"Mark Trueman" wrote in message
...

"IMM" wrote in message
...

"Mark Trueman" wrote in message
oups.com...
Hi all,

Yes, it may be the first failed diverter valve of the year, and it has
inspired me to thing about replacing my whole system. Firstly a bit of
background about the current system.

House is a 2 bed end terrace, currently only has 5 radiators, one in
the lounge (open plan to dining room), one in the kitchen extension
(which gets really cold in the winter - insulation problem there i
think), one in the master bed, one in the hall and one in the bathroom.
Second bedroom doesnt have a rad. They are all old rads, no TRVs or
anything. The system as a whole is absolute crud. Some of the rads are
in series with each other, some (in the kitchen extension) are teed
off. Hot water is heated indirectly in a standard cylinder in the
second bedroom airing cupboard. Theres a pump and a diverter under the
floor(!!!) in the dining room, by the Baxi back boiler. As SWMBO wanted
laminate, thats the replacement of that scuppered. I dont even think
its all plumbed in right, you have to have the hot water on for half an
hour before you have the heating on in order to get any hot water at
all. I think that the hot water is pumped through the rads before it
heats the cylinder water, so its cold by the time it gets there!!

Our only requirements of the new system are....

6 new radiators and pipework that must be hidden underfloor
(floorboards and joists), sized to handle our heat requirements.

Keeping the ability to store hot water in the cylinder - two reasons
here which i think are valid - 1. our venturi shower wont work without
a hot water cylinder. 2. The wife likes the occasional bath.

I am umming and aahing about whether to do this diy, as it needs to be
in before it starts getting really cold, and working full time, i dont
have much of it spare to do something like this. And of course, i
havent done a central heating install before. Im confident that my
plumbing and electrical skills are up to it though.

Also, i need to keep the cost around the 1500 mark.

So on to my questions and musings.....

Can i easily keep the current indirect heating system used for our hot
water, while replacing the central heating section. Can a
combi/condensing boiler do indirect water heating efficiently.

Pipework under laminate floor - any suggestions. I think removal of
aforementioned minging flooring is the best option.

TRVs/Thermostats etc... We just want the whole house to be warm, not
really bothered about upstairs being cooler than downstairs etc. Whats
the best way to do this. Im guessing at trvs on all rads (except
bathroom one), but would you recommend a room thermostat in the lounge
to tie in with these. If someone could explain the need for room
thermostats when you have trvs i would appreciate it (seen a few
installs with trvs and thermostats but dont really understand why you
need thermostats when the temp is controlled by the trvs)

Types of boiler/boiler recommendations that fit in with our budget
would also be appreciated.

Im sure there are a load of things ive missed out, but any pointers
would be appreciated (and yes, i have read the faq etc)

Mark,

To DIY go combi. they are a doddle to fit and are quicker too. It will
modulate down to the heating needs of the small house. No complex zone
vales
or control wiring, etc. You will need a decent flowrate as you will
want
the occasional bath. A condenser? try the Worcester-Bosch Greenstar
40kW
combi at 16 litres/min. You will not be disappointed.

You will be using most of the existing rads, so no great thing there.
Put
de-sludge in the system for as long as you can (max one month), before
you
rip out the old boiler. Flush well. Look at installing a kickspace
heater
in the kitchen. Put TVRs upstairs only.


http://www.discountedheating.co.uk/s...40HE_PLUS.html




At 1300 for that boiler alone, i think my budget of 1500 can not be met by
your suggestion.

Radiators will need replacing as they must be about as old as i am, no
bleed
valves on them or anything. Load of rubbish they are

And as much as i would love a TVR , it would probably break down on the
way
up the stairs

But thanks for the info anyway

The Alpha CB50, a non-condensing boiler is around £1100 and will deliver
around 19 litres/min to fills a bath pronto. Great for showers and baths.
£300 should be enough for rads in a two bedroomed house.

Or look at the two combi suggestion in one of my current posts. Two W-B
Juniors for around £100-1100, to give bath flows. As a DIYer you should be
looking at combi's, as they offer so much for a DIYer.

Here is a run down on combi's:

Firstly, a combi is a "combination" of the heating and water system in one
case, eliminating external tanks and cylinders, and generally supply hot
water at high main pressure. To confuse a little, some can run at very low
pressures and even off tanks. Generally most are fed from the mains. It is
generally a matter of mounting the boiler and connect up the pipes. The
expert designers have done the hard work for you and put all in one case.

Types of combi:

1) The Infinitely Continuous Combi -

Heats cold mains water instantly as it runs through the combi. It never runs
out of hot water. This is the most common type of combi, generally having
lower flowrates than Nos 2 & 3 below. The largest flow rate instant combi is
a two bathroom model, 22 litres/min ECO-Hometec. Being a condenser it is
very economical too. http://www.eco-hometec.co.uk

2) Unvented Cylinder Combi -

An unvented cylinder is a similar to a conventional cylinder but run off the
high-pressure cold mains. A combi with an integral unvented cylinder has
approx 60 litre cylinder heated to approx 80C, with a quick recovery coil
that takes all the boilers output. A fast acting cylinder thermostat ensures
the boiler pumps heat into the cylinder ASAP with a recovery rate from cold
around 5-8 mins (Ariston claim 8 mins). The 80C water is blended down to
about 45-50C. e.g's, Ariston Genus 27 Plus, Glow Worm, Powermax, Alpha
CB50.

3) Infinately Continuous/Unvented cylinder combi -

An example being the Alpha CB50, a combination of both having a two stage
flowrate, of high flowrate when using the stored water with an automatic
flow regulator switching in to reduce flow to an invinately continuous
flowrate of approx 11 litres/min.
http://www.alpha-boilers.com/products/CB50.html

4) Heat Bank Combi -

Incoming water is instantly heated running through a plate heat exchanger
(as is most instantaneous combi's) that takes its heat from a "domestic hot
water only" store of water at approx 80C (instantaneous combi's take the
heat from a heat-exchanger heater via the burner). A fast acting thermostat
ensures the boiler pumps all of its heat into the store ASAP with a recovery
rate about 5-8 mins from cold. The 80C water is blended down to about
45-50C. They are generally two stage flow rates, in that when the thermal
store is exhausted it reverts to what the burner can produce, which is
approx 11-12 litre/minute. e.g. Vokera & Worcester floor standing models
(standard washing machine sizes).

N.B. The heat bank is a variation of a thermal store, but is "not" a thermal
store in the conventional sense in that a coil carrying cold mains water
runs though a store of hot water kept at about 80C. Heat-banks are far more
efficient and give higher flowrates than conventional coiled thermal stores.
The stainless steel plate heat-exchangers do not scale up so easily.

5) Combined Primary Storage Unit

(Not classed as a combi, but a derivative of a combi, but still a one box
solution, so still in the same family)

These are a combination of a large thermal store, or heat bank, and boiler
in one casing. The units are large (larger than standard washing machine
size) and floor mounted. The heating is taken off the thermal store, which
in many cases the DHW taken off the store using a plate heat-exchanger
(heat-bank). Unlike the Heat-bank in 3) above the thermal store supplies
heating "and" DHW, giving the "combined" to the title. They are available
from 1 to 2.5 bathroom models. Gledhill do an excellent condensing
version, the Gulfsream 2000. http://www.gledhill.net

Nos. 2), 3), 4) & 5) have high flowrates. No. 1 "generally" has low
flowrates but there are always exceptions and some can be high - e.g. the
ECO-Hometec infinitely continuous combi, actually has a very high flowrate.
Nos 2), 3), 4) & 5) use stored water, but in different ways. Unlike No. 1
"some" versions will eventually run cold, but that takes quite a time, hence
some are referred to as "two bathroom" models, having the ability to fill
two baths with very fast recovery rates. As hot water is being drawn off
the high rating burner is also reheating. Very rare do these combi's run
out of hot water in average use. When taking one shower the burner may be
re-heating faster than what can be drawn-off. No. 3) above uses stored
water but will not run out of hot water (high and low flowrates). Most
versions of No. 4) above are two stage flowrate models (high and low
flowrates) and will also not run out of hot water.

There are combi models that give hot water and heating simultaneously as
Combined Primary Storage Units do. Most don't as they are hot water
priority.