New House and the Bl**dy NHBC!

[stuart_craigon]

Hey guys, I'm looking for away to heat a 5 bed house with 2 bath's 5 showers and 9 basins. I did think about getting a WB 30kw system boiler and just putting an unvented cylinder in the loft, BUT the NHBC have told me I can't do that because the roof timbers won't support it. On the other hand I COULD just defy them but I've been told that they WILL inspect the house once its finished because the builder is NHBC registered (as are 90% of builders these days) and it can't be registard with an address or something untill it has been inspected by them. If i put the cylinder in the loft and they come to inspect it and find it there they won't sign the house off and i can't live in it! I just don't have space any where else in the house for a cylinder becasue the airing cupbord isn't deep enough its more like a fitted wardrobe with the opeing on the landing!

I did considder spliting the house in two and have "Zones" and haveing a floor standing combi for down stairs and a wall mounted combi for upstairs. (Oh, before i forget, the boilers have to be in the utility room if you havn't gathered that all ready! lol) I don't know how well that will work though. Please help!

Thanks.

 

[stevetheplumber]

can you not add a couple of joists to the roof to tahe the wieght they do this to take a tank of water so would hold a cylinder just as well

 

[dontknowitall]

Can you ask the NHBC for possible options or are they totally unapproachable?

 

[Plouasne]

Were the roof trusses designed for a COLD water storage tank in the roof ??, if so you could argue that an unvented hot water cylinder is about the same thing, especially if the mass (weight) was about the same, as a standard cold water tank

 

[stuart_craigon]

Ha, Thank you guys. Finally I'm getting some practical advice. Much appreciated.

"Plouasne" and "Stevetheplumber", Thank you for that, Makes sense. I did think about that. I'll need to talk to the builder and see what he says but no reason why not. Which unvented cylinder and boiler do you recommend for that kind of output?

 

[stevetheplumber]

i would be looking at a vaillant ecotec plus system boiler and an ariston unvented stainless steel cylinder make sure the water main comming in to your property is sufficent probably 32mm for what you want
i would also consider putting the boiler in the loft with the cylinder as it sounds your short of space
or if garage is big enough i would put both in there

 

[Bernie2]

You can't just put a cylinder in a roof space if the trusses are not designed to take the weight. You have to know the load bearing capability of the trusses used.

Saying that of course many trussed roofs can be made to support the weight of a cylinder if its properly fitted out. Have a look at the Mitek Catalog for trussed roofs it has a section on roof space water tanks.

 

[P4ULT]

viesmann do a boiler and cylinder in one unit it uses stored hot water from the cylinder and also heats water the same as a combi so you use both hence the hot water lasts a while dont know what its called but worth a look imo. could find out if neccessary but you could look on web

 

[stevetheplumber]

thinking laterally if the floor in the airing cupboard can take the wieght ot the cylinder just build for legs into the corners of the cupboard to take the wieght in the loft like a giant stool

could even be done in 1 inch square steel similar to the arco pack frame just taller

 

[stuart_craigon]

Hey guy's, Got in touch with NHBC after reading their literature on the subject and they couldn't have been more helpful. They said:

"Thanks for your query,the person who advised you about the combi boiler was correct in that it would not be adequate for a five bed house, if you are fitting an unvented hot water system in the roof void of the garage there are several issues to take account of as follows,

1/ The roof timbers / trusses must be designed to take the load

2/ There must be access for maintenance

3/ The system should be fully insulated as required

4/ The discharge from the unvented system should go external of the garage and be visible this must comply with the building regulation as set out in G3

Please note that the system can only be fitted by a person who is certified for unvented systems

I hope that's clear"

Sounds fairly clear and simple to me! Got a price from "McDonald Engineers" in Fife Scotland and they only use merchants they don't sell direct but they say that a 300L unvented unit would be 1k with a "white Good's Finnish" which i think is pretty good. The boiler I want is the W.B 30 CDI system which again is roughly 800 to 1k. Seams to be turning out better than i thought it would, i just had to think a little more sensibly about it. I was getting stressed out at the fact i couldn't have a combi and i really wanted on tap hot water all day. I've spoken to a local plumber and he is quite happy install the system and set it up so that i can have hot water on tap all day. My parents house has a direct gravity fed cylinder and its not long before you run out of hot water if 2 or more people have a shower (we have a second electric shower fed from the mains which, admitadly dose make it a little better but not much!) and it takes all afternoon to heat again. As for a bath! ha that's a joke it its self! We had a new bathroom fitted 2 years ago and the tank would happily fill the old bath no problem! Not anymore! They went and got a deeper bath and now it takes 2 full yes 2 FULL tanks of hot water to fill the bloody thing! you need plan to have a flaming bath at 8pm before you get up in the morning, so that there is enough time to half fill the bath and let the cylinder re-fill and re-heat otherwise it gets to late and you have to go to bed! I'm trying to convince my dad to get an electric combi cylinder (again, McDonald Engineers do a great until) but he won't part with the cash and doesn't see that wet central heating will be any better than storage! I hate storage with a Passion! you need to plan when you want heat! Oh okay "dimplex", now i have to be Michael Fish to know when I'm going to want heat! Get a grip! i want heat at the press of a button not 4 hours later when S.H.E (or S.S.E) decide to give me cheep power. Mum came out with a fantastic line when we were talking about it "oh but you just need to open the vent when you get up, you know, keep it closed so that all the heat is kept in when we get the cheep power during the night and then you can use it during the day" Eh, No mum, i want to get up to a warm house and for it be the same temp all day or hotter if i decide. I don't want to be watching the weather like a hock and have to run round the house opening or closing flaps in bloody heaters!
THIS HOUSE IS F**KING FREEZING! Mum "Oh but ware a jumper!" A JUMPER, IN THE HOUSE! eh, naw! Jumpers are for outside! I love it when I'm in the house alone, you notice the difference throughout the house as to where i am,have been or will be! it much warmer or roasting in comparison to the rest of the house! It's even better when the electric bill comes in, time for Stuart to hide or run fairly quickly quite far away! Dad's on the loose with the bill and he's hot on my trail! rofl!

I do apologise folks for that random out burst! lol

I really just wanted to say thanks to everyone who posted, for their advice and help. Better than the advice i got else where!

Thanks.

Stuart

Links:
Hot Water Cylinder - McDonald Engineers
POWERflow - Unvented Mains Pressure Hot Water Cylinder System
http://www.mcdonald-engineers.com/images/literature/POWERflow.pdf
ELECTRAflow -Wet Electric Boiler Heating System and Hot Water Cylinder
http://www.mcdonald-engineers.com/images/literature/ELECTRAflow.pdf

Great company to work with, If you going to use them or need any help or advice, call: Jamie or Sandy on 01592 611123, Tell them i sent you! You could allways write to them at:
McDonald Engineers (UK) Ltd
Flemington Road
Queensway Industrial Estate
Glenrothes
Fife
(Scotland)
KY7 5QF

 

[stevetheplumber]

nice to get feed back on this and i fully understand the jumpers in doors dilema lol
you didnt say where you were going to site the boiler /cylinder loft garage or utility?
one advantage of siting in garage would be a gravity secondary loop to ensure fast delivery of hot water

 

[stuart_craigon]

Sorry yeah, its going in the loft of my new garage. Right next to the utility room above the boiler so the hot water wont have to go very far. I kind of figured that the less it has to travel the hotter it will be but maybe not.

 

[stevetheplumber]

Sorry yeah, its going in the loft of my new garage. Right next to the utility room above the boiler so the hot water wont have to go very far. I kind of figured that the less it has to travel the hotter it will be but maybe not.

sound like its wound up in a good spot then just remember you need some boards and access to it

 

[stuart_craigon]

I'm planning on fully boarding out the garage loft and the house loft. Plaster board the rafters and board the floors put in a strip light or two, extra expense i know but it will be much nicer to use than my parents loft! one strip of board half way up the middle!

Oh btw, how much extra support do you think a full 300L cylinder will need? The house "kit" comes with a water tank stool but i think putting the cylinder on it might mean it wont fit, Do i even need to use the stool or is it more just a case of spreading the weight of the cylinder over as many joists as possible?

see, the thing is that yes the house comes in timber kit form and the builders will just be putting it together, but i want to make one or two changes such as this because i can guarantee they will want to look for space some where else not realising that i need all the storage space and i want to swap glazed doors for unglazed doors, so i can't really just "leave them to it" because god knows what I'd end up with! Just as well they are NHBC registered! lol

Thanks!

 

[stevetheplumber]

i would imagine its just a case of spreading the wieght dont site it in the middle of the span and try to get it above walls if possible

 

[Plouasne]

The firm that makes the timber frame, is the one you really should be consulting for advice

1 Litre water = 1 kilogram, so 300 ltrs = 300 kg plus the cylinder, say 350kg all up mass/weight x 2.2 to get it to lbs, say around 770 lbs
Then if the roof space is going to be boarded out plus the rest of the "junk" that will be thrown up there

 

[Renewable M]

Might seem a daft question. Have you checked the water supply to see if it'll be sufficient for the house. No point putting in a great big unvented (especially an expensive one from mcdonalds) if the flow isnt there.

It'll just mean that if you turn a couple of taps on (or someone flushes the loo) your flow from the outlets will become a trickle.

And that aint good.

 

[stuart_craigon]

Its not a daft question. Its a new supply and as far as i am aware scottish water are quite happy that the supply will be adaquite for the property's needs.

 

[Renewable M]

So that whole thread was just a way to get the advert for mcdonald into the forum? Call me cynical....

 

[stuart_craigon]

No not at all. I wanted to know if i could use a combi. thanks for the advice.