On Thu, 21 Jul 2005 01:19:36 +0100, "Doctor Drivel"
wrote:


"Andy Hall" wrote in message
news
On Thu, 21 Jul 2005 00:17:04 +0100, "Doctor Drivel"
wrote:



For quite a while.

However, as the store warms, so
will the return temperature,
and to a point where the boiler is
operating in the range of a
conventional boiler.

Only at the end. The operation temp of the store can be lowered to
promote
cooler operation.

That's useless. Then one can't achieve decent storage for the energy
needed for hot water

You size the cylinder to suit.

Fine. However, you are always the person who promotes stores being
able to be smaller because the water temperature is higher. You can't
have it both ways as has been demonstrated many times.

Next time the Albion rep. comes in, ask him to explain it to you.




If the condensing boiler drives
the radiators directly,

This produces boiler cyling, once the boioer kW has bottomed out.

There are boilers around with 5kW minimum.

Very few, and they still cycle, and still need zone vale and problems with
TRVs.


Rubbish. There are no problems with TRVs at this level.





Not if the minimum modulation level is reasonably low at 5kW or so.

Very rare, and only v expensive boilers and they still cycle.


Your understanding of heat storage and distribution is quite limited,
isn't it....

If you drive radiators directly from a modulating boiler, when the
heat requirement for the space is above the minimum boiler output, the
boiler runs continuously. At the lower end, it also runs highly
efficiently.

When the heat requirement is at or below the minimum output level, the
room thermostat will also play a part and will lock out the boiler
until heat is next required. Any switching of the boiler will be on
a very long interval, just as it is with a store. However, since this
is occuring at a much lower power level than happens when driving a
store, there is less energy waste at the time the boiler fires up. It
will also be working directly in its most efficient temperature range.

Ask one of the boiler reps to explain this to you. Actually don't -
call their technical department.




Problems always when fitting thermostat rad valves.

No there aren't.

There are.

Perhaps you should use decent ones.

Some TRV4s please.




Use of a store makes good sense
for DHW purposes if sufficient mains
flow is available. For space heating,
unless other energy sources are
being added in, it defeats the designed
in optimisation of the boiler
which will then run less efficiently.

Nonsense.

Your department, I think.

You just don't know.

Plumbers merchants seem to be full of people behind the counter who
spout about this or that in an "authoritative" way. Either they
heard it from several heating guys who came in or were told by the
manufacturer's rep as he was telling them about the latest promo trip
to Eyebyeza. When are you going?




--

..andy

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