On Wed, 28 Oct 2009, John Rumm wrote:
Kostas Kavoussanakis wrote:
My very friendly installer only does the Vaillant 831 and the
Worcester-Bosch 30Si, and as I would prefer to use his services, I thought
I would investigate. If I read their specs well (I could not find much on
the Vaillant website) they are pretty marginal for my
Try here, for full installation instructions:
http://www.vaillant.co.uk/installers...on/ecoTEC_plus
and here for the controls:
http://www.vaillant.co.uk/installers...cs/controls-2/
Many thanks John!
property (3 bed detached, 2 baths, Scotland; the W-B site recommended the
42CDi or the Highflow 440CDi), but let's not dwell on that.
Marginal for hot water or for heating?
Well, I changed the settings of the search from 2 bathrooms to 1 plus
shower room, and it returned the 30 and 37 CDi and the 30 Si. But the
search is pretty basic:
http://www.worcester-bosch.co.uk/hom.../find-a-boiler
Back to boilers, in terms of features, I (think) I would like weather
compensation, for example. Also, they both appear to modulate, but who can
tell how low they modulate? I also (think I) would like stainless steel
exchangers; have these got them?
The vaillant's have SS HEs, the WB's use silicon coated ali. Modulation range
is something like 3:1 IIRC on both (so a 24Kw unit will go down to 8kW).
The page you linked above suggests the following central heating heat
output range for the ecoTEC plus 831: 8.7 - 24.0kW. Does this mean
that the lowest it will modulate is to 8.7, or is this a different
measurement?
I think you probably need the WB CDi range to support the posher
controls like weather compensation - although that may only apply
for split temperature operation with a cylinder rather than a combi)
I read and saved your post last week re added parts for W-B.
Does modulation happen anyway as a result of demand variation, or does
one need suitable room or external sensors?
Re Vaillant, is the only option for 2 zones the 358-quid Vrc 430 + Vr
61 2 Heating Zone Kit, or can I just add another zone using any stat
and a valve?
So many options, such high costs...
Cheers,
--
Kostas