Vaillant Boiler is rated at 37kW and Cooker (4 burners plus oven) totals 30kW
EDIT: the calcs are wrong, had the app set to 25 feet, not meters.... pipe is too small.... Good catch Shaun.
It looks like you’re probably not much over, dependant on how many fittings have been used.
Roughly, 67kw at 25m and 14 high loss fittings comes out at 1mb drop in 28mm pipe.
Is there a gas test point under the boiler or did they test at the gas valve inside the boiler? If they tested at gas valve, it will add anywhere from 1mb-2mb on the reading.
If a reading from a test point under the boiler was 2.5mb, I’d agree but at the gas valve, I’d want to install a test point.
As above, I’d get someone else in who can pipe size and get a test point installed under the boiler.
Also, either way, because I think you’re pretty close to 1mb (depending of number of fittings), is there any exposed gas pipe? Or can you get to any relatively easily (under floor boards etc)? If so, a section could be ungraded to 35mm.
The whole pipe doesn’t need to be 35mm. It doesn’t even need to be the beginning section. Gas doesn’t care where the section is.
You also need to be careful not to upgrade the whole pipe (more than is needed) or the total volume will make it commercial. This is likely the reason the engineer told you to move the meter closer. I guess they don’t have a commercial ticket and don’t want to lose the business. Or they struggle with pipe sizing.
Out of interest, where in London are you?