Which Worcester-Bosch Combi?

[Lobster]

At the risk of kicking off yet another combi thread...

I'm very confused by the plethora of different W-B condensing boilers on offer, and what the difference is between them. Trogging through the blurb on the mfr's website is like a game of 'spot the difference' - I don't know why they can't publish a straightforward comparison table.

There seems to be: Greenstar CDi (25CDi, 30CDi, 35CDi, 40CDi) Greenstar Si (25Si, 30Si) Greenstar Junior (24i junior, 28i junior) HE Combi (25 HE, 30 HE) HE Plus Combi (30 HE Plus, 35 HE Plus, 40 HE Plus)

CDi and Si seem to be comparably priced; with the Junior and HE a fair bit cheaper. As I reckon I want about 28kW, I'm apparently in the market for any of the above AFAICS? Anyone done the research and care to enlighten me?!

Thanks David

[jacob]

I has 24i and it was seriously unreliable and expensive to fix - just out of guarantee. Crap basically.

[Matt]

as if.....

I thought they had a selection program on their website to guide you to the correct boiler?

I think it plays the theme from "The Omen" when you choose a combi ;-)

[Ed Sirett]

With the regulatory changes (so that only condensing can be officially fitted) the manufacturers, pricing and models seem to be in turmoil.

The Si range are system boilers. I think that the Juniors are replacements for the earlier CD range with smaller cases (i.e. more cramped components).

[Andy Hall]

It's a good time.

When there's another six running, one more makes little difference.

Did you think about two 14kW ones?

[Lobster]

Erm - don't think so (see

or )

Actually I've just found a pdf brochure on the W-B site which (on p27) gives a comparison matrix of all their boilers; just what i was looking for before! But hey, I'm still none the wiser; they all seem to almost indistinguishable other than the obvious differences in output - see

(or

Dimensions of the Juniors are 710x330x330 mm; identical to the Si range and a bit smaller than the rest. Does that mean their performance is compromised by being crammed with their condensers into a suboptimal space? And why are they cheaper than the Si's??

Still very confused...!

David

[Lobster]

Mm, they do; that's where I'm coming from actually. From my specs, it picked out 4 apparently equally suitable condensing combis, and apart from the obvious output differences (approx proportional to the respective boiler ratings) I can't see any obvious differences in them!

David

[Christian McArdle]

New condensing combi range. Replaces the HE Plus.

New condensing combi range. Replaces the HE.

Compact version in smaller case.

The old range, being discontinued.

The old range, with various extras and option of increased power. Being discountinued.

Don't forget the CDi Xtra (no Greenstar). Avoid that like the plague. It isn't a Greenstar CDi on the cheap.

Christian.

[Lobster]

OK, so what's the difference between the 25 and 30 kW versions of these two (ie why the overlap between the ranges)?

Yeah that's what Ed said too. However, as I mentioned in my reply to him, the dimensions stated on the W-B site are identical to the Si!

OK, so we'll drop them off the shortlist then.

Already forgotten! I'd read your previous posts on that!

Cheers David

[Christian McArdle]

I don't know exactly. On the old HE, there were differences in programmers, weather compensation and such like. I would suspect similar differences. It would probably require a trawl through the detailed technical specs.

Christian.

[Ed Sirett]

)

This is seriously confusing. I worked on a 28Si earlier this year and that was not a combi. But a 30 Si is....

Um...

[John Rumm]

Using "Junior" to imply a small case always seems like a bit of a marketing goof to me. Junior normally implies less well featured or "cut down" in my mind. "Greenstar Compact" would sound a little more classy don't you think?

[Lobster]

OK, enough is enough - time for a chat with W-B technical! I asked them specifically about these ranges:

Junior:

- Aimed at contract market

- Has no temp control for HW, this is factory-set (unlike other models)

- (Same size case as Si)

Si:

- Very similar to Junior but with user-adjustable HW temp.

- Same heat exchanger

- Better HW flow rate (although I think this is proportional to the nominal power outputs, which don't match between Si and Junior)

CDi:

- Top-end model

- Has different heat exchanger to others, with bigger surface area

- Condenses in HW mode as well as CH mode, which gives it an overall actual efficiency rating of about 97%, compared with normal SEDBUK ratings of about 90% for this and all the other W-Bs (SEDBUK doesn't assess HW condensing)

So there we have it! David