Combi boilers?

Box Brownie

Box Brownie

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Hi all

We are used to having a conventional boiler i.e. one with a system that includes a hot water tank.

However, looking at the potential of using a Vaillant combi boiler........?

So, looking for any user insights/experiences please for those with combi boilers?

TIA :)
 
We just got a new boiler fitted to the house we recently bought. It had an existing combi and we replaced it with a Worcester Greenstar 8000 and the Easy Control setup.

I sit very close to the boiler cupboard in my home office and I have no idea when it kicks in as it is so quiet. It does everything I expect of it and I have seen a reduction in our usage of a significant amount over the older boiler. Hot water is available in seconds and the heating can be programmed which is very useful and will save us a lot of money.

The warranty is 12 years.

I had a Worcester combi about 20 years ago and was very happy with it.
 
We went to combi 14+ years ago now on our second boiler. No issues just make sure the one you choice is powerful enough for your house. We have always gone for Worcester Bosch boilers.
 
we have a vailant eco tec pro 28 and its been rock solid for 10 years since installed
yeah its had a new diverter valve and its pressure vessel pumped up a few times i think they are good combi boilers.
benefits for you is not heating water you don't need in a tank assuming you just have one bathroom / shower and the water will not be as hot as scalding hot tank water can be
 
moggi1964 said:
We just got a new boiler fitted to the house we recently bought. It had an existing combi and we replaced it with a Worcester Greenstar 8000 and the Easy Control setup.

I sit very close to the boiler cupboard in my home office and I have no idea when it kicks in as it is so quiet. It does everything I expect of it and I have seen a reduction in our usage of a significant amount over the older boiler. Hot water is available in seconds and the heating can be programmed which is very useful and will save us a lot of money.

The warranty is 12 years.

I had a Worcester combi about 20 years ago and was very happy with it.
Click to expand...

Brentor said:
We went to combi 14+ years ago now on our second boiler. No issues just make sure the one you choice is powerful enough for your house. We have always gone for Worcester Bosch boilers.
Click to expand...

Mr Bump said:
we have a vailant eco tec pro 28 and its been rock solid for 10 years since installed
yeah its had a new diverter valve and its pressure vessel pumped up a few times i think they are good combi boilers.
benefits for you is not heating water you don't need in a tank assuming you just have one bathroom / shower and the water will not be as hot as scalding hot tank water can be
Click to expand...
Thanks all for the insights.

It is a 3 bedroom house and needed for both heating & hot water.

Also, with the conventional system we have the much used airing cupboard......I have read of/seen on the TV (a while back?) that a suitable arrangement is to a low wattage 'background' heater in the cupboard to provide the required heat for airing. How do you guys handle that need?
 
We have a Worcester Bosch Greenstar system boiler, our daughter has a Worcester Bosch combi. They are both approaching 10 years old now; the combi has been a load of trouble, they have had it fully rebuilt twice during the 7 year warranty period. It has broken down at least once a year since installing. By way of contrast we have had one problem with our system boiler which was fixed under warranty.

We both used the same installer. When discussing our differing experiences with him he said the combi boilers were a lot more complicated and less reliable.
 
Make sure you have sufficient water pressure at all times - depending where you live high load / low pressure times are weekday mornings, Saturday morning and often all weekend.

We ended up having our incoming main replaced (was a thin furred up lead pipe - house built in 1948) as the problem got so bad that often we couldn't shower at times of lowest pressure.

HTH

David
 
Ours is very old now but it still has the same little foible it had on the day they put it in.

The issue is that when I turn the hot tap on it takes quite a time to run hot and if I turn it off I'd have to wait again so when washing up I tend to leave it on a weak stream to try and keep it ticking over and this is what the installers recommended on day one but even then after a bit it'll very probably run cold and then quite a bit later hot again. The thing can't be trusted to run a bowl of hot water without being watched as if I left it it'd run cold and I'd end up with a bowl of tepid water. I have to keep swinging the tap away from the bowl so it doesn't spoil the hot water and swing it back again when it runs hot again.

For some reason it does a bit better with the shower if you get the flow exactly right. Get it a bit wrong and you'll be enjoying a nice hot shower which will go warm and then cold and then take an age to run hot again. It's gone faulty a few times and been repaired and they always say it's working ok.

It is very old though so hopefully the newer ones aren't like this but honestly there are times when I wish we still had a hot water tank as at least then I could fill a bowl with hot water or have a shower without this performance.
 
broc said:
We have a Worcester Bosch Greenstar system boiler, our daughter has a Worcester Bosch combi. They are both approaching 10 years old now; the combi has been a load of trouble, they have had it fully rebuilt twice during the 7 year warranty period. It has broken down at least once a year since installing. By way of contrast we have had one problem with our system boiler which was fixed under warranty.

We both used the same installer. When discussing our differing experiences with him he said the combi boilers were a lot more complicated and less reliable.
Click to expand...

Yes. The plumbers I have spoken to about this and personal experience says that combis don't last as long as conventional. Nice when they work, but at the end of your 7 year warranty you may well need a new one.

What you really want is a pressurised hot water system :)
 
This reminded me of my time in Kazakhstan where they had free hot water piped in, no boiler, just hot water when you turned on the tap :D
 
Are the government not trying to phase out combi boilers and get you to have a heat pump instead ???
With the rising cost of gas I think we might go that route if our combo goes T**ts up.
 
Had mostly good experiences with Vaillant combis. They come with a 10 year warranty but that does depend on you having it serviced annually by an approved agent to keep the warranty valid. They’re generally very reliable but a fitter told me they do have a weak spot, which is the expansion vessel which fails over time. Sure enough the one in the boiler my mum has went at 8 years old. It’s not a particularly expensive fix though, a new vessel was just under £300 fitted. (You notice it by the boiler pressure dropping unexpectedly).

One thing to note about putting a combi in… you can’t also have a pumped/power shower as the boiler can’t keep up with the speed of the water flow. So if your shower pressure is low without a pump you’d just have to live with it.

And @woof woof, some modern combis have a preheat tank that keeps a supply of heated water ready so you don’t get that issue. It does sound like you either have a very long pipe run to the kitchen tap, or it might be throttled down somewhere with a valve or it could even obstructed somewhere? It certainly doesn’t sound normal to me, it should run hot pretty quickly.
 
boogie man said:
And @woof woof, some modern combis have a preheat tank that keeps a supply of heated water ready so you don’t get that issue. It does sound like you either have a very long pipe run to the kitchen tap, or it might be throttled down somewhere with a valve or it could even obstructed somewhere? It certainly doesn’t sound normal to me, it should run hot pretty quickly.
Click to expand...

It's a very short run to the kitchen tap as the boiler is in a cupboard under the stairs directly outside the kitchen. It's a longer run to the bathroom.

As above, it's been like this since day one and the installers demonstrated the best way/flow to keep the flow hot. I have questioned the guys who've been to fix the various faults we've had but they've all given it a clean bill of health. I may be wrong but I've just assumed it's because it's early combi technology and just frustrating and not very good if you want a bowl of hot water. But, given the cost of a new one we'll very likely struggle on until we have to replace it.
 
My boiler blew up last year it was leaking from every joint and was 27 years old so I decided to give up ( all this just as the winter started) I used boiler central and decided on a Worcester Bosh with them having a good reputation, 5 days later it was fitted and working fine as it's done ever since. British Gas gave me an appointment to see them in 6 weeks and some of the others were even worse. I would have been looking at no heating or hot water for I'm guessing 10 to 12 weeks with the others. I looked at Vaillant but they were quite far down the ratings listing. (I have no experience of them myself) Mine runs the shower fine ( straight off the boiler) and doesn't vary with heat when other things are used.
( I intend to fit a Electric shower as I always like a back up just in case one dies)
 
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I wouldn't have another Vaillant boiler, our is 12 years old and has needed repairs around every 18 months, Vaillant customer service is rubbish.
 
Nikon f1.8 said:
Are the government not trying to phase out combi boilers and get you to have a heat pump instead ???
With the rising cost of gas I think we might go that route if our combo goes T**ts up.
Click to expand...
I saw a report recently that said the majority of UK homes have radiators that are too small for heat pumps. So you have to add the cost of swapping all the radiators, a figure of £30k was mentioned for the whole job.....

heatingnewsjournal.com

Heat pump costs soar because Britain's radiators are 'too

"I sought advice from a heatpump professional who stated the expense of setting up an ideal heatpump and changing all the radiators is practically £30,000. My home was integrated in 1976, it is
heatingnewsjournal.com heatingnewsjournal.com
 
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We have just replaced an 18 year old Vaillant combi boiler with a new Baxi condensing boiler.
Nothing wrong with the Vaillant but it was old and would soon be in need of some expensive repairs and would need replacing at some point so we opted for a new one .
The new one is a lot more efficient than the old one as shown by a comparison of gas consumption.
One thing to note the old boilers used 15mm gas supply the new ones need 25mm so you need to take that into account.
 
Had my Vaillant for a dozen years or so, did end up with a few problems (leaking pipe and blown expansion bladder ) and replaced it with a Viessmann which so far has been excellent.

Do lots of research, just because some makes are popular (especially with installers) doesn't meant they are the best.
 
Installers can get bonus points(payments) from merchants and will often plug a certain make as it earns them cash.
 
My first experince of a Combi was back in 2005, when I got my first home of my (our) own. We've moved house twice since and each house has had a Combi. I love them, more or less instant hot water and only heats basically what you need, save for what sits in the pipes. the central heating gets warm quickly too.

We did have an enforced house move in 2014. We had a leak at home from under the bath and it basically wrecked our floors and walls. We moved to rented accomodation, it had a storage type boiler with a tank, that you had to heat to get hot water, which could take some time. It was a remote house and that boiler was electric. We had to leave it running for hours to get hot water as it was a storage tank that had to be heated. The meter was a blur when it was on. The problem with a storage tank for us was the time it took before you got hot water and also any you don't use, might go to waste.

I was glad to get back to our Combi after that.
 
Nikon f1.8 said:
Are the government not trying to phase out combi boilers and get you to have a heat pump instead ???
With the rising cost of gas I think we might go that route if our combo goes T**ts up.
Click to expand...
Gas boilers will be banned in new builds only from 2025.
I won't be replacing my gas boiler with a heat pump any time soon, or ever for that matter.....
 
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Box Brownie said:
Also, with the conventional system we have the much used airing cupboard......I have read of/seen on the TV (a while back?) that a suitable arrangement is to a low wattage 'background' heater in the cupboard to provide the required heat for airing. How do you guys handle that need?
Click to expand...
We no longer have an airing cupboard, no need as we rely on the tumble drier, no need to air. We were grateful to have to space left by the airing cupboard which was turned into a shower.
 
JonathanRyan said:
Yes. The plumbers I have spoken to about this and personal experience says that combis don't last as long as conventional. Nice when they work, but at the end of your 7 year warranty you may well need a new one.

What you really want is a pressurised hot water system :)
Click to expand...
Pressurised hot water systems are not suitable for all houses though....
If a decent combi is installed you won't need to replace it after 7 years.
My experience selling boilers is that many combi's last for 15 years +
Conventional boilers are simpler as the pump/valves etc are external to the boiler and are generic, whereas in a combi they're built in and model specific.
 
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troutfisher said:
One thing to note the old boilers used 15mm gas supply the new ones need 25mm so you need to take that into account.
Click to expand...
The new combi boilers require 22/28mm depending on the output of the boiler, the length of the gas run and how many other gas appliances you have...
 
Went for an Ideal Vogue for our current boiler, deciding factors were stainless exchange, Opentherm support and most importantly a low minimum output for the 32kw maximum output.
 
woof woof said:
Ours is very old now but it still has the same little foible it had on the day they put it in.

The issue is that when I turn the hot tap on it takes quite a time to run hot and if I turn it off I'd have to wait again so when washing up I tend to leave it on a weak stream to try and keep it ticking over and this is what the installers recommended on day one but even then after a bit it'll very probably run cold and then quite a bit later hot again. The thing can't be trusted to run a bowl of hot water without being watched as if I left it it'd run cold and I'd end up with a bowl of tepid water. I have to keep swinging the tap away from the bowl so it doesn't spoil the hot water and swing it back again when it runs hot again.

For some reason it does a bit better with the shower if you get the flow exactly right. Get it a bit wrong and you'll be enjoying a nice hot shower which will go warm and then cold and then take an age to run hot again. It's gone faulty a few times and been repaired and they always say it's working ok.

It is very old though so hopefully the newer ones aren't like this but honestly there are times when I wish we still had a hot water tank as at least then I could fill a bowl with hot water or have a shower without this performance.
Click to expand...
What make/model do you have?
The kitchen sink may be closest to the boiler but may not be the shortest run. It depends on where it's been connected to the hot water pipework when it was installed.
 
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Box Brownie said:
Hi all

We are used to having a conventional boiler i.e. one with a system that includes a hot water tank.

However, looking at the potential of using a Vaillant combi boiler........?

So, looking for any user insights/experiences please for those with combi boilers?

TIA :)
Click to expand...
If replacing a conventional boiler with a combi, I'd check the cold mains water pressure/flow.
I'd also check the current hot water flow.
Assuming the cold mains pressure/flow is good enough I'd suggest getting a combi that at least matches the hot water flow that you're used too.
A lot of complaints regarding combis performance tend to be around hot water flow rates and a lot of companies don't bother testing flow rates etc and fit a boiler that's not appropriate for the size of the house or the needs of the occupants.
I sell boilers for a living and I have a Worcester boiler. My family all have Worcester boilers and have had no issues. Not saying they never break down but they are very reliable and have great availability of spare parts when they're older.
 
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Bobsyeruncle said:
I sell boilers for a living and I have a Worcester boiler. My family all have Worcester boilers and have had no issues. Not saying they never break down but they are very reliable and have great availability of spare parts when they're older.
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You're not the only people I've heard say that. People who sell/install/service boilers seem to prefer Worcester for their own installations.
 
JonathanRyan said:
You're not the only people I've heard say that. People who sell/install/service boilers seem to prefer Worcester for their own installations.
Click to expand...
We do sell various makes.
Worcester, Vaillant, Glowworm, viessmann, ideal etc....
 
We had 2 Worcester combi. "New" one has been in 5 years. Old one did 25 years service. Wouldn't consider another make.
 
Our house had a conventional boiler when we moved in but that died after a year.
Replaced it with a Vaillant combi and hasn't missed a beat in the last 5/6 years.

We do have very high water pressure here and opted for the size up from what was recommended.
 
bass_junkie83 said:
Our house had a conventional boiler when we moved in but that died after a year.
Replaced it with a Vaillant combi and hasn't missed a beat in the last 5/6 years.

We do have very high water pressure here and opted for the size up from what was recommended.
Click to expand...
I should have mentioned, we also have very high pressure. In fact we had to have a restrictor fitted to meet boiler spec.
 
Cockney said:
I should have mentioned, we also have very high pressure. In fact we had to have a restrictor fitted to meet boiler spec.
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We had to replace all our plastic hozelock garden hose fittings with brass as they keep exploding, and still the hose itself periodically swells and blows itself out of the connectors.

First world problems heh! :LOL:
 
bass_junkie83 said:
We had to replace all our plastic hozelock garden hose fittings with brass as they keep exploding, and still the hose itself periodically swells and blows itself out of the connectors.

First world problems heh! :LOL:
Click to expand...
But at least we get a free power shower. :D
 
Our old Thorn Apollo (IIRC!) lasted about 30 years and was replaced with a Potterton Promax SL 10 years ago. The old one needed a new thermocouple every 4-5 years and the new one has needed nothing other than an annual look at. Both are/were conventional types rather than combi.
 
Bobsyeruncle said:
What make/model do you have?
The kitchen sink may be closest to the boiler but may not be the shortest run. It depends on where it's been connected to the hot water pipework when it was installed.
Click to expand...

It's a Promax Combi. People who've been to repair it describe it as "Just a standard boiler."

I can't really see how the kitchen sink would be a longer run than the bathroom as it looks to be about 8ft to the sink... but I suppose anything is possible.
 
Bobsyeruncle said:
Pressurised hot water systems are not suitable for all houses though....
If a decent combi is installed you won't need to replace it after 7 years.
My experience selling boilers is that many combi's last for 15 years +
Conventional boilers are simpler as the pump/valves etc are external to the boiler and are generic, whereas in a combi they're built in and model specific.
Click to expand...
Our pump is built in to the boiler, but it’s not a combi, it’s a WB Greenstar Style. It was in the house when we moved in but is a couple of years old. Have to say it’s excellent in conjunction with a pressurised water system.
 
Craig1912 said:
Our pump is built in to the boiler, but it’s not a combi, it’s a WB Greenstar Style. It was in the house when we moved in but is a couple of years old. Have to say it’s excellent in conjunction with a pressurised water system.
Click to expand...
Yours is a sealed system boiler which is a different variation of a conventional boiler.
 
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