Central Heating for 4th Floor Flat

[ski82]

Hi,

Hopefully someone can give me some advice.

I am in a flat on the 4th floor of a building and looking to have a gas boiler and central heating installed. The central heating would comprise of 6 or 7 radiators and the flat is 80 sq m.

The gas meter is located at the front of the bottom of the block, the pipe from there then runs to the back of the building under the communal stairwell. Then up the back of the building and back inside to the flat. The pipe run from my measurement is in the region of 30-35 meters in total (with it being around 24 metres up and around 6 metres across) with about 5 right angle turns and I'm unsure on the number of other connections.

The pipe diameter is 22mm from the meter into the flat and that is accessible, it then goes down to 15mm on the way to the gas hob.

My question is assuming the gas supply from the meter is around the standard, which I understand from reading this forum is around 21 mbar, would a Combi Boiler receive a adequate supply of gas? As I would assume not form what I've seen on this forum but the people I've had round to quote seem to think otherwise.

So far I have had four people provide quotes, 1 recommended a 28w boiler when I raised the gas flow they replied that they have fitted them in similar flats and they work fine. 1 mentioned the gas may be low coming in so I should only go for a 24w boiler that works down to 13mbar. Whilst another again mentioned the gas and said a Ideal boiler would be best as they work well with poor gas flow. The last said from his calculation a 9w boiler is all that could be supplied sufficiently, so a small boiler with a water cistern would be best.

The gas pressure hasn't actually been tested, I'm not sure how they would be able to test it as there does not seem to be a valve that can be seen unless there is someway to do it via the gas hob.

Thanks for any advice you can give.

 

[Agile]

Yes, you have had people who are prepared to install something that does not meet the regulations just in order to get the job!

Only 1 mbar pressure loss on full load is allowed.

You probably only need about 6 kW for heating. But the gas cooker also has to be taken into account.

The pressure loss is measured by the pipework detail you have given.

It may be possible to upgrade the pipe sizes near the meter and just possibly elsewhere as well. So a slight lowering of the pressure loss may be possible.

But most would advise a heat only boiler and a hot water cylinder.

Certainly many boilers will still work with an undersized gas supply but that is not correct!

To me your experience is a sad reflection of the lack of attention to the regulations that many will follow.

Tony

 

[rules&rulers]

As Agile has already said, i wanted a combi boiler in my new flat also 4 floor. (existing heat/hot water being electric).

My installer worked out the discharge rate with existing pipework it failed and another calculation with the only visable pipework being increased to 28mm (2.5m) also failed.

So the combi idea was over but a heat only boiler was the answer.

Its the gas discharge rate m3/h which is important. chart info http://www.installeronline.co.uk/wp-content/uploads/2013/06/Size-matters.pdf

I understand if there is insufficient gas available at the appliance it will be classed as dangerous.


Also not gas related,being a leashold flat the owner of the building had to give written consent and permission for the wall to be drilled and a flue installed,that was another hurdle to clear =time delay and more cost.

 

[Razor900]

As Agile has already said, i wanted a combi boiler in my new flat also 4 floor. (existing heat/hot water being electric).

My installer worked out the discharge rate with existing pipework it failed and another calculation with the only visable pipework being increased to 28mm (2.5m) also failed.

So the combi idea was over but a heat only boiler was the answer.

Its the gas discharge rate m3/h which is important. chart info http://www.installeronline.co.uk/wp-content/uploads/2013/06/Size-matters.pdf

I understand if there is insufficient gas available at the appliance it will be classed as dangerous.


Also not gas related,being a leashold flat the owner of the building had to give written consent and permission for the wall to be drilled and a flue installed,that was another hurdle to clear =time delay and more cost.

Well fork me!!

That was a better answer than most of the pros give over here!!

Top banana

 

[ski82]

Thank you for your replies Agile and creamcrackers.

That's reassured me my understanding after reading around was correct, in that the supply won't be sufficient to meet the required standards though the combo boilers may work they wouldn't be working how they should. I'd guess that might also have implications on any warranty on the boiler, as I would be supplying it with less gas than the minimums the makers specify, though maybe they wouldn't test that.

The person who said the supply isn't sufficient did mention new piping but said that due to it being requiring scaffolding and going through a communal area that would need to be pulled apart to an extent and put back the costs of doing so would be prohibitive.

I had read somewhere creamcrackers, that as you say as the supply of gas is low the system may not be signed of in full and could be noted as not up to current standards or one of the other classifications though I'm not clear on how they work, other than a couple mean it's ok for the time being and one means do not use.

It also sounds like the last person I had round is recommending a system similar to yours, has that worked well for you.

Thank you for the link, that's probably the clearest explanation I've seen (not that I fully understand still). Looking at the table and the fact I would have a hob and (maybe have) a boiler it seems that would mean the installation is split in two and my length of 30m would have to be doubled when working out the discharge (and just projecting in my head further from the table) it'd likely be less than 1.

I have spoke to the owner of the building and they are happy for it to be done for a fee, just need to give them a plan as you say it is more time and cost.

Thanks again for you comments and advice, it left me quite unsure what to do with one person saying one thing and three others say another as to what is best to do.

 

[simond]

If your gas supply runs through a communal shared staircase it can't be copper, there are other rules at play here.

As above, system boiler and cylinder would be the answer. Even a 24Kw combi would have excessive pressure drop.

A gas registered installer cannot install a new appliance with a low working pressure; when a new appliance is installed standards come into play because that is what British Standards are for.

Also the hob is not designed to work safely at 13mB so the advice you have received from some quarters is remarkably shoddy. The installers who gave it will be working next week in someone's house, clutching their Gas Safe card. Buyer beware.

 

[OwainDIYer]

Can you(*) move the meter (and governor) to the back of the building to shorten the length of consumer pipe required?
(Obviously by you* I mean Transco or whatever they're called this week)

 

[Dan Robinson]

Good luck with that

 

[ski82]

The property management company did mention possibly connecting to where there is another set of meters in the building next door as the two buildings are effectively one building, so they could allow me to. No idea of the cost of getting to that area but having looked at the back of the building it looks again like it'd be a lot of work.

Simon, I think the people that have been around mentioned the piping being steel, not sure if it going through the communal area would be up to current standards as the building was converted into flats quite a while ago I think.

Thanks for also saying what creamcrackers and what one person who has been around has said would be best, water cylinder and small boiler.

When we moved in a few weeks ago there was a tag on the pipe from the meter with a warning from British Gas, the gas was on though. At the time, being my first experience house buying, I didn't have an idea of what it meant. So had someone come round recommended by a friend who tested the hob and meter and he said it was fine, he just said it was probably because of the piping in the communal area, though now you say the hob might not have sufficient supply maybe it was that.

 

[simond]

The hob would not have sufficient supply only if some chancer connected a combi to the supply, even one that could work down to 13mB when on full load. My point was that the hob could not safely be connected to the same supply with 13mB working pressure in the house, without significantly upgrading the pipework, whatever the make of combi.

As things stand today, I expect it is OK.

I think you should stop getting quotes and use the person that suggested the boiler/cylinder option. This is a small domestic job and multiple quotes raise prices for all customers because they waste lots of our otherwise productive time. As our time is finite, we all have to pass on the loss of our efficiency to our customers. Think of only getting paid for 4 out of 5 days you work; you'd need to earn more in the 4 days. Well if everyone gets 3 quotes, we're all wasting 2/3 of our time.

When the Government go on about the importance of raising efficiencies of labour..... I wonder how they can be the same people who advise getting 3 -4 quotes on tiny domestic sized jobs.

After all, you are lucky if they obtain 3 quotes on a nuclear submarine or an Olympics security contract. On the massive £33M a year Warmfront contract they just gave most of it to EAGA Group. Even when they f88ked it up they got it renewed every year.