CM67 Optimum Start algorithm

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My mistake. Are electronic room stats cheaper than bimetallic ones?

Your "real cheap solution" didn't do this. Ergo it wasn't a solution.

Which is relevent to me how, excatly? Am I buliding a new house or renovating?

This is a good start - ask me what I want first, before suggesting a 'solution'. I am glad you have learned something today.

Not at all.

I have gas fired central heating with a non-modulating conventional cast iron boiler which is rated at about double the worst-case heat loss for the house. I have a programmable room stat, with TRVs on 10 radiators and one bypass.
How much would it cost to add individual time/temp control to the system with a view to increasing efficiency without the disruption of moving or reconfiguring pipework?
If you recall, I mentioned that I had been looking at the CM67z and HR80 solution yesterday becasue it appeared to do what I wanted, although at the price indicated I would want more - interfaces to house control system, that kind of thing.
Neil
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In an earlier contribution to this discussion,

Hi Neil,
The CM67z sounds interesting to me as a way of retrofitting some measure of individual room control to an existing system without a lot of plumbing and wiring changes. The main drawback seems to me (apart from the batteries!) to be the fact that each CM67z only controls 2 zones. So if you have (say) 10 rooms, and want each room to do something different by way of temperature profile, you need 5 CM67z's - which could get a bit expensive.
I think that if I were to upgrade my system - which is similar to yours except that I haven't got any TRVs - I would probably fit a 2-port zone valve in the feed to each rad, and have each of these controlled by a programmable room stat. [Ok, I would need 10 stats, but they could be a lot less exotic than a CM67z]. Installing zone valves would not necessitate converting to a manifold system (contrary to IMM's inference) as long as you can get at the feed pipe to each rad in some suitable location. Bringing them all together in a central point would simplify wiring up all the volt-free contacts on the zone valves to control the boiler - but is by no means essential. In my case, at any rate, all the zone valves could be under the upstairs floorboards, and the only exposed wiring would be that going to each room stat - which I would cover with small section white square trunking until the room is next decorated, when I would chase it into the plaster.
--
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Good point, although I'm not sure I have room under the floorboards to house the zone valves, and having them exposed in each room would not have sufficient WAF to obtain budgetary approval :-)
When I first saw the CM67z I considered 2 zones (being nominally 'living rooms' and 'bedrooms'.) Clearly if one room calls for heat the whole system will be switched on, but unless I *actually* zone the system that will happen whatever I do. Battery life looks a definite disadvantage - these valves must be making adjustements on a fairly regular basis. On the other hand it would probably be simple to use a mains transformer instead.
At the end of the day, if it starts getting too expensive I'd be better off replacing the boiler, although that is no simple job either, given the layout of the house.
Neil
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wrote:

A manifold is by far the best method all around, although not necessary.

In your case you could use CM67RFs and no wiring and re-decorating.
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There you go. True to form.....
.andy
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wrote:

Andy, some people have to be told when they are attituding it. Do think he might have been drunk?
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On Wed, 11 Feb 2004 14:25:14 -0000, "Neil Jones"

Wait for the personal insults......
.andy
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wrote:

Or "<rational explanation snipped>"?
PoP
Sending email to my published email address isn't guaranteed to reach me.
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wrote:

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wrote:

As long as you don't have snakes.
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wrote:

Snake free zone round here :-)
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On Wed, 11 Feb 2004 10:56:44 -0000, "Neil Jones"

I've been developing a system which includes this type of functionality plus a great deal more. There are some commercially exploitable aspects, so I don't want to expand on the details as yet.
.andy
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wrote in message > The Hometronic system

Just give us the functionality, not the details. I'm certain it has already been thought of.
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before and I am not even going to describe it in outline.
.andy
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wrote in message > The Hometronicsystem

Give an overview and I will tell you if you are going up a blind alley.
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are.
.andy
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So what does a Suprima having a lockout wobbly have on all this then?...
--
Tony Sayer


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wrote:

You'd need to ask Professor Stanley Unwin that question.
I'm pretty sure that he was IMM's english language teature.....
.andy
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Better get the glass out for the seance then, he threw off his mortal coil a while ago.
Still, could you imagine the glass wizzing about with the answer:-)).....
--
Tony Sayer


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wrote:

Doesn't bear thinking about, does it?
.andy
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