In article ,
Cameron wrote:
The question - Assuming all the boilers are of a similar efficiency, is
there an efficiency advantage of a using either a combi boiler, or an
open vented boiler or a system boiler?

Your real choice is between combi, combi with some storage, and pure
storage. Which hot water system would suit you best depends on many
factors.

--
*Organized Crime Is Alive And Well; It's Called Auto Insurance. *

Dave Plowman London SW
To e-mail, change noise into sound.

Hi
Trying to decide on a new boiler system!

The question - Assuming all the boilers are of a similar efficiency, is there an efficiency advantage of a using either a combi boiler, or an open vented boiler or a system boiler?

Although an existing system Im not bothered about the work load! or to some extent the additional fitting requires

Cameron

On Sun, 07 May 2006 14:21:09 +0100, Cameron wrote:


Hi
Trying to decide on a new boiler system!

The question - Assuming all the boilers are of a similar efficiency, is
there an efficiency advantage of a using either a combi boiler, or an
open vented boiler or a system boiler?

Although an existing system Im not bothered about the work load! or to
some extent the additional fitting requires

For this question we have a FAQ - see boiler choice below.

--
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 question - Assuming all the boilers are of a similar efficiency, is
there an efficiency advantage of a using either a combi boiler, or an
open vented boiler or a system boiler?

An directly comparable instantaneously combi will be more thermodynamically
efficient in the provision of hot water than a storage system. Whether it
will meet the household needs is another matter.

A sealed system might be more efficient than an open vented one, as open
vented ones frequently go wrong in a way that reduces energy efficiency.

Christian.

In article ,
Christian McArdle wrote:
A sealed system might be more efficient than an open vented one, as open
vented ones frequently go wrong in a way that reduces energy efficiency.

Really? Think if you did a straw poll on here of previous posts you'd find
far more about faulty pressurised systems.

--
*Why are a wise man and a wise guy opposites?

Dave Plowman London SW
To e-mail, change noise into sound.

In article .uk,
Ed Sirett wrote:
Really? Think if you did a straw poll on here of previous posts you'd find
far more about faulty pressurised systems.

On balance I think sealed systems are to be preferred.

Ok.

They have one major weakness which is the expansion vessel which is
compounded by many user's refusal/ignorance to attend to this problem
when it arises , and some professionals tendency to fix symptoms (power
flush) rather than the cause (replace the expansion vessel).

When an open vented system is wrongly installed then the problems are
far far worse,

The answer to that is to install it correctly. It's hardly rocket science.

a significant proportion of systems are incorrect. Once
the air is out and they are working they there are a number of fairly
minor problems, (sticking float valve, limescale plug at entry to
circuit) which are fixable.

Possibly, but will take many years. I'm still waiting for my first fault
like that.

I really can't be bothered to see if there are many more posts or not
about sealed systems versus open vented, I hadn't noticed, you may be
right.

Of course it may be just that there are more pressurised systems. But then
that might be offset by the fact they're also newer.

BTW sealed primary does not imply combi.

Absolutely.

My own house has a sealed primary but pump assisted vented DHW.

--
*What are the pink bits in my tyres? Cyclists & Joggers*

Dave Plowman London SW
To e-mail, change noise into sound.

In article ,
Christian McArdle wrote:
Really? Think if you did a straw poll on here of previous posts you'd
find far more about faulty pressurised systems.

These days, I would think that a significant majority of installations
are of the sealed, pressurised type.

I'd agree, but being newer why so many problems?

Also, we are talking about energy efficiency. Faults in a sealed system
largely result in failure to work at all.

Many typical faults in an open vented system result in the system working
inefficiently, due to such nasties as pumping over, leaving a header tank
full of hot water.

That's not so much a fault as poor design.

--
*Thank you. We're all refreshed and challenged by your unique point of view

Dave Plowman London SW
To e-mail, change noise into sound.

"Christian McArdle" wrote in message
.. .
The question - Assuming all the boilers are of a similar efficiency, is
there an efficiency advantage of a using either a combi boiler, or an
open vented boiler or a system boiler?

An directly comparable instantaneously combi will be more
thermodynamically
efficient in the provision of hot water than a storage system. Whether it
will meet the household needs is another matter.

A sealed system might be more efficient than an open vented one, as open
vented ones frequently go wrong
in a way that reduces energy efficiency.

A one pipe combined feed and vent is virtually trouble free. Install a
Magnaclean on and an air ejector and they work well indeed.