit
should look like.

If so, this is one type of system that would seriously benefit from a heat
bank rather than traditional cylinder. They allow multiple heat sources to
be used very simply, including a gravity circulated direct system (like what
the Aga might like) and a pressurised sealed indirect coil (just what the
modern boiler ordered). As an extra benefit, they also supply lashings of
mains pressure hot water. (If your mains isn't good enough, you could always
feed it from a cold cistern instead).

Christian.