On Fri, 09 Sep 2005 14:21:53 +0100, Dave Fawthrop
wrote:

On Fri, 09 Sep 2005 13:23:42 +0100, Andy Hall wrote:

| 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?

I took into account my atypical requirements and note the abundance of high
output combi boilers available for those with larger properties and less
insulation. The SEDBUK list gives 7 boilers at over 40kw, which should
cover any domestic requirement.

Even that is an assumption.



| 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.

The EC16 is now no longer produced, so I may mow have to go for the larger
EC23S,

Right - which indicates that there is little market for the low end
that you thought should be adequate anywhere.




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

My bath fills fine with 8 l/m, with 22mm pipe and soft water,from the
present system.

Fine, so if you are happy to wait for 15-20 minutes to fill a bath
then this will seem an improvement.

Personally, I don't have that kind of time to waste on this. I can
fill mine with at least 20lpm each of cold and hot and have the whole
thing ready to go in under 5 minutes.



The higher output combi boilers referred to above have much higher DHW
flow rates. Using the Eco Hometec EC 38 as an example, merely because I
have the data to hand, gives 22 L/min DHW which should be enough for
anybody, without storage.

Because of the spec writing, the rate is actually less than this for
the normal 35 degree rise.

Maybe this is acceptable to you. It certainly wouldn't be for me.
It's quite easy to achieve at least twice that from a storage system
or to drive two showers or a shower and a bath each at at least this
rate.

Why would I compromise on this for the sake of a tiny amount of space
gain?






| 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

To email, substitute .nospam with .gl

Posted Via Usenet.com Premium Usenet Newsgroup Services
----------------------------------------------------------
** SPEED ** RETENTION ** COMPLETION ** ANONYMITY **
----------------------------------------------------------
http://www.usenet.com