"fred" wrote in message ...
In article , Ed Sirett
writes
On Sun, 23 Dec 2007 19:10:40 +0000, fred wrote:

Andy had me worried there for a minute but it looks like they have
introduced the Qudos 28 as a mid level domestic replacement that fixes
some of the original issues I had with the Celsius 25. There are
separate control temperatures depending on the demand source with
thermistor sensor modulated control of DHW temp and they promise
compatibility with low grade heat from solar panels in the future. Full
list is: Room Compensation, Weather Compensation, Solar Control,
Modulating DHW Reheat, Solar Thermal, Analog Demand (0-10VDC), External
Lockout Signal, Remote Fascia Panel plus LCD control panel and display
of system params (flue temp, flow/return temp, other temp densors) in
installer mode. They've retained the 20m/50mm maximum flue length and
even extended it to 60m when increased to 65mm. Suffix H is heat only
without pump or expansion vessel, suffix S is a system unit with those
parts incorporated.

£722.08 and £788.13 inc vat for the 'H' & 'S' respectively at
discountedheating.

I'm quietly impressed.

This boiler would have the most sophosticated controls of any in that
price bracket.

The sophistication and the solar hook makes it attractive to the
specialist market and the techies here but I do wonder whether it will
make it in the mainstream market, it's just too clever. I hope that they
and it make it, at last a company who listen.

Keston are only doing what the Germans and Dutch have been doing for a
number of years in a limited manner. Vaillant do OpenTherm, yet only on
selected models and not across the range, and up until recently nothing sold
in the UK that I was aware of. The OpenTherm protocol appeared only to be
for Continental models.

Here are the makers who implement OpenTherm. The boilers and the peripheral
devices. It may be slightly out of date:
http://tinyurl.com/2bycs7

The more small third party companies make OpenTherm devices the cheaper they
will become. The hope was that third party pcb makers would make a range of
"standard" OpenTherm pcb's and many boiler makers would use them for their
models. This would also drive down pcb costs too. Then pcb's could be
bought anywhere and fit many boiler models. Just like when you buy parts
for your car and there is a long list of models the part fits. Then a pcb
may be a user replaceable slide in part.