"simon beer" wrote in message
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"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?
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. 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.
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!
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?
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?
Go Bosch as parts are more readily available and not rip-off. Expertise to
service it is also more readily available.
Go for either a Glow Worm condenser (good value, well made) or the Bosch
Greenstar. If you have long flue lengths then the Kestonis the one to go
for. Don't go regular boiler, go for a condenser. They are well worth the
extra.
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?
Consider a heat bank. Mains water pressure at the taps, so high pressures
showers and no pump, but no high pressure cylinders. Can be DIYed.
For an explanatioin:
http://www.heatweb.com
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. Andy means a quick recovery coil is inside (not just a Part L cylinder).
This will take all the boilers heat output and heat the cylinder in a matter
of minutes. When taking a shower it may be reheating faster than what you
can draw-off water. Fit a second cylinder thermostat, that holds off the CH
side until the cylinder is above 64C. This prevents any boiler cycling, as
when the cylinder is near heated the flow and return temps narrow down to
near each other, then cycling starts. Cycling is inefficient, it also wears
out boiler controls faster. Adding the cooler return water of the heating
system virtually eliminates this. Quick recovery cylinders also use less
fuel to heat them. "Always" fit quick recovery.
Don't go pressurised unvented cylinder. The Megaflow type. You need to be
BBA approved to fit anyhow.
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!
The Worcester-Bosch Greenstar will incorporate a 3-ways inside the case for
you; customer option. Neat and easy, and takes no space. So you just run
pipes to the CH and cylinder and no pumps or valves around cluttering
cupboards.
Any body ever laid slate floor tiles?
See my other post on this.
Use a Honeywell CM67 programmable thermostat. It also optimises and has a
boiler anti-cycle function.
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