# Gas boiler pipe size - old 15mm, new 22mm!...

3 fires?!!

if you had 1 fire 1 cooker and 1 boiler, you need to calculate each section separately.

Eg meter to boiler is furthest away and has most number of sections between meter and boiler, for eg 3. You work out length from tee to boiler (that own individual section, ie section b-c) and include all fittings, etc. Eg 1 metre plus 2 fittings, = 2M X 3 sections (max number) = 6M gas rate of boiler, eg 2.5m3/hr - from chart find next size up, prob 22mm would be easily suitable.

If the installation was THAT large, then it would be calssed as commercial probably anyway, total IV over 0.035m3.

Fitting the hanging bracket, fitting the flue and certainly fitting any gas pipes all have to be done by an RGI !

Although I agree a gas appliance is best fitted by an RGI, fitting the bracket (2 bolts/screws) and a push fit flue with at worst two 3.2mm retaining screws, is somthing a monkey can do and certainly that a monkey could check upon inspecting the installation

3 fires?!!

if you had 1 fire 1 cooker and 1 boiler, you need to calculate each section separately.

Last job had 3 fires, over, grill and hob, and boiler 30 Kw (mixed 2 jobs up, the other one was 37) at 15 metres from meter; What would your calculation be for the first section; 4 metres + 4 elbows, gasrate 3.3 m3?

If the installation was THAT large, then it would be calssed as commercial probably anyway, total IV over 0.035m3.

Guaranteed it was not industrial in any way; not in power, not in volume; granted, close, but not quite.

And it's unlikely to fall off, unless it's an Alpha 50

bengasman - depends on the total no. of sections (max amount). it would be 4 metres plus 4 elbows @ 0.5 metres each = 6 metres. X max no. of sections - then from chart, find next size up.

That's what I said, 5 sections. If I understand your theory correctly, you would have to multiply the finding of each section by 5, hence my question: what sort of size do you get to?
I have heard it quoted before, plus a few variations. They work reasonably well with 2 or 3 appliances that are not too different in size, and fairly evenly spaced due to the law of averages. When capacities are quite different and the spacing uneven, the calculation done this way comes out with sizes that are far too big, and easily go over the 35 mm mark.

ok sorry, so with 6 metres X 5 = 30 metres, gas rate of all appliances in total (as is 1st section and supplying them all) but if a gas rate of just 3.3 m3 in total as you stated: it would be 28mm (next size up)

Although I agree a gas appliance is best fitted by an RGI, fitting the bracket (2 bolts/screws) and a push fit flue with at worst two 3.2mm retaining screws, is somthing a monkey can do and certainly that a monkey could check upon inspecting the installation

dave, i recommend you go and work with a manufacturers engineer for a week, you will soon see that a large portion of installers haven't yet evolved into monkies as yet

Although I agree a gas appliance is best fitted by an RGI, fitting the bracket (2 bolts/screws) and a push fit flue with at worst two 3.2mm retaining screws, is somthing a monkey can do and certainly that a monkey could check upon inspecting the installation

dave, i recommend you go and work with a manufacturers engineer for a week, you will soon see that a large portion of installers haven't yet evolved into monkies as yet

With the exception of Vaillant.

Although I agree a gas appliance is best fitted by an RGI, fitting the bracket (2 bolts/screws) and a push fit flue with at worst two 3.2mm retaining screws, is somthing a monkey can do and certainly that a monkey could check upon inspecting the installation

dave, i recommend you go and work with a manufacturers engineer for a week, you will soon see that a large portion of installers haven't yet evolved into monkies as yet

With the exception of Vaillant.

I'm pretty confident he wouldn't be welcome anyway.

Fitting the hanging bracket, fitting the flue and certainly fitting any gas pipes all have to be done by an RGI !

Although I agree a gas appliance is best fitted by an RGI, fitting the bracket (2 bolts/screws) and a push fit flue with at worst two 3.2mm retaining screws, is somthing a monkey can do and certainly that a monkey could check upon inspecting the installation

you would think but how many boilers have you seen installed with th ecore at the wrong gradiant,clearances and poor flue connections or damaged washers?

i thought they were chimneys now anyway

Most new boiler installlations that I see have several installer faults and mostly with the flue.

Whilst monkeys dont read installation instructions, I would expect they could at least fit the flue at the right angle. ( Vaillant monkeys excepted! )

Dave, its well established what an RGI had to do under CORGI and as one of them said to me the GS are the same people so nothing has changed.

Tony

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