hi all,

been trawling through the search engines for two days and decided I
know less about the options I have than when I started.

The Problem:
I currently have an open vented heated system, that is under speced
from the boiler point of view and I am trying to suss out what is the
best road map to change the system to what I want without ripping it
all out in one go as I can not afford it.

Main issues to be sorted a
When the heating system runs the overflow overflows constantly
Hot water is at too low pressure
I would like to add a radiator in the loft at some point as it is a
walk in room

Solutions ?

I am thinking that using a thermal store will give me the mains
pressure hot water I want while still using the open vented system
Installing an airseperator from what I read on the net should stop the
overflow issue, but not found one that I can buy
convert the system at a later date to either a closed system or buy a
boiler that is already a closed system to get the hot water in the
loft. Can you get such boilers that are not combi boilers or do I
need to install the parts. If that's the case, do I need to put the
expansion vessel near the boiler and hence in the kitchen..

How would others tackle the problem ? useful urls for suppliers like
the air vent would be welcome, the ones I have found seem to be
targeted at just removing the air

many thanks and cheers

ian

ian tracey

The easy answer is something like the Baxi system boiler, this contains
pump, air vent, safety valve, expansion vessel, and of course the boiler.
just add two zone or one three port valve to connect to your system, and
remove the existing cold feed and vent. IMHO a Megaflow is better than a
thermal store not least because of the large volume of water to treat with
inhibitor in a thermal store, also thermal store are less efficient due to
there higher operating temp.

--
Muddy Paws
(remove muddy paws to reply)
"Ian Tracey" wrote in message
...
hi all,

been trawling through the search engines for two days and decided I
know less about the options I have than when I started.

The Problem:
I currently have an open vented heated system, that is under speced
from the boiler point of view and I am trying to suss out what is the
best road map to change the system to what I want without ripping it
all out in one go as I can not afford it.

Main issues to be sorted a
When the heating system runs the overflow overflows constantly
Hot water is at too low pressure
I would like to add a radiator in the loft at some point as it is a
walk in room

Solutions ?

I am thinking that using a thermal store will give me the mains
pressure hot water I want while still using the open vented system
Installing an airseperator from what I read on the net should stop the
overflow issue, but not found one that I can buy
convert the system at a later date to either a closed system or buy a
boiler that is already a closed system to get the hot water in the
loft. Can you get such boilers that are not combi boilers or do I
need to install the parts. If that's the case, do I need to put the
expansion vessel near the boiler and hence in the kitchen..

How would others tackle the problem ? useful urls for suppliers like
the air vent would be welcome, the ones I have found seem to be
targeted at just removing the air

many thanks and cheers

ian

ian tracey

Thanks MuddyPaw, can you be kind enough to explain the line:

thermal store are less efficient due to there higher operating temp.

is it because the higher temp = greater loss across the tank insulation ?

cheers

ian

"Muddy Paws" wrote in message
...

The easy answer is something like the Baxi system boiler, this contains
pump, air vent, safety valve, expansion vessel, and of course the boiler.
just add two zone or one three port valve to connect to your system, and
remove the existing cold feed and vent. IMHO a Megaflow is better than a
thermal store not least because of the large volume of water to treat with
inhibitor in a thermal store, also thermal store are less efficient due to
there higher operating temp.

Not so. A heat bank, with a plate heat exchanger is more efficient than a
Megaflow. They also can operate at very high cold mains pressure, where a
Megalfow operates, typically between 1 and 3.5 bar. If you have 6 bar mains
, a heat bank will allow 6 bar for hot water. A heat bank has no complex
pressure reducing and blow off gear, high temp cut outs, large overflow
pipes, tundish, having to service it each year, high pressure water storage
(when they go it is a full insurance job for the house), etc

You can have only a small amount of hot water at the top of a heat bank and
they will deliver useful hot water, which is not the case with an immersed
coil thermal store. Heat banks and thermal stores are not quite the same
thing. A heat bank can be DIYed, A Megaflow requires a BBA approved fitter.
Expensive!!!

Many councils have been bitten by unvented cylinders (Megaflows). Constant
callout for dripping overflows, etc, that they are going to heat banks.
Some heat banks don't even have overflows.



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"Ian Tracey" wrote in message
...
hi all,

been trawling through the search engines for two days and decided I
know less about the options I have than when I started.

The Problem:
I currently have an open vented heated system, that is under speced
from the boiler point of view and I am trying to suss out what is the
best road map to change the system to what I want without ripping it
all out in one go as I can not afford it.

Main issues to be sorted a
When the heating system runs the overflow overflows constantly
Hot water is at too low pressure
I would like to add a radiator in the loft at some point as it is a
walk in room

Solutions ?

I am thinking that using a thermal store will give me the mains
pressure hot water I want while still using the open vented system
Installing an airseperator from what I read on the net should stop the
overflow issue, but not found one that I can buy
convert the system at a later date to either a closed system or buy a
boiler that is already a closed system to get the hot water in the
loft. Can you get such boilers that are not combi boilers or do I
need to install the parts. If that's the case, do I need to put the
expansion vessel near the boiler and hence in the kitchen..

How would others tackle the problem ? useful urls for suppliers like
the air vent would be welcome, the ones I have found seem to be
targeted at just removing the air

I determine You need:

1. a new boiler.
2. a rad in the attic above the cold water tanks
3. better hot water pressure for high pressure showers.

Solution:

1. a new "system boiler" that has the pump and expansion vessel
incorporated.
2. a DHW only heat bank that has a boiler coil incorporated, to give:
a) high pressure hot and cold supplies,
b) a pressurised CH system that will allow your radiator in the loft

The above will allow rads and hot water anywhere in the house. You can
start by installing a heat bank only, and then the boiler and rad when money
is available.

http://www.heatweb.com
http://www.albion-online.co.uk
http://www.range-cylinders.co.uk (look at thermal storage [heat banks])
http://www.discountedheating.co.uk



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"IMM" wrote in message
...
lots of useful stuff, so I just want to say thanks for your help

cheers

ian