On Sun, 19 Sep 2004 23:40:39 +0100, "IMM" wrote:


You should have TRV on at least all the bedroom rads which is the new
rules AFAIR.

Nothing says it is madatory in the regs.

Building regs part L 2002 guidelines say:

"If a whole heating system is replaced, the controls must permit
independent temperature control in two separate zones: the living and
sleeping areas. This can be achieved with a single room thermostat and
thermostatic radiator valves."

Ideally all rooms should have TRVs except one (the
lounge?) and that room should have the thermostat that turns the
system on/off.

The stat should be in the coolest room which is usualy the hall.

Opinions on this differ. Mine is that I want the room control where I
am, the lounge (being couch potato :-)). I don't care if the hall is
at 17 or 18 or 19. The lounge is where I care about the temperature
so that's what I want to control.

In any case, as you can see from above, the building regs now suggest
the lounge for the stat.

Condensing boilers are far more efficient as they have a larger heat
exchanger, condensing or not.

We are probably talking about oil (me), gas (you). Yes condensing
boilers have a bigger heat exchanger but "far" more efficient? For
oil, a standard boiler on sedbuk rates at about 85% (capped).
Condensing range is 90-95%. Saving is thus 5-10%.

In my case I want a wall mount oil fired and from sedbuk there is only
one oil fired wall mounted (and it's not available anymore). That one
is only 90% and a lot more than GBP200 more expensive! Sedbuk reckons
running costs are 400 pa for my sort of house which I'd agree with.
So 5% saving is 20 pa. Pay back is 10yrs

I wouldn't go with an alpha pump with a standard boiler.

I would use a condesning boiler.

For a condensing boiler an alpha would be good, which is what I said.
With an alpha the return temperature goes down. Bad news for a
standard boiler but just what you want for a condensing.

What I would go for is a standard pump +
an automatic bypass (which is cheaper
anyway).

And difficult to get right.

What is difficult? As the TRVs cut in the flow resistance increases
and the pump head rises. You just need to have the bypass set higher
than the fully open condition. After that everything is automatic.

You need to know more about regular v condensing boilers and much, much
more.

From someone who doesn't seem to know about part L or the performance
figures it seems very patronising.


--

Malcolm

Malcolm Reeves BSc CEng MIEE MIRSE, Full Circuit Ltd, Chippenham, UK
, or ).
Design Service for Analogue/Digital H/W & S/W Railway Signalling and Power
electronics. More details plus freeware, Win95/98 DUN and Pspice tips, see:

http://www.fullcircuit.com or http://www.fullcircuit.co.uk

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