wrote in message
ups.com...
Christian McArdle wrote:
Please do refer to my other post. The time is not unspecified, it is
clearly 10 minutes. It will fill a 380 litre bath in 10 minutes and a
normal bath in a few minutes.
That is not what they explicitly say in the spec.
They give the rate per 10 minutes which is not the same and it cannot
be continuous.
As far as I interpret the figures it is saying (at delta 35):
38lpm for 10 minutes from full store to depleted.
18lpm for 60 minutes from full store to depleted.
15lpm continuous.
With a 37 minute recovery.
In which case, I would conclude (and from the casing dimensions) that it
has
a very sizeable store. Assuming it is essentially a heatbank, I'd guess
(10*(38-15)) * (35 / 70) = 115L (assuming heat store at 75C, incoming
mains
at 5C), plus a few litres for inefficiency, which is essentially a
standard
450x900 cylinder. Indeed, it sounds so like it, it probably is it.
The only spoiler is the quoted 37 minute recovery. The 23lpm (38-15)
delta
35 water should only take 23*10/15 minutes to recover, which is just
under
16 minutes, although it might just be to cover a slow ramping down of
the
recovery rate towards the end, which might suggest an indirect coil
method
of heating.
If it is an unvented cylinder without TMV at 60C, then I make the size
(10*(38-15)) * (35 / 55) = 146L plus a bit.
Christian.
Go to their web site http://www.acv-uk.com. I downloaded the
installation instructions. It is the only domestic combi from a large
commercial range.
IMM said it was a hybrid of unvented cylinder and thermal store. From
the manual: 108.5 litres in the thermal store (it says heating circuit
capacity) and a total of 189 litres which means the unvented cylinder
side is 80 litres. The unvented cylinder is totally immersed within the
thermal store water. The heating is taken from the thermal store water.
The heat exchanger runs right through the centre of the two tanks.
The DHW enters into a coil right at the bottom of the cylinder and then
fills the unvented cylinder at the top after leaving the coil. I think
this is to keep the bottom cool for the condensing part.
The 37 minutes recovery is from cold to 80 centigrade. It will always
give 15 litres per minute minimum. In less than 17 minutes a full bath
could be drawn off (half the 38 litre for 10 minutes, which is 190
litres). If the bath is 125 litres then about 12 minutes or so, 10
minutes or les if replying on the 15 litres per minutes to finish off
at the end of the fill. This thing looks very impressive to me and
performs better than a separate cylinder, and cheaper as well. A 35 KW
Viessmann, or ACV boiler, a tank in tank and the controls to deliver
380 litres in 10 minutes costs more than the Heatmaster and takes up
far more space and time to connect up. I am into delivering flows to at
least 1 bathroom and en-suite, more usually two full bathrooms, and
this baby delivers without any fuss and all in one box which is easy to
connect up. It can be unvented from the mains, or vented if the mains
can't cope, and can't be replaced, and then pumped from a tank. It is
on the list of choices.
I haven't read all this thread but some good stuff here at last. You have
it right. The ACV Heatmaster is a combination of:
1. Unvented cylinder,
2. Thermal store
3. Infinitely continuous combi,
There is no compromise. It uses a stainless steel tank-in-tank and a cool
bottom section to promote efficiency. The best on the market and it does
exactly what it says on the box. ACV are a top quality manufacturer, with
offices all over the world, who invented the tank-in-tank, which has been
available to the commercial market in the UK for many years. ACV have
introduced a domestic range of tank-in-tanks and the ACV Heatmaster in the
UK this year - the domestic Heatmaster 35kW been here a matter of months.
Tank-in tanks are used extensively on the Continent, because of the rapid
re-heat, resistance to corrosion and scale - the best you can get.
The Heatmaster promotes condensing efficiency by having a near sealed,
bottom section that has the DHW coil running through it to pre-heat the DHW,
and keep the bottom section cool. The CH return also enters this bottom
cooler section too. The DHW enters the bottom pre-heat coil and then into
the upper inner stainless steel cylinder (the tank in the tank). This upper
tank is heated from all sides, even the top, being totally immersed in the
thermal store water - It hangs. The stainless gas heat exchanger runs right
though the two cylinders (tanks) and out the bottom.
The figures 380 litres in 10 minutes have been mentioned a lot. To get that
by using a separate tank-in-tank cylinder you would need a large cylinder
and a quality 35kW boiler. The cost is more than the Heatmaster, as you have
gleaned, and no infinitely continuous 15 litres/min combi performance that
the Heatmaster offers. To get the 380 litres in 10 mins using a normal
stainless steel indirect cylinder you would need a large 360 litres
cylinder, which would be bigger than the Heatmaster itself and then the
boiler to try and locate somewhere....and cost more. The Heatmaster, as long
as the thermal store inhibitor is replaced every 4 years, should last 50
years. It is simple, with the burner being a detachable standard part
modulating pre-mix commercial unit.
For a full two bathroom property the Heatmaster is brilliant and great value
for money. It will do three baths as long as three are not run at the same
time (a rare event in a domestic house).
Don't make issue with the lunatics as they have nothing to offer for anyone
to gain from, you have already figured it out. They go boozing with Phil
Kyle. If I had to replace my system right now the Heatmaster would be right
at the top of the list. It is a one off purchase as it will probably
outlive most people.