"Richard Perkin" wrote in message
...
"Doctor Drivel" wrote in
reenews.net:

... The DHW cylinder sensor (not
sure of price) and the Opentherm standard room temp
controller/programmer/optimiser fitted (Keston use the Honeywell
Chronotherm, which can be bought a lot cheaper elsewhere rather
than the £133 Keston ask for it)...

Err... The programmer badged by
Keston is the Theben Ramses 850 OT.
See:
http://www.theben-ag.com/fileadmin/downloads/BA_RAMSES%20850%20OT%20neutral_2007_01_309%20872_G B.pdf

Here is the Chrontherm on the Keston site:
http://www.keston.co.uk/downloads/userguides/CX51-u.pdf

In the manuals they specifically state Chronotherm.

The reference to OpenTherm has nothing to do with the Honeywell
Chronotherm, but to the OpenTherm protocol used for data communication
between the boiler and the controller. See:
http://www.opentherm.org/

I said, "Opentherm standard", which is a "open" standard used by those who
sign up to it, as the opentherm link you gave explains. Currently is only a
protocol between boiler and room temperature sensor. Two microprocessor
based devices connected via a common "open" protocol so all makers equipment
using the protocol can talk to each other. The boiler and an intelligent
room temp sensor (this may have a sophisticated clock in it as in a clock
stat, like the Chronotherm). There was talk of it 5 years ago, but only
recently have a number of makers started to incorporate it into their pcbs
(Maxie will have to get to know it as he fixes pcb's).

A number of boiler makers use it, mainly German and Dutch, I believe an
Ideal boiler can use the Opentherm protocol. Honeywell, Danfoss, Siemens,
Landis, etc make room temperature sensors which will connect onto these
boilers and modulate the burner or switch the boiler off/on, optimise the
start stop of the boiler, etc (the Honeywell Chronotherm optimises switching
on). Then no rip-off proprietary room sensors to buy, as any makers sensor
will do.

I am sure a Chronotherm using the Opentherm protocol can be bought for under
£133 if you look around. If the Opentherm protocol is implemented further it
will fully simplify boiler wiring and give commercial levels of modulated
burner/pump, etc, control.

Few people in the heating industry have heard of "Opentherm", so many
opentherm compatible boilers will not be used to their maximum efficiency
and I see this boiler being one of them. If pushed properly, even dumb
plumbers could even understand it, it is that simple, with all the control
done on the pcb, not in crude electrical devices external to the boiler, as
is now. The contol is thought out for them, all they have to do is connect
up the devices with wires directly back to the boiler using two core wires
which don't care what way around the wires go in the terminals.