Combi Boilers

[dave.c]

I have 3 bed det hse with traditional system and wall hung 20+yr old boiler in garage. Am upgrading only bathroom and would like dry loft and to use cylinder space in bathroom for mains pressure shower - I have 21.5l/min. Asked advice from 2 installers who I have used before and one said a "combi (approx £2800)" and the other said "megaflo and anyone who tells you different isn't telling it as it is (approx £6000)". Megaflo seems expensive and bulky - would prefer to keep my small garage for my car and stay with a wall hung. After some research on these forums I am now thinking that a combi storage is a reasonable compromise at a reasonable price - the advertising blurb sounds good - 200litres of hot water, filling baths in a few minutes which my missus likes, more than one tap on, quick recovery times etc. I have found AlphaCD50, Glowworm Xtramax and Saunier Duval Isotwin F35E as possibles. Glowworm would be my favorite as it seems to have good support. My questions are a) Would these do the job? b) has anyone had experience of or could recommend combi storage? c) they do not seem to be very popular despite seeming to give the best of both worlds - is there a reason for this? d) is there any way you can get reliabilty statistics for boilers?
I posted this on plumbing pages and Dan Robinson kindly responded - he didn't rate my choices and suggested Atmos in particular the Intergas Prestige (or Multi 24/80 which might have too much oomph for me). The reliability impressed me but the Multi looked v expensive by comparison. Would appreciate any other comments.

 

[gas4you]

If you only have one bath and shower then a normal combi will suffice. If you mainly have showers and occasional baths then a 31Kw will do. If you want baths more than showers then I recommend the 37kw versions as these give more flow.

I always fit Vaillant boilers. Their 31Kw gives 12.5 l/min hw and the 37Kw gives around 15 l/min. They also have now brought out a storage combi, the ecotec plus 937, which has 15 litres of storage, so doesn't come under the un-vented regulations, and blends this hot store with cold to make it go further. This gives about 20 l/min flow. It is in fact an 837 with storage added behind it.

Vaillant reliability is second to none.

Craig on here will recommend Worscesters and Paul Alphas, but there is little between the top makes.

Don't forget that any of these large combis will necessitate you having the gas supply form your meter to the combi increased in size as well to allow them to perform correctly.

The unvented cylinder option is nearly always the best performing system and will allow multiple hot taps to run together, but space as you say is a disadvantage as is price and needing a registered un-vented installer to fit it.