Dazza

Thanks again guys. Yes, I def need to draw out a plan for runs! So it is definite that I need a system boiler with hot water cylinder - think someone suggested a 400 litre unvented or thereabouts (as well as kitchen etc will have 4 ensuite bedrrooms with showers)? Sorry if this sounds like a silly question, but how do you maintain pressure if all 4 showers were running at the same time? Also, the location where water tank would go is a bit limited in head height so I cannot have a "tall" tank - does anyone have any recommendations for tanks to suit (preferably pre plumbed to make life easier for me!). Also, is there a general consensus of a good brand boiler to go for or is that one of those where everyone has a different opinion? I did get a recommendation form an online boiler supplier for a Viessman boiler - any thoughts?

Thanks again guys, you have been most helpful!

Well, I would be foolish to ignore everyones advise, so I will stay away from multifoil! Actually the celotex with plastboard over was not that much more expensive and is tried and proven. Of course if I could get insulated plasterboard at a good price, then that of course is the easiest option.

Thanks for the reply - I take it you have experience with the multifoil? Surely it must work or wouldnt pass building control?? Looking at Kingspan they specified fitting the insulation on 25mm battens too rather than direct bonding to wall, so it seemed to me that was the best option and also gave a service void which is very useful. Excuse my ignorance, but who is CCF?

Yes LPG is more expensive but cleaner and can be hidden away - we went with LPG with our eyes open because it suited our needs better. I think it is also getting more competitive - we are with flogas and is £0.40 per litre + VAT and contract was only 2 years - we also took out the contract about 1 year ago and only just got around to installing the tank and getting filled, so will last us until we are out of contract anyway!

Thanks for all the replies!! It has been really useful and productive to get others input! So, I have had a real rough look at approx energy loss and cost of internal insulation does definitely seem worthwhile! Just in case anyone is interested I approached it like this - the U value for my solid brick walls is probably somewhere around 2 W/m2.K - I have assumed this for the roof too as that is uninsulated. In my area I have figured the average annual temp is around 10C, so with an internal temp of 20C, give my walls a loss of 20W/m2= 175kWh/pa. Ignoring doors and windows, I have roughly calculated total area of external walls and roof is 655m2 So assuming gas is around 7p/kWh, annual cost would be £8146 for heat loss. If I insulated to U value of 0.3 this would come down to around 3W/m2.K loss per m2 = 26.28kWh/pa = approx £1205 pa cost for heat loss. So insulating to achieve 0.3 could reduce annual cost by around £6900!! On rough costings, I figured to insulate 655m2 using Kingspan K18 it would cost £14410, using 50mm Celotex and plasterboard over would cost £7,618, or using multifoil it would cost approx £6340. So it seems to me a pretty convincing argument that the insulation will pay for itself pretty quickly! Which brings me to my next question - the multifoil looks like the cheapest option and it is lot easier to work with than PIR boards, so was thinking of going down that route. Does anyone have any experience using multifoil for internal wall insulation?? As we have decided that internal insulation is the way to go (it will actually help with the refurb as well for ease of wiring etc) then once insulated, I think the boiler demands will not be anywhere as large so can get away with a single boiler.

LOL! Actually I exaggerated - the flow and return pipes from the boiler are around 60-70mm OD, but when covered in lagging look much bigger!

Thanks for all the replies and advice guys. We are definitely going with the LPG (obviously as it is installed!), but I guess now it is a matter of what size boiler we require etc. The property is old and has triple brick walls (so over 300mm thick) but does have double glazing - there is also no insulation between floors. As has been suggested, it does seem like a good idea to get an idea of the heat losses from the property, so Im going to go away and work on that. Can anyone suggest a good place to find U values for the various elements - external walls/internal walls floor etc?

For a variety of reasons we wanted to move away from oil, hence we went to LPG. We did the numbers on it and actually it worked out pretty close as a cost comparison - but we also got the in ground tank tank supplied and fitted FOC!

Thanks for the spreadsheet - I will give it a go and then we can see where we are. I was reticent to insulate the house as it is quite large and to insulate all the walls floors/ceiling will cause a lot of disruption and cos, but I will have a go at the spreadsheet and see what I find.

I can get the tank vertically within about 2m, but horizontally it would be about 10m. Reason for removing the pipe work is that want to use the area where it is currently as a habitable space and the pipe work goes everywhere in the basement making it pretty unusable at the moment. There some even bigger pipework - some of the pipe work is about 4"!! So I guess for the heating, I would need to get all the bigger stuff out and bring it down to 15mm which might be achievable?

Havent done heat loss calcs but will give it a go - yes it heats the 150L HW cylinder easily!

Thanks for the reply. The current hot water tank is a vented 150l tank just behind and to the right of the boiler - although it leaks a bit and needs replacing. The current boiler is in a cellar, but the replacement cannot be in a cellar as it is gas, so new gas boiler will be on ground floor. I was hoping to get away with a combi because it makes installation so much simpler, but it seems that is not likely. If I have to have a HW tank it does add a lot more complexity as I was hoping to be able to effectively bypass all the current installation and allow me time to rip it all out, but if I had to add a new HW cylinder with new boiler I would probably need to instal it temporarily and then move it later - but if thats what I need to do, then so be it. Thanks for the advice on the maglclean thing - never heard of them - will look into it! At least that will save me some hassle up front and allow me the time to gradually replace the pipework as I work through the place!

Looks worse than it is - you are thinking asbestos? It is actually yellow rockwool insulation type stuff.

Current boiler is oversize for a domestic installation Im sure - I think it would heat a large industrial building!! Think it is 105-140kw according to rating plate (Harrier GTE 5)

Hi looking for some advice on a replacement boiler. Bit of background - we have a big old farmhouse that I am slowly refurbishing. Current boiler is an oil fired boiler situated in our basement it is massive and drinks oil -see pic! looks to me more like a hospital basement than a house basement! So obviously want to replace and have decided we need to do this sooner rather than later. We have decided to go down the gas route rather than oil and have had a new in ground gas cylinder installed - we have also had a new 32mm water mains installed. so thinking about the upgrade, there are some things I need to look at: 1. Boiler has to service the home for heating & HW (rads and place not super insulated!) - Kitchen/utility/4 beds with ensuites (showers only)/sitting room/downstairs cloakroom - around 200m2 overall over 3 floors. 2. There is a myriad of existing pipework for rads - some of it galvanised. Here is where I need help! 1. Ideally, I would like a combi boiler to be man enough to supply all heating and HW, which I am sure is easily doable, but my question is, do I need a HW storage tank as if all 4 showers running at once think will run out of flow? Any good advise on what sort of system I should be looking at would be greatly appreciated. Also just to add, for HW, there will be some longish runs from gnd floor to 2nd floor if that makes any difference. 2. I want to get this connected up and running as soon as possible as I dont want to buy any more oil for the existing guzzler!! I know ideally I should replace all pipework to new and I will over time, but that is going to take a lot of work. I was hoping to be able to T into the existing HW and CH pipes and disconnect at the existing boiler. My concern with this is there will for sure be a lot of sludge in the CH pipes form the galv pipe and I dont want to damage a shiny new boiler by connecting up to these pipes. What is the advise here please - will it be OK? Should I get a power flush first? Or should I not do this at all - period? I am hoping to be able to do this some way as ripping all the existing pipework out will be a nightmare (there are so many pipes and I think some have been replaced over time and old ones left in situ - so my preference is to tackle it one room at a time as I am renovating the property). Hopefully I will get some good advise as I am scratching my head a bit - not to mntion suffering from paying so much out for oil for the old beast of a boilerl!!

Thanks for the advice Peter W. Rather than take Stihl saw to the concrete sub base, surely there must be someway to run the pipes through the insulation - insulation is a lot quicker and easier to cut than concrete!

Hi Guys, Looking for some advice re the above. As part of a conversion of an old farmhouse to 2 properties, we have built an extension that will have a kitchen diner. Originally when we built the extension, we didn't plan on the island unit, but of course plans change! As a result, I cannot get the 110mm foul waste into the building near the island for drainage as I dont have a lintel in the wall build up to pass through. So, my question is how to I manage to get a connection to foul waste that will meet with building control approval? I have attached a sectional drawing of the build up, and my thoughts were to channel out the insulation and place a 50mm waste into the insulation with a slight fall - I can core this through to the outside, but because it comes out at virtually ground level, I cannot really use a gully for the waste. Can anyone please advise the best way to connect up to the foul waste please? Whilst I am at it, might as well check re the hold and cold water and electrical feed too! My plans for the hot and cold feed are to make channels around the middle of insulation and lay in the plastic water pipes. A similar thing for the electric feed which I will put in plastic conduit - I was thinking of having one of those instantaneous hot water taps too, so thinking to run 2.5m twin and earth? I look forward to some helpful replies!

Hi, just a little bit about me and my project/s! We have purchased a rather larger farmhouse with the plan to subdivide the property into 2 dwellings. We have managed to get planning which is great, and I am now embarking on the long process of undertaking the conversion! So I am sure I will be seeking lots of advice from time to time. I actually do have a question right now regarding a Kitchen Island unit, but I will post that in the plumbing forum as I think it sites best there!!