On Mon, 17 Nov 2003 09:17:12 -0000, "simon beer"
wrote:


"Andy Hall" wrote in message
.. .
On Sun, 16 Nov 2003 22:54:49 -0000, "simon beer"
wrote:


System pipe work is also all in 15mm which could do with beefing up to 22
on
the main circuits if my thinking is right, any thoughts?

This really depends on the amount of heat that the pipes are
transporting. Before doing major surgery, it would be sensible to
calculate the requirements.

Did a quick calc using B&Q's radiator sizing quide. I know this not to
accurate but gave me a starting point. I downloaded Barlow Heatloss but it
seems to be very buggie (on my machine) and keeps crashing. Myson Heatloss
Manager is presently not available for download, got a copy you could email?

On its way to you.


My lad is an apprentice plumber, he will be doing a lot of the change over,
his tutor said to him that the pipe bore should be in 28mm but I think this
is overkill.

It may or may not be. Until you do the sums you can't really be
sure. Typically 22mm is enough but it does depend on pipe lengths
and how branches are arranged.


My lad would be competent to do the work but has no experience
on conventional heating boilers or the sealed systems as his firm has a lot
of contracts for fitting combie boilers. I don't think they vary there
experience enough in the domestic situation.

Generally combi boilers have sealed CH systems connected to them
anyway often with the components like the pressure vessel built in.



If it were me, I would work from first principles and not trust
anything already there. It seems that a lot of professional
installers work from fag packet rules of thumb and guess what is
required based on the area of the rooms multiplied by granny's
telephone number.

I suspect the B&Q method!

It is pretty inaccurate.


If the system is otherwise heating the rooms adequately (you won't
know for sure because it hasn't been cold enough yet), then you can
start part way through and assume that the radiators are adequately
sized.

As you say not cold enough yet, but most rads are up on the max on there
T/valves. This is far better however than anything we have had before. Never
had C/H our last house had storage heating. The sound of a boiler fireing up
is a very comforting sound.

In this case, find something looking the same on a
manufacturer's data sheet and determine radiators the same or close
in size to what you have

Will give this a try

The only note that I would add is to make sure that you clean
the system very thoroughly (I've posted a way to do this a few times)
and be prepared to change the radiator valves as they may seep under
pressure. You are not talking about a lot of pressure - typically
2bar max. but it can be enough.

We just drained down the system at weekend and added a cleaner into the
refill, is this adequet?

Take a look at a radiator afterwards and see whether there is any
substantial amount of sludge. If so, have a look for my method of
cleaning.




I would definitely consider going for condensing models from either of
these manufacturers. The Thermocompact and the Worcester Bosch SBI
only just scrape in above the minimum Building Regulation requirement
of 78% SEDBUK efficiency.

Apart from the condensing side of it though you would say that there is not
much to chose between the 2 brands and models?

Several people here have installed and been pleased with Keston
Celsius 25 which is a good value for money product,

I will take a look at it.

If you do decide to stick with a vented HW system, and it certainly
does have a number of advantages,

What are they, in brief?

- Availability of a lot of simultaneous flow if you have multiple
baths, showers and other appliances, independent of what the mains
water supply is doing.

- Storage of water in the event of mains failure.



then it is worth changing the
cylinder for a fast recovery type to improve HW reheat performance
while you are at it.

Do you mean a S/S preasurised hot tank or is there something else?


No, it means an improved (= larger surface area) heat exchanger/coil
in the cylinder.


I suspect that both of these will end up being chucked out and
a system of motorised valves used instead. The pump in a system
boiler should be able to do everything.

Yes just got to work out the motorized valve bit!

Any body ever laid slate floor tiles?

Yes, and it is very hard work if you use the larger ones.

30 X 30 cm do you call them the large ones ?

No, these aren't too bad. I have some 600x400 tiles and these are
substantially heavy if laying a lot of them.





Thanks for you help Andy.


..andy

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