Andy Hall wrote:
On 15 Sep 2005 15:48:37 -0700, wrote:
The ACV Heatmaster 35 KW combi supplies 38 litres per minute of hot
water at 60 degree C. I have all the details.
Clearly you haven't read them properly, or have just looked at the
glossy brochure. Have you been taking dIMM pills.?
That is the short term peak value.
The HM35TC is claimed to be able to deliver 224 litres per 10 minutes
at 60 degrees.
60 degrees? Do you want to have third degree burns? Do you know how hot
that is?
However, the constant flow rate is 9.6 litres per minute at the same
temperature rise of 50 degrees. At the more commonly quoted
temperature rise of 35 degrees, the constant flow rate is 15 litres
per minute which is as predicted by the appliance rating.
I downloaded the installation manual. Here are the figures pasted in
for you, which are very impressive:
----------
DOMESTIC HOT WATER FEATURES
HeatMaster=C2=AE
Operating conditions at 80=C2=B0C 35 TC
Peak flow at 40=C2=B0C [=CE=94T =3D 30=C2=B0C] L/10=E2=80=99 419
Peak flow at 40=C2=B0C [=CE=94T =3D 30=C2=B0C] L/60=E2=80=99 1312
Constant flow at 40=C2=B0C [=CE=94T =3D 30=C2=B0C] L/h 1057
Peak flow at 45=C2=B0C [=CE=94T =3D 35=C2=B0C] L/10=E2=80=99 381
Peak flow at 45=C2=B0C [=CE=94T =3D 35=C2=B0C] L/60=E2=80=99 1080
Constant flow at 45=C2=B0C [=CE=94T =3D 35=C2=B0C] L/h 898
Peak flow at 60=C2=B0C [=CE=94T =3D 50=C2=B0C] L/10=E2=80=99 224
Peak flow at 60=C2=B0C [=CE=94T =3D 50=C2=B0C] L/60=E2=80=99 692
Constant flow at 60=C2=B0C [=CE=94T =3D 50=C2=B0C] L/h 578
Pre-heat time minutes 37
---------
It will deliver 381 litres for 10 minutes at a sensible 45C. That is 38
litres per minute, then drops down to 15 litres per minute continuously
never running out of hot water. Many people on this thread are happy
with less than 15 litres per minutes from their combis. Two
simultaneous baths can be filled. The mains pipe temperature is around
20C at the moment, the ACV would right now deliver 42 litres per minute
for 10 minutes, then down to near 18 litres per minute. That will fill
a large jacuzzi no problem at all. The figures are very impressive and
I have no reason to disbelieve them as ACV are largely in the
commercial market. The new Scottish Parliament building has banks of
Heatmasters. See the ACV web site.
They conveniently omit what the size of hot water storage actually is,
so that one cannot determine the real performance of the system.
The sales brochure describes the unit as "light weight". Hmmm... the
spec. says 170kg empty.
It's also described as "small". The actual size is 670 x 600 x 1700
which is hardly that. It won't even fit into a standard washing
machine footprint. This means that it will either be taking up
valuable space in a kitchen (which would have to configured in a
non-standard way, or to be placed in a cupboard. In effect, the size
is the same as a storage tank and there is virtually no usable space
saving compared with a conventional cylinder and separate small
boiler.
There is space savings. No boiler in the kitchen, which are a pain and
restricts kitchen design, which is great bonus for me. The ACV can go
in then loft like the Powermaxes. A bit of a lift but possible. I asked
ACV about loft mounting they said no problems as the unit is well
insulated.
This is not to say that the design isn't reasonable in principle, but
there is considerable specmanship and hype in the way it's described.
I don't quite understand how it works in detail. ACV have configured a
lower chamber to force cool water for the condensing operation. Perhaps
IMM/Evil can explain. It is all stainless steel which says a lot. I
would not say there is hype in the table I pasted above. It is very
clear. Having over the past 7 years looked at combis that save space
and deliver high flows, the ACV is the most impressive I have seen by
far. It is also one of the most efficient boioers around, whoch is a
good plus point on selling. A rennovated house with a high efficient
quality boiler makes it easier to sell. I=E2=80=99m not sure if it is up to
high continuous flows that the Rinnai delivers for a couple of
simultaneous Tower Showers. The ACV is on the shortlist for the next
job, as is a Rinnai.
=20
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.andy
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