I've now, after much deliberation, narrowed my search down to a Worcester Bosch 42CDI. My objective is to obtain a reliable boiler with plenty of hot water for the young family in my 3 bed medium size home which is efficient. Is this a good choice after discounting other options? Would you pick another manufacturer/ model? I'm adding the digital opimiser programmer (DT10RF), divertor valve and magnaclean options- are these good choices?
Worcester Bosch 42DCDI, is this a wise move?
- Thread starter Evie2007
- Start date
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Make sure your incoming mains water pressure is sufficient to do justice to the claimed hot water flow rate of this boiler. Likewise gas pressure at your meter will need to be adequate and pipe sizing for the gas will also be critical on this gas hungry monster.
Your installer should check this before any decision is made.
Your installer should check this before any decision is made.
27cdi suitable for 1-3 bed & 1 bathroom
30cdi suitable for 1-5 bed & 1 bathroom
37cdi suitable for 1-5 bed & 1 bathroom & 1 ensuite
42cdi suitable for 1-6 bed & 2 bathrooms
you can down load the tech specs from
http://www.worcester-bosch.co.uk/installer/literature/product-guides-and-brochures
and these will give you further info for aninformed decision
30cdi suitable for 1-5 bed & 1 bathroom
37cdi suitable for 1-5 bed & 1 bathroom & 1 ensuite
42cdi suitable for 1-6 bed & 2 bathrooms
you can down load the tech specs from
http://www.worcester-bosch.co.uk/installer/literature/product-guides-and-brochures
and these will give you further info for aninformed decision
Gas hungry monster
From my reading of the op's post it sounds as though he's thinking of a 40 CDI conventional or a system boiler NOT A COMBI.
As a matter of interest this boiler in common with the entire range down to the 30 CDI has a heating output of 30KW and the 42CDI only produces about 5 litres a minute more hot water than the 30 CDI and 2 litres a minute more than the 37 CDI and while it's true that gas pipe size is critiical for tis boiler and indeed the 37 CDI the boiler is hardly a 'gas hungry monster'.
Also, these boilers are some of the very few combi boilers that condense on hot water.
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Not sure how you work that out.
The OP's previous post confirms it's a combi they're after.
And it's gas flow rate according to the manufacturer is 30% more greedy than a 30cdi.
You might recall you also had something to say yourself about the 42cdi on a previous posting:
//www.diynot.com/forums/viewtopic.php?t=119210&postdays=0&postorder=asc&start=15
Why do you think a combi boiler is the best solution?
There is no point buying a large combi if the cold water flow rate and pressure is not adequate. The 42CDi needs a flow rate of at least 15 litres/minute. If the pressure is not high enough, the flow rate from a tap/shower will depend on how many are in use at the same time.
You say you have a 3-bed medium size house, but WB recommend the 42CDi for a six bed house with 2 bathrooms!
The problem you may find is that, while the boiler is fine for hot water, it is massively oversized for central heating. The minimum CH output is 9.3kW and you may only need this amount - depending on how well your house is insulated.
You should find out the CH requirement by using one of these calculators:
Sedbuk Boiler Calculator
EST online boiler calculator
I would also suggest that you work out the total output of your radiators by using the Stelrad Elite Catalogue as a guide.
Post the results for further advice.
never use Worcester as first choice but think the 42 is too big for your needs.
we use the vaillant ecotec 831 & 837 regularly, most customers have the 831 and 10% opt for the 837 because they have teenage children/large useage never had a complaint about water delivery on any. if your set on a worcester then i think the 37CDi would be more than man enough for the size of house your in.
we use the vaillant ecotec 831 & 837 regularly, most customers have the 831 and 10% opt for the 837 because they have teenage children/large useage never had a complaint about water delivery on any. if your set on a worcester then i think the 37CDi would be more than man enough for the size of house your in.
It's your use of "diverter valve" which is causing confusion. COmbis have them internally, no need for further mention, system boilers can have then added if you have an external HW cylinder...
COmbi size is determined by your HW requirement. IF you have adequate supply, AND a monster shower OR run a lot of baths OR want to supply more than one outlet simultaneously, then a 42kW combi is suitable.
On the heating side it would short-cylcle quite a bit, but that shouldn't cause problems.
Gas supply shouldn't be a problem either, as long as you have fat enough pipe doing it. You'll almost certainly need at least 28mm, depending on distance.
Worcs boiler reliable?? Not particularly, but the telephone customer service is good.
I've just taken out three worcs boilers, from one house, at under 4 years old. Their owner was fed up with repeated breakdowns. Two Vaillant 42s went back in.
COmbi size is determined by your HW requirement. IF you have adequate supply, AND a monster shower OR run a lot of baths OR want to supply more than one outlet simultaneously, then a 42kW combi is suitable.
On the heating side it would short-cylcle quite a bit, but that shouldn't cause problems.
Gas supply shouldn't be a problem either, as long as you have fat enough pipe doing it. You'll almost certainly need at least 28mm, depending on distance.
Worcs boiler reliable?? Not particularly, but the telephone customer service is good.
I've just taken out three worcs boilers, from one house, at under 4 years old. Their owner was fed up with repeated breakdowns. Two Vaillant 42s went back in.
The reason i selected the divertor valve was that this was recommended on the WB site to utilise the fall back temperature facility on the DT10RF programmer i.e. doesn't let the house drop below a pre-selected temerature even when the boiler is pre-set for off on the 7 day programme. Is this standard on most boilers to have the fall back setting?
I'm now torn between advice, although gratefull for it of course!!
Taking into account the advise i should go for either the Valliant 831 or the Worcester 37CDI? Where would most peoples votes go????? The reason I sway for the Worcester is that the DHW flow rate is 15.1 l/m where the Vlliant is 12.7l/m- would I notice the difference in daily use i.e. water volume at the shower or running a bath? Who has the best reputation for reliability?
I'm now torn between advice, although gratefull for it of course!!
Taking into account the advise i should go for either the Valliant 831 or the Worcester 37CDI? Where would most peoples votes go????? The reason I sway for the Worcester is that the DHW flow rate is 15.1 l/m where the Vlliant is 12.7l/m- would I notice the difference in daily use i.e. water volume at the shower or running a bath? Who has the best reputation for reliability?
You do not seem to have understood that the flow rate outof the boiler is determined by the flow rate into the boiler; and this is determined by the flow rate from the cold water mains. You can't produce a flow rate of 15 litres from the boiler if the mains flow rate is only 10 litres.
You must get your flow rate checked first before choosing your boiler.
If you need two outlets running at the same time, e g the cold tap in the kitchen and the shower, you need to get your pressure checked as well.
I DO understand and will get this checked, i'm assuming until then that the flow rate is suitable for both.
That's good to know.
I think you are concentrating too much on the HW side and overlooking the CH side. You should use one of the boiler sizing calculators, as well as the Rad data, I gave links to and post the info.
if you are doing a comparison then you need to do a proper one as the 837 vs 37CDi gives 15.2 litres vs 15.1 litres
personally think the 837 is superior and you can program warmstart if you fit the 140 timeclock or the weather comp
There's logic to the madness! The 837 is too deep for the kitchen unit it's going in hence the selction of the 831. It's therefore a matter of what is the best and most reliable boiler between the V 831 and the WB 37CDI, your guidance would be much appreciated?
Not much between them I would say.
Customer service and length of warranty might make a difference in the end.
Customer service and length of warranty might make a difference in the end.
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