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Doctor Drivel
 
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Default Choice of system boiler: Worcester Bosch or Glow-worm?


"Andy Hall" aka Matt wrote in message
...
On Sun, 5 Mar 2006 20:58:00 -0000, "Aldrich"
wrote:

Hi

We need a new system boiler for our house. Our local installer is likely
to
recommend a Glow-worm 30sxi but I have heard good things of the Worcester
Bosch Greenstar 28HE system. Would anyone like to comment on these two
choices? Is one clearly better than the other?


Glow Worm used to have a really bad reputation in terms of their build
quality. I threw out an old one that at the time was 18 years old
(Fuelsaver) about three years ago and vowed never to have another.

I looked at others, including Worcester Bosch, Vaillant, Keston that
have been regarded as good quality condensing system boilers.

For reasons of the build quality, design, specifications and controls,
I eventually settled on a MAN Micromat.
http://www.mhg.de/en/products/gas_un...cromat_ec.html

This one has wide modulation range, weather compensation, analogue
sensing of room and water temperatures etc. It has been a good
choice, and I'd go for one again. However, the price tag is about
twice that of the ones that you are considering.

One of the reasons that I was put off by the Bosch originally was the
aluminium-silicon heat exchanger. I couldn't find many reliable
references to the suitability of this material for condensing boilers,
whereas stainless steel, of the correct grade is a well understood
technology. Having said that, people in this NG do have Greenstars
and are happy with them as I understand it.

I've just been looking through the installation manual of the Glow
Worm and it's very clear that the influence of their ultimate parent,
Vaillant, is in the design. For example, the heat exchanger and
burner are of a similar design to that of the Micromat - basically a
radial burner with stainless steel tube heat exchanger.

The same concept is used in a larger installation/commercial version
of the Micromat - the Strata 1.

This data sheet has some pictures of the internals such as the heat
exchanger and burner and hook ups with multiple units for commercial
use.

http://mhsboilers.com/pdf/boiler/str...-0206-5624.pdf


I like the 38, which is two boilers in one case. The inards are shown.
Although using two separate Glow Worms or Vaillants would do the same thing,
and "maybe" cheaper. Eco-Hometec rebage these boilers.