Unvented cylinder and boiler cupboard

[bobbidill]

Hi All, Happy New Year and thanks for reading. Our builder has suggested that by increasing the depth of the foundation in 1 of the kitchen cupboards, we'll be able to fit an unvented cylinder in there.
66sq. m. of the entire 130sq. m will be heated with wet ufh via a 6 outlet manifold. All other rooms will have rads, 6 in total.
The overall Kw requirement of the house is 9.19Kw, although it’s been suggested here that it may be greater.
The pressure and flow are 4.6bar and 24l/min; with dynamic, albeit with some leakage affecting the accuracy, being 10.9l/min and 2.5bar.
The mains water inlet pipe is now 25mm and all the pipework inside the house will be new.
3 questions for those in the know:

1. The Joule Short 250l indirect unvented cylinder, which is 1400mm high and 600mm diameter is what we’re looking at using as the height works. Is this a good option?
2. The cupboard is 2780mm high and 700mm deep. What’s the minimum cupboard width we could get away with to hold the cylinder and all it's pipework and boiler?
3. We’d like to use an Intergas boiler, based on the reviews of them here. What size would you recommend for our setup and are there other brands we should consider?

 

[muggles]

1. Yes, good make, can't comment on size as you've said nothing about expected hot water demand. Your flow/pressure figures seem odd... were there measurements taken before the main was upgraded?

2. Are you expecting to put the boiler above the cylinder? Can you make it any deeper? With good pipework planning, you could get away with 700mm wide if it was 800 deep, but at 700 deep you'll probably need 900 of width. This assumes you're not also expecting to put your UFH manifold in there of course...

3. Excellent choice. Based on your description above, I'd suggest the Xclusive 24, although an alternative would be to go for the Xclusive 36 and a smaller, High Gain, cylinder

 

[bobbidill]

1. Yes, good make, can't comment on size as you've said nothing about expected hot water demand. Your flow/pressure figures seem odd... were there measurements taken before the main was upgraded?

2. Are you expecting to put the boiler above the cylinder? Can you make it any deeper? With good pipework planning, you could get away with 700mm wide if it was 800 deep, but at 700 deep you'll probably need 900 of width. This assumes you're not also expecting to put your UFH manifold in there of course...

3. Excellent choice. Based on your description above, I'd suggest the Xclusive 24, although an alternative would be to go for the Xclusive 36 and a smaller, High Gain, cylinder

Thanks Muggles. The measurements were taken after the main was upgraded. I suspect that there was an issue, ironically, with the dynamic flow rate being so high that we couldn't measure it accurately and that the pressure gauge fitting leaked a bit, meaning that the measurements themselves were disproportionately low.
We do want to put the boiler above the cylinder and might be able to stretch to make the cupboard 800mm deep, I'll investigate. The UFH manifold is situated elsewhere.
Would it be best to go for the a higher Kw Xclusive, given that some have suggested that we may have underestimated the heating Kw requirements?
As you and Dan seem, from what I've read, to know an awful lot about this sort of Intergas boiler based system, would you recommend anyone in particular who could install in the London area?

 

[bobbidill]

Wouldn't we need a system boiler and not a combi, which the Xclusive is, for this system though?

 

[muggles]

I think you should at least re-check your heating requirements. Search online for a whole house heat loss calculator.

The Xclusive can be used as either a combi or a system boiler. Its main advantage over the ECO RF is that it has a greater modulation range so it'll be more efficient in your low heat loss home.

London is quite a big area. Someone in the North won't cover the South. Can you be more specific?

 

[bobbidill]

I think you should at least re-check your heating requirements. Search online for a whole house heat loss calculator.

The Xclusive can be used as either a combi or a system boiler. Its main advantage over the ECO RF is that it has a greater modulation range so it'll be more efficient in your low heat loss home.

London is quite a big area. Someone in the North won't cover the South. Can you be more specific?

I've rechecked the heating requirements using 2 calculators, 1 of which gave a result of 12.9Kw, the other which had more accurate information entered was 10.7Kw. I don't have enough knowledge to know how to incorporate these results into the calculation to determine which boiler we need. Thanks for explaining the benefit of the Xclusive. Do these calculations establish whether this would still be appropriate please? We're in East London. Thanks again.

 

[bobbidill]

I forgot to add that the expected hot water demand will be 2 10 minute or so showers in the morning, 1 bath in the evening, 1 baby bath in the evening, dishwasher likely to run once per day and washing machine will probably run once per day as lots of sports wear to wash.

 

[bobbidill]

Muggles, I looked on the Intergas website today at installers, but a personal recommendation would be preferable. I'm hoping some of the other knowledgeable boiler and unvented cylinder members let me know their thoughts too. Thanks again.