Gas Boiler Regulations – Landlords Question

I am very pleased now that we opted for the modern industrial look and all our internal boilers have 'feature flues'. Fully visible from boiler to external wall. I'm very glad the flats were let before I got round to boxing them in!

I am raising another point elsewhere about the change in regs reducing the allowable pressure drop between meter and boiler. It now seems to be between 1 and 3mb, leading to a requirement to rip out 22mm pipework installed for the same 24kw boiler [1 bed flats] installed less than 10 years ago and replace with 28mm pipework to deliver 18mbar at the boiler, whereas the manufacturer is happy with 16mbar, which the existing pipework provides. this cost about 1/3 the cost of the new boiler, and my gas engineer says it's happening all over. This is a mad waste of the country's treasure unless there is a good case for it: what is the case. The 2003 regs appear to have been content with 12.5mbar at the boiler!

Chris, I am not sure, but there may be several things you might be able to do if you do not want your pipe size increased from 22 to 28mm,

As you said they are 24kw boilers in one bedroom flats, you probably don't need all 24kw of heating , so get hold of a friendly Gas safe Engineer, and ask him to turn down the burner pressure to yield lower heat output, this will consume less gas as the output of the boiler has been derated, to say 20Kw or may be even lower to like 18Kw, this will exert less demand on gas flow and hence your differential loss will be minimum and give you the minimum required pressure at the boiler which is tested on its full output, of course turning burner pressure down also mean the hot water will be heated to a few degrees less, but this is not a real problem as we always have to mix cold water as is usually ample hot.

Other things you could do is to ask your energy supplier that your incoming pressure at the regulator is not enough, it should be minimum 20mbars, but can be as much as 21 or even 22mbars, so get that meter regulator re-adjusted, as a slight increase in pressure at the meter means you get a minimum required at the boiler. BTW, I am not an RGI, so beware, but have a word with your RGI, most are very helpful and will do these adjustments without compromising safety, it is just many feel incompetent or scared to do things that they either lack knowledge of or have no confidence in their own abilities.

Mike - thanks for the comment - I'll follow it up. I am really trying to check on my RGI's interpretation of the regs - which I haven't found yet. A year or so ago I had a fine turnaround with the previous RGI who wanted me to drill holes in the 600mm thick walls of the old Victorian pile for an air supply for the gas fire, rated at 7kW. getting hold of the regs I found that such piles are deemed to have an air supply. And anyway, using the equation in the regs, it appeared that the air vent required was 0sq mm!

He gave way and works for others now.

that's absolutely amazing Chris! just goes to show you how many gas safe engineers out there are less competent than they should be, many wouldn't take unnecessary risk on to themselves, by deviating appliance ratings, how ever, imagine a bus driver refuses to take a diversion just because he may not be familiar with his new diverted route! and wouldn't want to take unnecessary risk! will all be stuck! and it can be a nightmare for some.

There is a technical jargon for de-rating appliances, it is allowed I am sure, as one of my RGI's told me that my own Vaillant boiler was being driven to its max heat output and that i could prolong its burner's and the heat exchanger's life by de-rating it by reducing the gas pressure at the burner, within the limits, which he did and I have not noticed any significant change in hot water temperature, even when the knob is held half way, and as for CH I normally run mine at very close to lower temperatures like between 35 to 45 degrees depending on how cold it is outside, and I run it more constantly at this lower temp. than at full blast on a timed period!

Further more the pressure at the furthest appliance is measured with 3 of the 4 burners rings running on a gas hob, so again if you come unstuck, get rid of the gas hob and put an electric one, if it is any easier.

I have some quotes from the second edition Plumbing Heating and Gas Installation by R D Treloar, which says Standing pressure at the meter when all appliances are off should be between 20 -25mbars, if not within this range contact your supplier,

The working pressure at the meter with all appliances running to their full max should be 21 mbars +/- 1mbar.

Working pressure of the system, this is maximum pressure drop across the system should not exceed 1 mbar! (pipe sizing comes into this)

As for optimising heat output, you refer to manufacturer's installation & commissioning guide where it tells you how you (meaning RGI) can optimise the heat output by turning the burner pressure down, graphs are shown indicating at what pressure level you get corresponding amount of heat output in kw.

It is worth to be just wise and get ahead of your RGI's trying to give you a load of bull quite often. (RGI's don't like me on Forums!)

im not keen on rgi's either. money for old rope and one was adamant that a new cp12 is required every time a new tenant moves in! greedy b*******.

When I had an issue with my boiler (which wasn't under cover), British came out and fixed it for £100 (fixed fee) despite the fact the flues were inaccessible. They did however stick a big "At Risk" sign on the boiler and said that I had to install hatches imminently (they also said I would not be eligible for Homecare until I did this). They said that fixing the boiler was separate to the issue of the flues and so they were happy to do the job.

I can therefore see why you're unhappy with your plumber. I would say that you should pay the bill but give them a negative review and warn others against using them.

P.S. I am not saying that British Gas are perfect, far from it, but in this instance they came good.

Check any damages or blocks available in the boiler regulations before installation. Chimney flue system should be properly maintained for an effective use.

Hello,Gas boilers problem every where as I think. Example here.I Had over 20/30 year old outside floor mounted boiler for 18 Radiators and hot water tank system since I bought house 5 year ago.
I never had problem and all working O K.Last year I called British gas and ask for service and give me safety certificate.They came and all OK except vent to be extend and fine .so done. Never called Engineer in year.
AS Renual due so I renewed contracts even they put up premium and annual service due so I booked appointment on 26/03/2013 in advance before I go on holiday on 3/04/2013.
Engineer came and checked and Cut off supply and said you need to replace boiler as not safe to use and energy efficient.I said all OK now what!!!!.This is the way...

I called them the manager told me some one can come after ester Tuesday to give estimate .How can they take one week for emergency appointment. So I refused them.And called and cancelled my new contracts.and ask for my D/D payment and they did so.
Lady with 6 children living in house .So I called one of private engineer and he looked and gave me estimate and I bought boiler next day and fixed in total 3 days. all work done and paid and gone on holiday and just back today.

British gas lost contracts and business too.Be Aware of British gas too !!!!

I know this is expensive business but we have to stay with rules and regulations.

The engineers are very very nice polite and any I can re-command to any one in M25

area. Please contact me via email.Thanks.

It's six of one half a dozen of the other. Yes of course the plumber should have asked if you had the inspection panels. But at the same time, as a landlord you should know that you need to have these panels.
I don't agree about the fee though, personally I would have worked something out and not charged as much.