What size combi and make...recommendations

[ajay.parmar.uk]

Hi,

I've decided to replace the existing Vokera Linea (24kW) combi with more powerful unit due to:

1. Number of people in household increasing from 2 to 5

1. 2nd bathroom and additional bedroom being constructed into the loft.

Specification of original house is as follows:

3 Bedrooms 1 Bathroom (Bath & Electric shower)

After conversion:

4 x Bedrooms 2 x Bathrooms (Bathroom 1 = Sink, Toilet, Bath & Electric shower. Bathoom 2 = Sink, Toilet, 1 grohe Rainmaker thermostatic shower)

Based on experience, what would the recommendation be for:

1. Output of boiler
2. Manufacturer

The existing unit is wall mounted and therefore the replacement should ideally be wall mounted too.

Look forward to your input!

Thanks in advance

[David Hansen]

On 7 Mar 2006 08:59:52 -0800 someone who may be [e-mail] wrote this:-

Combination boilers are not particularly good when several taps are turned on at once, which is more likely with five people and two bathrooms.

I would install a hot water storage system, suitably sized to allow for the number of people, fed from the boiler. I would also look at a solar system to provide some of the hot water, possibly all of it in the summer. The ideal time to fit this is when work is being done in the loft.

[bobbymobile]

What you want is one of these:

has has a built in tank so you get stored water pressure from a combi boiler. You can run 2 taps at the same time.

Bob

[Doctor Drivel]

Which combination boilers are you on about?

Very poor advice.

The best performing wall mounted combi is the Alpha CD50 (5 yr guarantee). It will fill bath pronto and do two shower at the same time. It is stored water, and a two stage flowrate. When the stored water runs out it drops to a lower flowrate and "never" runs out of hot water. The recovery rate of the store is in minutes. They are rated two bathroom jobs.

There are many floor mounted combis (one-box solution) that deliver very high flowrates: Viessmann 333, Potterton Powermax. Ideal Istor (Ideal are yuk), Worcester-Bosch Highflow 440, ACV HeatMaster. The Gledhill Gulfstream can provide up to 3 bathrooms as long as the mains can supply the flow.

[Doctor Drivel]

> it has has a built in tank so you get stored water pressure from a

"Flow rate = 13.7 L/min "

"Engineered to meet increasing demands for superior hot water performance, Vaillant has launched the pioneering new aquaPLUS combination boiler with integrated power store. Thanks to the 15-litre stainless steel store the boiler delivers outstanding bath filling and shower performance, supplying over 170 litres of hot water (delta T 35°C) in 10 minutes."

The figures don't add up. 170 litres in 10 mins is 17 litres/min. Take away

15 litres because of the 15 litre storage vessel and that is 155 litres per 10 mins which is 15.5 litres/min. Then they say 13.7 litres/min, which is nothing special at all.

[Doctor Drivel]

>>> it has has a built in tank so you get stored water pressure from a

It is also an old design, still having rail burner. At over £1,000, I think best avoided.

[Dave Plowman (News)]

You really have no idea how much hot water is needed to fill a decent sized bath quickly, do you?

[Doctor Drivel]

What the hell is he on about? Sad isn't it. Very sad when people become so senile.

[David Hansen]

On Fri, 10 Mar 2006 20:17:30 -0000 someone who may be "Doctor Drivel" wrote this:-

The original poster can use a search engine to study your frequent and lengthy assertions about combination boilers and decide how much notice to take of them. While doing so they may want to consider whether one sort of boiler is ideal for all circumstances, as you frequently assert, or whether things are more complicated than that.

[Doctor Drivel]

Good advice.

A correctly selected combi can do the average British home and more. Read what I wrote...and stop babbling tripe and get to know something about them. It is not 1976 anymore.

[David Hansen]

On Sat, 11 Mar 2006 11:23:04 -0000 someone who may be "Doctor Drivel" wrote this:-

Yawn. Personal abuse, usually the resort of people with no better arguments.

Readers can read what I wrote. For a household with two people and one bathroom a combination boiler has many advantages and may well be suitable in most circumstances. However, for five people and two bathrooms a storage system will usually be more suitable, as it will cope better with the varying draw-offs which are likely in such a setup.

Anyone who doesn't consider these sorts of thing may well regret not doing so at their leisure.

[Doctor Drivel]

That was constructive advice. You know when you get abuse.

Wrong. Read what I wrote again. Read it hard. Istead of trying to make out you know it all, it would be better if you said, "thanks Dr Drivel, I never knew that".

[David Hansen]

On Sun, 12 Mar 2006 10:43:29 -0000 someone who may be "Doctor Drivel" wrote this:-

If you really think that then readers may feel they can make some deductions about you.

Ah, proof by assertion.

The bit of your posting that was not personal abuse is, "A correctly selected combi can do the average British home and more." That is simply an assertion. Reading it again or reading it hard (whatever that means) does not change it from being an assertion.

I don't know everything and I certainly have never tried to pretend that I do know everything. However, I do note others who have made such a claim.

AFAIR, in relation to combination boilers, you have yet to tell me something that I didn't already know.

[Doctor Drivel]

It is not assertion, it is fact.

It is alerting you to the fact.

Don't tell lies. If you about them you would not tell people to go tanks and cylinders in normal British homes. It is clear you haven't much of a clue.

[Dave Plowman (News)]

Dribble is a sad individual who hasn't any family and never uses a bath. So his idea of the performance of a hot water system is restricted to what he reads in adverts - and he doesn't understand how to interpret these. If he did - as he claims - specify such systems for clients he'd have been long out of business.

[Doctor Drivel]

The senility has really taken hold. The inane babble, the dribbling in his shirt, uncontrolled flatulence, and the rest. Sad but this is how he is. Sad but true. Please take pity.