Hello All,

I have been following the recent excellent threads and am now coming
out of my confusion, I think.
Our existing solid fuel boiler is not going to cope with the
additional requirement of our extension and will be replaced by oil in
the nearish future. This will allow some degree of control (yippee).
My original plan was simple DHW stat and TRV's on all rads, but this ,
I now see, has difficulties in achieving 'boiler interlock'

From pointers given by various recent posters I believe I want:
1) two CH zones, since I have identified that all our rooms fall into
one of two distinct heating requirement patterns.
2) separate control of hot water.

Now... someone (BillR, I think) mentioned the Honeywell CM67's. Having
investigated, these look excellent, allowing each heating zone to be
controlled to different temperature levels throughout six different
periods of the day. I particularly like the look of the RF versions
and, AIUI, by linking to an additional HC60NG to be used as the
boiler/pump controller - as per honeywell installation guide - I
could then have TRV's on all the radiators except those in the 2 rooms
(1 room in each zone) where the CM67's are installed and this would
provide the required 'boiler interlock'. I think I'm OK with this so
far (?) Someone tell me if I'm not!

Then I come to the DHW....
I cannot see an equivalent beast to the CM67 for DHW purposes....
I guess I can use a simple cylinder thermostat - although I don't
necessarily want to have a tank full of hot water permanently. Even if
I did, how do I get this stat to talk to the HC60NG that is
controlling the boiler?? I am sure I am missing something very simple
here but cannot put my finger on it.
It may become clearer when I have the boiler installation information
to hand but in the meantime, I'd really appreciate if some kind soul
can enlighten me.

Perhaps there is something to be said for the old anthracite boiler...
a) light it once a year - DHW control is sorted
b) switch on the pump when you want the CH
c) twiddle with the TRV's
d) switch the pump off at bedtime
e) heat leak rad keeps the bathroom warm for the overnight tinkles and
f) the heatloss from the boiler keeps it warm for breakfast!
arhhh the simplicity!

TIA
Ian