Which Combi Boiler

We’ve got an option to replace our combi boiler at a vastly reduced price through one of the energy schemes.

Our current boiler is a Potterton PromxHE Plus 28, I assume it will be replaced with a similar rated boiler. It feeds 11 radiators 6 downstairs, 5 up and a shower (& bath & taps).

The default boiler offered on the scheme is an Ideal Logic model though I’m not sure yet which one. We have the option to install any boiler if we pay the difference and where told £200 for an equivalent Worchester.

Are there better and worse manufacturers when it comes to combi boilers, any one we should consider of any other. I am conscious that I don’t want anything with a hot water flow rate less than our current boiler and will check this against what we are offered.

Don’t underspec the HW capability of a combi.

I have always overspecced in the past. Where a 28kw was recommended I always went with a 32.

Worcester Bosch were recommended to me by several plumbers.

All manufacturers produce a range of boilers sized to suit your (home) requirements. Our previous house and this one, we used Worcester Bosch on recommendation of the heating engineers and don’t have any complaints.

The latest one is all wi-fi’d and controlled through a Bosch app on my phone. WiFi rad valves allow different temps in each room and the boiler varies water temp to ‘top-up’ heating makng it more efficient or summink. Only installed in the summer so cant compare yet, but warms the house well.

But anyway your heating engineer should advise whats best and affordable.

Edit – and what Gobuchul says, we oversized so we can run both showers if necessary

i’ve got an ideal logic something or other. been in nearly three years and no issues at all.

7 year warranty but only if you get it serviced annually.

The default boiler offered on the scheme is an Ideal Logic model though I’m not sure yet which one.

There’s a reason for that.

I’ve been involved in several large scale boiler replacement projects ( maybe 10,000+ installs all told) and every time it’s been an Ideal Logic boiler that we’ve fitted.

The procurement exercises have alway turned out the same with the Ideal boiler offering the lowest cost, longest manufacturer warranty and acceptably low failure rate to make it a no brainer.

They are perfectly good boilers but designed for exactly this sort of scheme. It’s a numbers game. If you’re buying 10,000 boilers, get an Ideal Logic.

Having said that, I have 2 Worcester Bosch boilers in my house. The numbers are different if you’re only buying 1 or 2

They are perfectly good boilers but designed for exactly this sort of scheme. It’s a numbers game. If you’re buying 10,000 boilers, get an Ideal Logic.

Having said that, I have 2 Worcester Bosch boilers in my house. The numbers are different if you’re only buying 1 or 2

And we’re only buying one…

Comparing on screwfix on 30-35Kw HW boiler it appears that (based only on HW flow rate)

Viesmann / Ideal > Worchester > Valient

The Ideal boiler all appear to have 24Kw for the radiators where the other makes are more aligned output radiator/hot water.

Naively from my understanding with 11 radiators and one shower (2 heads, waterfall + standard) best for me looks like the 35/24Kw Ideal. There is a comparable HW flow rate Viesmann but it has a 35Kw radiator feed which seems way overkill for our house.

7 year warranty but only if you get it serviced annually.

The Ideal warranty is now 10 or 12 years depending on the boiler, mine is 10 years and had the first service done this year and was £72 so not that bad.

I went for the boiler that had the longest warranty, at the time that was Ideal, not sure if Worcester Bosch have increased theres from 7/8 years

Had a new WB fitted this year – had WB before and some digging around convinced me to go with them again.

12 year warranty if you get the magnetic filter thing and use an WB accredited fitter.

As above – size for hot water requirements, rather than central heating (unless you live in some mansion and then prob wouldn’t want a combi anyway).

If it is first time you’ve having a condensing boiler, then pay attention to when they tell you how big the plume might be. Double that. This time of year you can see which houses have condensing combis – that’ll give you some idea.

We run lot of residential and commercial lettings, and now we exclusively fit Worcester Bosch when things need replacing. Best for reliability, parts, ease of repair. They have a great warranty service and just generally make my job much easier.

Worcester Bosch every time. Fitted an Ideal in a rented property and had nothing but issues with it (now replaced it with a Bosch!)

Worth the extra in my opinion

Mine is Ideal Vogue C32 and was installed 4 years ago and as oikeith above I went for the longest warranty boiler (10yrs at time, now 12 I believe). Ideal had a bad rep yrs ago which still carries baggage for them, but apparently some yrs ago they poached some Wiesmann people who redesigned the whole range. I’ve had no issues

Just pricing boilers up, looking at a Vailant eco fit pure 830 for £2k fitted, this if for a house with 8 radiators
Good?

can’t comment on the boiler itself (just had an ideal fitted) but the vaillant guy who came out to coax my old boiler along was an absolute diamond. it was 13 or so years old, they came out on a ‘pay ‘x’ (400 quid?) and we’ll fix anything we can’ to the boiler i’d neglected to have serviced since a friend of a friend’s dopey electrician mate had blown up a control board on it costing me 200 quid at the time. the control board was the first thing replaced, along with various gaskets to address a water leak no-one else had been able to sort, and pretty much replaced everything possible including a gas valve that he said was way over-specced (and i would presume mis-matched) for the output.

he left, i went back to work, then about 3 hours later he called me and asked if i was at home. he was worried he hadn’t torqued up some bolts and would worry about it all weekend. i met him at home, he checked the bolts, which he had torqued.

if a manufacturer is giving a 12 year warranty they have to be pretty confident either that you’ll never service it according to schedule or that it is good for 15 years min. i’d say. or both. :D

A plumber offered a price on Ideal / Worcester and Valient boilers. Same spec but each model was a £200 increase. In his opinion there was no difference between them so we went for the ideal (cheapest) and its been fine. 35kw for 3 bed house, one bathroom and downstairs toilet.

I fitted a WB in our previous house – great boiler, PIL’s same boiler – 12 year old now and no problems apart from the condensate drain occasionally freezing in winter and backing up.

Would consider Worcester as they are future proof and are easily switched to Hydrogen by changing a part.
Will fit these in any properties now for that reason.
Up until this always fitted Ideal. Great service and back up

Ive fitted both Ideal and Worcester for a while…

Worcester were head and shoulders above the rest of the market for many years, the rest have now caught up in the main. The new Worcesters are no great shakes IMO.

Ideal were terrible for many years but since the redesign are really solid. The Vogue is a great boiler… they are all well priced I think.

Thats my 2ps worth.

With hydrogen I can see whole boiler or parts swaps being the tip of the iceberg… all that leaky mangled gas pipe from the meter to the boiler is where the fun is gonna start…

molecular weight…
CH4 19 g/mol
H2 2 g/mol

so maybe 8 times more susceptible to leak.

Its only going to be 8-10% H2 though so not really much of an improvement in emmssions.

Good way to keep installing gas boilers in new builds after 2025, lots of hydrogen ready stickers, job done!

OP why replace? Having issues, ageing?

Nothing wrong with the boiler.

Whatever way they’re running the scheme we’ve been told that they need to meet some energy efficiency saving to qualify. They can achieve this by replacing a boiler that more than 8 years old and adding underfloor insulation (I think this is a fiddle to be honest – I reckon at best a new boiler will be a couple of percent more efficient than our current one).

Our boiler is 9 years old. We’ve been intending to do underfloor insulation in the house for a couple of years but never gotten around to it. We were expecting it to cost around £300. We’ve been told £500 for boiler + insulation. Seems a no brainer.

We changed boilers a year ago, we went with a Baxi over the equivalent WB and saved £400.00 . No problems so far .

This thread is great timing, looking at quotes for a new combi boiler atm. Current boiler is a 20 year old WB, couple of parts on it need replacing so considering a new one. Swaying towards a new WB, the fact that the current one is 20+ years old, been trouble free and still has spare parts available (at a decent price) so I at least have the choice between fix and replace

Just pricing boilers up, looking at a Vailant eco fit pure 830 for £2k fitted, this if for a house with 8 radiators
Good?

We have an older version of that which was 2yo when we moved in, so now – gosh – 10yo. Always been very good, several indie gas people, have said it’s a good boiler well made, still looks brand new with all the digital readout stuff.

The only problem we’ve ever has was a washer failure on the top up inlet tap after it was constantly on-off to fit a couple of new rads, but dry washers tend to do that if the taps are turned / left closed for a while. Valiant came an fixed it free becuase the prior owner had taken out a 10 year warranty on it.

Out of interest, how good are modern combis in terms of water pressure to showers etc? I’ve been in a couple of houses in the past which were particularly pathetic, and currently have an unvented system which is fairly good.

Most combi’s need a min flow rate. We normally make sure we upgrade the line coming in, in case its the old lead or some other crap. But honestly they are few and far between now, most houses have been done.
Anyway min flow rate will help, but you need to ask your plumber..

how good are modern combis in terms of water pressure to showers etc? I’ve been in a couple of houses in the past which were particularly pathetic, and currently have an unvented system which is fairly good.

I might be talking out of my arse here and I’m sure I’ll get told if I am, but I was advised to go next size up on my combi for the hot water flow rate. I’ve only got a small house and was assuming the smallest Ideal Vogue C26 but was persuaded by the plumber on the C32 for purely that reason. My shower flow rate from the combi is very good altho the house water pressure is also very good if that’s a factor. It’s also pretty much instant heat if the boiler is already on.

Out of interest, how good are modern combis in terms of water pressure to showers etc? I’ve been in a couple of houses in the past which were particularly pathetic, and currently have an unvented system which is fairly good.

Ours is excellent, probably the best domestic shower I’ve ever used compared to pumped vented cyl, or electric. It’s even great temperature and reasonable pressure when a tap is being run elsewhere. We also overspecced for future proofing. I’m sure it’s entirely dependent on your supply though.

We ripped out our WB as it broke down most years, put a BAXI in must be about 10 years ago and it’s been great, but for hot water and showers always put the biggest one in or have poor hot water with more than one person using it.

That’s interesting, our supply was replaced a while back and is pretty decent (good enough that I need to install a balanced cold supply for our shower as the direct feed is too powerful). A slightly overspecced combi might be the way to go, as the tank may need replacing at some point. Thanks.

can anyone recommend a boiler fitter? out boiler is on the way out, and just needs a straight replacement…most local plumbers are booked up for months, but this sight says it has availability?

iheat.co.uk

but i’m always dubious about using websites for this sort of thing,

has anyone got recommendations?

Ideal Vogue 32 here, can have both rain showers on, only a very small difference in flow compared to just one running.

@martinhutch probably also worth pointing out that I’ve got the boiler hot water temp set fairly low, so when running the bath or washing up there’s no need to mix much cold water. So likewise the shower water will probably be nearly all from the boiler. My litmus test was my Ozzy Bro in law who has whinged about Brits and our pathetic electric showers, he was happy.

We needed a new combi-boiler to replace the tank system and our plumber recommended Ideal or Vaillant. We went with the Vaillant EcoTech Pro 28 and it’s been brilliant. Very quiet, hot water comes through quickly, easily enough pressure to feed our shower and heating just work. Been in 3 years now and had it serviced the other week (as per the warranty requirements) and out plumber said it still looked like new inside.

When we had it fitted with also had a full system flush and radiator clean to prevent any crap from the old system clogging up the new boiler and three years later the water is still pretty clean. Would recommend getting this done at the same time.

As above – size for hot water requirements

+1

We oversized our boiler (according to the plumber) but it means really good pressure in the shower, or adequate pressure if running two showers at the same time. The heating modulates right down so I don’t think there are any disadvantages beyond a small additional purchase cost.

Out of interest, how good are modern combis in terms of water pressure to showers etc? I’ve been in a couple of houses in the past which were particularly pathetic, and currently have an unvented system which is fairly good.

We fitted a 50kw Worcester Bosch recently as part of our house refurb. It heats two zones of underfloor heating, 11 rads, five towel rails and hot water.

The boiler is pretty much silent. Water pressure in one shower is excellent, proper power shower. Its good pressure for two showers and okay/not great if three are going. This isn’t a problem though as no reason why three showers should be running at the same time.

Our builders and plumber both said that they use WB by default and only use anything else if the customer is insistent.

Boilers are remarkable really, the amount of use they get and manufacturers give 8 – 12 year warranties. That speaks volumes about how well engineered they are.

What are other peoples thoughts about getting boilers serviced? I didn’t get my old one done for about 8 years and when it was done I’m sure the service engineer just blew the dust of it and then put the cover back on. I then started using BG boiler cover as it was quite good value when you consider you get a service as well. I now need to look at this again to make sure the warranty stays valid. What service interval do others go with, if at all?

Some combi boilers can be de-rated for smaller houses, so if you need decent hot water flow but find that it’s oversized for the heating, it might help.

Our WB Greenstar 35+ has just been serviced again. 15 years old and it’s only ever needed one expansion tank replacement and a bit of silicone on the condenser trap connection thread. Will buy another when this one eventually dies.

Thanks for the info – our conventional boiler (BAXI) is 12 years or so old, and still going OK (changed the expansion tank a couple of weeks back), but we want to replace the bathroom next year and ditching the tank at that point would potentially free up some extra space for a bigger shower.

What are other peoples thoughts about getting boilers serviced?

for a lot of people it will be a requirement of the warranty

I was going to get a Viessmann combi boiler but lack of recommended fitters in my area put me off. I ended up with Vaillant Eco Tec Plus 32kW paired with vSMART thermostat and Fernox TF1 omega filter. It’s been few years since I got it and it’s been fantastic. Highly recommended. It comes with longish warranty (yearly services required).

I’m having an Ideal Max Combi with a 10 year warranty fitted tommorow. Yearly service to honour the warranty will be about 60 quid.

We’ve currently got an old 30kw Saunier Duval which every gas engineer who looked at it said was a bag o sh1te. Its been brilliant and chugged away for nearly 18 years and still going. Simplicity was probably what gave it longevity. A really basic combi. But what made a massive difference to our house was changing the old radiators to modern ones. We were p1ssing money away with those old ones and the lack of convected heat.

I could of let it carry on but just thought the boilers gonna go soon so the big bill will land. Be nice to have a wireless thermostat without shouting to the kids upstairs to override the timer!

I’m guessing they’re all much of a muchness in the similar price bracket and every gas engineers got an opinion on one!