Worcester Bosch Greenstar 24ri

[Mike]

Forgive the question if it has been answered many times before, but I am new to this NG.

I am planning to replace my ageing Potterton boiler and have received a quote from the plumber (Stevenson) who installed it. They have suggested a Worcester Bosch Greenstar 24ri.

Any thoughts or views on this choice of boiler would be welcome.

TIA

Mike

[John Stumbles]

Personally I think that's a fine choice, but then I've fitted practically nothing but Worcester Greenstars since condensing boilers became mandatory[1]. I tend to fit the 24i Junior combis, even when a system boiler might otherwise be indicated (the combis are actually cheaper than the system models, even though the latter are the combi with some bits

*left out*!

The ri you've been recommended is the heating-only model and it sounds as if your installer is planning to keep your system vented, with a header tank in the attic. Ho hum, I usually convert to sealed - I suggest you check out Ed's Sealed CH FAQ

for discussion of the pros and cons.

My only query would be the choice of a *24* ri. 24kW is a *lot* of power for heating only (though the bottom of the range for a combi, where much more heat is needed to provide hot water instantaneously). I'd be asking why? Do you have a poorly insulated mansion? Has your heating engineer done the boiler-sizing calculations? (See

go to Heat Requirements section of . Your engineer is probably going to have to upgrade the gas pipe to the boiler to accomodate the extra power, and if your house really needs that much power I'd consider putting in the combi (which would mean converting to a sealed system) to give you a mains pressure instantaneous hot water output for showers, even if you keep your hot water cylinder. And then I'd ask what benefit you get from keeping the cylinder - but that's another question - see [1] to a first approximation

[Mike]

Thanks John

Stevenson installed the original system. I doubt if they have done any recalculation. But I will query the size of the boiler.

Cheers

Richard (on behalf of his aged father who is a little new to the idea of NGs!)

John Stumbles wrote:

or go to Heat Requirements section of

[Mike]

Sorry. I should have said that they are keeping the system vented

Richard (Mike!)

John Stumbles wrote:

or go to Heat Requirements section of

[Doki]

WB seem to be universally recommended. I know someone who runs a heating firm and it's what he puts in his own place.

[TheScullster]

"Mike" wrote>

Hi Mike

I had my heating overhauled 18 months ago. The DIY bit was that I thoroughly researched all elements with the help of this group and specified all aspects of the work. Also I had battled for 2 years before this, improving the existing system, replacing rads and eliminating pump-over etc.

Largely on the recommendation of this group I also fitted the WB 24Ri.

I have a 4 bed detached (a bit higgledy piggledy) 1970s place - not too well insulated yet :(.

Doing a detailed heat loss study I arrived at ~ 16Kw for space heating. Conservatively adding 20% for pipe losses and a further 3Kw for the HW cylinder gave 20Kw. So, as a worst of worst cases I could justify the 24Kw non-combi boiler rating.

Obviously you will be more interested in the general performance of the unit.

The only 2 issues I have had so far are:

Noise - this is the first fan assisted boiler I have experienced, so the general operational noise was a bit of a surprise. Also, some of the panels (particularly the bottom tray) are a loose type fit, so some annoying vibrations have had to be silenced.

Overheat - this is nothing to do with the boiler per se. The installers did not set up the by-pass valve properly, so it never actually by-passed. This led to extended over-running of the boiler and the blue alarm light flashing (until I found the problem).

At the time of install, I also had the heating zoned to separate upstairs and down to make it more controllable. Still haven't analysed bills to see how much gas this is actually saving!

HTH

Phil

[stuart noble]

The 241 junior is certainly noisy. We've sort of got used to it now but the high pitch of the fan was a bit of a shock. The cat didn't like it either.

The case isn't particularly well anchored, and I haven't found any way to stop the vibration .

The other annoying thing is that it has to deliver several litres of cold water before the burner lights up. Very frustrating if you just want to top up a bowl of hot water.

I expect these faults are common to all newer combis though

[Dave Plowman (News)]

Perhaps you should have looked at the Viessmann Vitodens 200. I reckon it's no more noisy than just the burner was on my old Potterton. The casing has sound deadening panels. The only time you really hear it is when it runs the fan at boost IIRC to vent the burner enclosure when first firing. Of course it's expensive - but then it's not something you replace every other year. Hopefully.

[RJS]

Surely not the case when used with a separate H/W tank? It is to be installed as a replacement in a conventional vented system with H/W tank and rads. Not as a combi boiler.

Richard