So many different opinions

[Richhen]

Yes but with the storage combi I understand I get the best of a system boiler and combi boiler together due to the inbuilt cylinder. Therefore whilst my flow will be at 15-16l/min I’ll have much more hot water and will be able to service several outlets, whereas a standard combi would struggle in a large house. Prices are probably coming in at about £500-600 difference for standard combi install vs storage combi install, so thinking its worth the extra investment to get something more suitable for larger house.
Is my thinking correct here?

 

[Mr.B]

The Intergas boiler is a good unit you just have to bear in mind they only have around a dozen direct labour engineers in the UK and they are in the process of making some of them redundant....

That's not what I wanted to hear. It's useful to know, and it helps to get things in perpective when choosing a boiler ... but it's not an encouragement given that, in my area, approved installers appearing on the Intergas "Find an Installer" page aren't all that plentiful.

Al least with Baxi, Worcester or Vaillant you kind of hope that there would be someone familar with their products and that parts will be readily available and those two factors give you some sort of reassurance in the event you have problems - but with Intergas you, again, believe the product to be a good one but you, maybe, have a fear in the back of your mind that the absence of spares on the shelf and dirth of engineers familiar with the products might not be working in your favour.

 

[bernardgreen]

Yes but with the storage combi I understand I get the best of a system boiler and combi boiler together due to the inbuilt cylinder.

How much hot water can the inbuilt cylinder hold ?

How long before that quantity of pre-heated hot water has been used up and the hot water flow and temperature reverts to being dependent on the combi's ability to produce instant hot water,

 

[oldbutnotdead]

What @bernardgreen said.
If you have a large house and poor to moderate mains flow/pressure then your best bet may be to keep a traditional hot water cylinder (with tank etc in the loft) and use pumps to boost your shower pressure if needed. Many modern innovations are about saving space (combi) and reducing the skill level and time required for much of the installation (plastic pipe, system boilers). If you have the space for tankage then keep them, you'll be laughing (unlike your combi neighbours) if your local water board reduce the mains pressure to legal minimum to improve their leak loss numbers.
The boiler sketch- Intergas boilers are mechanically very simple devices with not a lot of moving parts. Maybe WB need all those direct engineers because they've sold a lot of complex boilers with 10 year warranties and it was cheaper for them to have a large repair fleet to deal with the failures than to pay for customers to use their own engineer? Maybe its the Rolls Royce vs Ford car argument- the engineering in the Rolls will be superb but which of the 2 is most cost-effective for driving to the shops and back every day?
EDIT No I don't work for Intergas.

 

[Richhen]

Yes but with the storage combi I understand I get the best of a system boiler and combi boiler together due to the inbuilt cylinder.

How much hot water can the inbuilt cylinder hold ?

How long before that quantity of pre-heated hot water has been used up and the hot water flow and temperature reverts to being dependent on the combi's ability to produce instant hot water,

I’m not to much into the technical details but I understand that a small unbuild cylinder is equivalent to a much larger separate hot water cylinder. I believe the inherent heat in the inbuilt cylinder heats water as well as being mixed with the incoming supply, so a smaller inbuilt cylinder goes further that you would think. When it does run out I understand it fills super quick <10mins, so real world issue of it being empty is minimal.
At least this is how I understand how these things work, but happy to hand over to experts to confirm....

 

[whall3y]

Hi,
So I have a 33 year old gravity fed system powered by a floorstanding ideal Mexico. 4 bed detached, 14 radiators. Good enough mains pressure.

Decided to upgrade.

4. swapping for a standard combi, Worcester 8000 style, £3950

I went through the same process a few weeks ago, similar sized house and rads, and ended up with similar outcome to option 4. Got a few rough quotes and then got my local Worcester accredited installer round to survey, he tested the water flow which was great and allowed me to pick any of the options - I opted for the 40KW boiler to get a good strong shower In total, to replace boiler with a WB 8000 40KW Life (it's in the garage so looks don't too much matter to me), flush, remove storage tank, feed/header, etc, pipework, Nest smart thermostat, Intelligent filling loop, and swap all the TRVs whilst the system was drained (some had been sticking) was £3600. I'm really pleased with it - could probably have shopped around to get price down a bit more, but seemed reasonable.

 

[bernardgreen]

I believe the inherent heat in the inbuilt cylinder heats water as well as being mixed with the incoming supply, so a smaller inbuilt cylinder goes further that you would think.

I do not know how many litres the in built hot water tank is. Maybe as large as 50 litres,

The question is would 50 litres stored at 60°C would give you 50 litres at 60°C ?

Probably not because when 10 litres at 60°C has been drawn off those 10 litres of water will be replaced in the tank by 10 litres of cold water.

The next ten litres will not be at 60°C as the cold water will have reduced the temperature of the remaining 40 litres of hot water in the tank.

The exact effect depends on how the cold water enters the tank.

Does it remain at the bottom of the tank with limited mixing with the hot water or does it enter the tanks in a way that causes hot and cold to mix.

 

[oldbutnotdead]

I’m not to much into the technical details but I understand that a small unbuild cylinder is equivalent to a much larger separate hot water cylinder. I believe the inherent heat in the inbuilt cylinder heats water as well as being mixed with the incoming supply, so a smaller inbuilt cylinder goes further that you would think. When it does run out I understand it fills super quick <10mins, so real world issue of it being empty is minimal.
At least this is how I understand how these things work, but happy to hand over to experts to confirm....

Thats a very interesting concept- where did it come from?
It is possible that the built-in cylinder is maintained at a high temperature and is delivered via a blending valve within the boiler (so if demand in litres/min exceeds the capacity of the combi the stored high temperature water can be trickled in to maintain the output temperature. More complexity, more energy costs (the energy loss per hour from a 90 degree cylinder will be greater than the energy loss from a 60 degree cylinder given the same thickness of insulation). True a small cylinder will lose less energy per hour than a large cylinder (less surface area) but the larger cylinder will retain more energy for longer (better surface area/volume ratio). Sounds suspiciously like a manufacturer's puff sheet extolling the virtues of their (expensive complex high tech) solution- heating water is basic physics, the energy comes from somewhere & if that somewhere is the gas main you'll be paying for it.
Another bonus of the 'trad' cylinder (if you have space for it) is as an energy sink for any surplus PV electricity...

 

[muggles]

That's not what I wanted to hear. It's useful to know, and it helps to get things in perpective when choosing a boiler ... but it's not an encouragement given that, in my area, approved installers appearing on the Intergas "Find an Installer" page aren't all that plentiful.

Intergas have recently changed their rules and to appear on the "find an installer" page 75% of an installer's annual installations must be Intergas boilers. This ensures that only those installers who are very familiar with the boiler are recommended on the website. It's not something to be concerned about - those installers you can see will know their stuff

 

[Mr.B]

^^^ That's interesting to know. In my ignorance I'd have thought that takes some doing, especially as it's still a name that is less familiar than the obvious ones.

Would that apply to the existing installer's names on the site, or just new applicants?

 

[muggles]

^^^ That's interesting to know. In my ignorance I'd have thought that takes some doing, especially as it's still a name that is less familiar than the obvious ones.

Would that apply to the existing installer's names on the site, or just new applicants?

It applies to all installers - everyone was kicked off and now only MiTECH registered installers are there - those who have 75% Intergas installs

 

[Mr.B]

That's quite something isn't it?

I confess it was Razor's mention of Intergas making some of their own maintenance men redundant that troubled me. I know Intergas gained new owners and at the time it was announced I was fearful of "a new broom sweeps clean" happening and rightly or wrongly I put two and two together.