Town house and a new boiler



Of course I realised it - that's one of the reasons why I spoke to Keston. I (like you) also realised that the asking price for the 'Keston' controller was high - but the company couldn't/wouldn't suggest an alternative, and I struggled to find one. Perhaps you know of others readily available in the UK? Or (for the rcord) where the Honeywell OT device can be purchased?

The same name and part numer are in the C36 manual. The same product info was also on the Keston site 18 months ago. When I ordered the controller, what was delivered was the Theben device *not* a Honeywell.
Perhaps things have changed - you could try ringing them up...

It's best described as 'adequate'. I was hoping for better - indeed, a major reason for selecting the C36 was its high output (CH output OTT for my house, although of course it's fully modulating so no problem there) and consequent high DHW flow rate. The spec is: 14.5 l/min @ 35deg C rise, 17 l/min @ 30 deg C rise.
However, despite this it is still slower than I would like to fill a bath with 'properly hot' water. However, the flow rate for a drencher shower is truly excellent, as you would expect.
The bolier is sited some distance from the bathroom, and the length of pipework has a significant impact as there is a considerable 'slug' of cold water to come from the tap before the hot water flows well.
But these are well known consequences of using a combi, so I'm not surprised.

No, it doesn't quite work like that. The Theben controller has two modes of operation: you can set a target room temperature, or (if the external temp sensor is present) use weather compensated control.
Weather compensated control is the default when the sensor is fitted, or more accurately, since the snsor is connected to the boiler system, when the boiler tells the controller via OT that it is present. When it is used, the controller uses a predefined heating curve, but it is possible to set the start and end points. This is very poorly explained in the manual (read it at the link above) and I am using the default settings.
This seems to work OK. All rads but the usual suspects (hall, bathroom) are fitted with TRVs and the controller is in the hall. If it were set for a fixed target temp I would use 21 deg C - in practice it works automagically with a displayed temp of around 21 - 22 deg. Room temp is controlled by the TRVs, but the controller + weather compensation ensure that the CH flow rarely rises above 65 deg (although the max would be 82 deg).
As I write this the controller says the (hall) room temp is 22.6 deg and the flow temp is 43 deg against an outside temp of 8 deg.
The house is always comfortably warm. In fact many visitors find it hot, but having spent a very cold Derbyshire childhood I vowed never to be cold again, so we like it like that :)
Quite how the device implements the control I'm unclear (which is unlike me - I like to know the nitty gritty) and I'd prefer to 'play', but the default setting works well and the running costs are low.
Kind regards
--
Richard Perkin
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Try Honeywel first. :-)

14.5 litres/min is not starting.

Dead leg pipe is well ...dead-leg pipe and will be the same whether from a combi or a cylinder.

That is probably the function of the pcb. It appears it can't do weather compensation "and" room temperature influence on the compensation.

It "appears" it is either or. Weather compensation or room temperature control depending what sensor is connected.
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It isn't too clever once people understand that all you do is hook up simple sensors back to the boiler. The thinking is done for you. DHW sensor has it own terminals as does the room influence and outside weather sensors too......and also the zone valves as well. Super simple to wire up.

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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.
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Is that a good thing? ;-)
--
*Starfishes have no brains *

Dave Plowman snipped-for-privacy@davenoise.co.uk London SW
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The C55 (55 kW) is 1821. Two Qudos 28 kW boilers is 1576. ...and a back up boiler in case. With the right boioper sequence controller this will modulate from about 6kW to 56 kW.
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F wrote:

That sounds like bollocks to me.

May be an issue with condensing types. Dunno.
My guess is that otherwise water drips down the flue pipe or summat.
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On Sun, 23 Dec 2007 13:55:42 +0000, The Natural Philosopher wrote:

Agreed, except for cost issues about the length of flue components etc.

Varies from maker to make but invariably they are all competing with each other to make things as long and as versatile as possible.

One of the make requires a drain+trap at the base of vertical sections of above a certain height.
--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
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A boiler can go in the loft, flued through the roof.
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On 23/12/2007 19:21 Doctor Drivel wrote:

She doesn't have a loft, just a top floor.
However, my neighbour has had a boiler installed in her loft. It went AWOL after a few months, BG came out to fix it (the original fitter couldn't get out to it and there were young children in a very cold house) and the guy refused to go up into the loft. Elf and safety! He was persuaded to change his mind when said neighbour asked him what his supervisor would say when he smelled the alcohol on his breath!
--
F

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Must be boarded from hatch to boiler. A permanent light, and a shoot down ladder. Then he can't refuse.
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Look at: http://www.keston.co.uk/downloads/manuals/installation-servicing-instructions-Q28S.pdf
Long flue lengths using plastic drain pipe.
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Brilliant thread, it will help me choose a new boiler/ controller in the spring.
I had a Camray 70/90 Oil boiler in my previous house controlled by a Honeywell AQ6000, a brilliant controller unfortunately no longer made. I installed and commissioned it in August 1996, never had any problems with the boiler or controller and AFAIAA the new owners (4Yrs) have had good service from it. However, new technology, we must move on, am looking forward to getting to grips with it.
Regards Don
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