Advice please, changing our ancient Baxi back boiler to new combo boiler

[indieblack]

Just that really.

Our boiler just passed its last service and has 2 big water tanks (one of which is in our tiny bathroom) that we'd love to get rid of.

Any ideas re: cost (we're in London gulp), the process and suggestions for a good quality combi boiler would be brilliant.

Thanks

We replaced our ancient boiler and hot water tank with a combi and I really wish we hadn't. The water takes ages to heat up (instant it isn't, despite what we were told) and we waste tons of water waiting for it to run hot. I also really miss my airing cupboard!

I've a suspicion we had a bit of a cowboy plumber though, so other people might have had a better experience.

We are in a very similar position, but it's a house we just moved in to. The ancient Baxi Bermuda has been signed off as safe, but the plumber strongly suggested we upgrade to a combi, we also want new plumbing, rads etc. so the full job.

As we are about to go through a re-wire too, it seems to make sense to do everything in one hit. The house is 1950 built and all the plumbing and electrics are original.

Plumber is known to us through a family connection so is (hopefully) accountable. He is recommending a Vaillant combi, the higher wattage - we are in a 4-bed semi.

FWIW we were really happy with our Potterson Baxi combi in our old (smaller 3-bed).

My only reservation/worry is that the pressure might be inadequate, and how getting rid of the water tanks migh affect this. At the moment pressure isn't great. We are also replacing the mains supply pipe so maybe this will help.

I am yet to get a gas bill but we have the hot water/heating set to 'on' and the water is boiling as if from a kettle as soon as the tap goes on, 24/7, so I dread to think. This is the first time I have had a back boiler.

I would be similarly interested to hear others' experiences, good or bad!

We just replaced our very ancient boiler and paid 2k. Water tanks are still in the loft but have been drained and we will get rid of them eventually.

Our boiler was several feet high and floor-mounted, it was that old. It weighed a staggering 150 kg! North Sea gas reserves have been depleted thanks not to the general global picture, but to our old boiler... I think our new one is a Baxi. Our old one was hot water/heating or nothing, which was okay in the winter, but in the summer if we wanted hot water we had to turn on the immersion, which as you can well imagine ate electricity.

Water pressure is no different, and it heats up quick enough for us.

We have a high wattage boiler (decent-sized 4-bed semi) which hopefully will be able to cope with any additional shower we put in.

We were warned our equally old radiators might not withstand the power flush, but they've been absolutely fine. We already had thermostatic controls on them. One thing we really like is we have a wireless room thermostat/controls so we don't have to go anywhere near the new boiler.

Hi Indieblack,

I've signed up here to give sound impartial advice so hope I can help.

The two, but usually 3 water tanks you speak of are the Hot water cylinder, a tank above that is used to re-fill the cylinder and a third tank usually tops up the central heating supply as and when you drain/bleed radiators. Whilst many people will have differing opinions about combi boilers they are un-arguably more energy efficient. Yes, you can wait 10-15 seconds for the hot to come through but much of this depends on the location of the boiler and the location of your tap you have turned on. If you hadn't ran water from your existing cylinder recently, there too would also be a delay whilst the colder water in the pipes came through followed by the hot. Some combi boilers have built in mini tanks with hot water instantly available and some have a pre-heat feature but again dependant on the pipe run from the boiler to the tap will depend on the delays people often talk about.

We have experience of fitting both Worcester Bosch boilers and Baxi ones. At the moment we fit more Baxi's as the 7 year warranty and cheaper purchase price seems to be a factor with our customers. We have had no general problems with both boilers over several years.

Choice can sometimes be determined by space, will it fit in the kitchen cupboard, a loft space etc. People with back boilers such as the ancient but very reliable Baxi Bermuda have no choice but to relocate the boiler from the usual chimney breast location.

The main points of consideration other than location are size, is it suitable to run two thermostatic showers or a 4 bedroomed house etc. Also, your existing system will have lots of corroded particles within the heating circuit/water. This is due to normal corrosion of steel radiators, its what makes the water turn black when the system is bled or drained down. A good plumber/boiler engineer will consider flushing the pipework so that these particles don't cause problems to the sensors in your new boiler. This can invalidate the manufacturers warranty. Some people will fit a Magnaclean which in essence is an in-line Magnet to capture the corroded metal particles. This is fitted on the return flow so that the particles are collected before the water re-enters the boiler for re-heating.

I hope all this helps with your considerations but let me know if I can answer any further queries.

Kind regards,

Liam

"combi boilers they are un-arguably more energy efficient"

Except in summer, when they are just used for hot water.

Starting the boiler up and shutting it down dozens of times a day, every time a hot tap is turned on, is very inefficient.

I can agree with you there John, but i'm generalising in comparison to the much older boilers. The heating part of modern systems is not too indifferent from the older type boilers thus it is the heating of the hot water that has mainly changed. I agree, though far from perfect until something revolutionary is designed were stuck with combi's. Of course, system boilers are still available to heat up water cylinders but sometimes people want to free up the space. There are pro's and con's to all systems but I think the lack of needing cylinders, tanks, pumps and electronic valves over and above the boiler itself make combi's a winner, much less to go wrong theoretically and most people welcome the added space free'd up by the cylinder/tank removal.

Which have a great read up -
www.which.co.uk/home-and-garden/heating-water-and-electricity/reviews/boilers/page/features-explained/

Thanks

Ah, yes. certainly a modern condensing boiler is much more efficient than a 30-year-old iron boiler.

But efficient, modern, condensing boilers are not all combis.

Baxi are marketing a modern condensing back boiler as a direct replacement for their old back boiler, i.e. will sit in the fireplace with a modern looking electric fireplace frontage.

Finding a plumber who has experience of these is another matter. It seems much easier to jump on the combi bandwagon as far as I can tell.

Thank you all for your thoughts. We're hoping to upgrade our bathroom this year and have a separate shower cubicle in place of the cupboard with the water tank. So we'd like to do both jobs around the same time.

We have a hotchpotch of radiators so it sounds like the older ones would need replacing. We have room for a boiler in the kitchen but will need new piping I guess.

Any thoughts on likely cost?

Thanks again!

run your kitchen cold tap into a bucket, time it, see how many litres per minute you get. Do the same at your garden tap or utility room if you have one.

I am waiting for my quote at the moment!

I am getting approx 12 litres/min at the kitchen tap. That's with the old lead supply pipe which we are planning to replace...if that makes a difference?

'mmmm

12 lpm is rather poor. Have you had the water co out to test your drinking water for lead? There may be a lead replacement subsidy, and they may replace their lead pipes feeding your house as well, which will make it easier to connect and also improve flow. Get the test done as quick as you can, they may be slow to make an appointment, and if they don't arrive before you replace the pipe, no subsidy.

Get at least a 25mm, or preferably 32mm, blue plastic pipe, all the way from the pavement to your new boiler (or cylinder), with full-sized stopcocks. There is hardly any price difference between 25mm and 32mm pipe, and the labour is the same (the stopcocks are quite expensive though).

I am sure that will make a vast improvement to your flow.

btw if you have a modern boiler, a new water supply pipe, and an unvented cylinder, you will have unsurpassed hot and cold water (better than any combi)

Thanks PigletJohn, I'll get on to the supplier. Still waiting for that quote :S