On Fri, 09 Sep 2005 08:42:59 +0100, Dave Fawthrop
wrote:



As I am putting a combi system in specifically to get rid of the hot water
cylinder, and have worked out that the smallest combi will provide more
liters per min of hot water than the present system, and more importantly
will provide one bath after another, which the present system struggled
with. I will stay with the combi.

Most DIY domestic combi installations will have the same requirements as
myself.


This is complete nonsense.

Most domestic installations clearly require more CH boiler output than
you which is why most boilers available are in the 20-30kW range.
Didn't it occur to you that the reason that there were so few
available at the bottom end of the range was because your requirement
is not typical?

You mentioned the MAN (Eco- Hometec) EC16 boiler. Although this make
is an excellent boiler, the hot water output rate from the combi
section is disappointing because the input power level is so low at
22kW for HW. This provides a flow rate of 10.5 litres/min at a
temperature rise of 30 degrees. The industry standard is to use 35
degree measurement and so the flow rate is actually 9 litres/min.


This means that during the winter, it will take 15 minutes at least to
fill a bath.

If you are happy with that level of performance, then fine but it is
more than a stretch to say that most installations will have these
requirements.


--

..andy

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