I have just installed a replacement hob which will be checked by a
corgi man.
But I have a problem. I have 20mb at burner jet but this drops
drmatically when I turn another burner on. With the gas lit you can see
the flames reduce in size when more than 1 burner is on at a time. This
happened with our old hob but I put it down to the age of the thing.

I did an extension some years ago and then about 5 years ago moved my
boiler to the garage.This was checked by a corgi man, he actulaly made
the final gas connections. I think the gas hob problem coincided with
boiler move but as I say, i put it down to the age of hob.


Here is a diagram of the pipes (approx including allowance for elbows)

2mtrs @ 22mm 10mtrs @ 22mm
Meter-------------------------TEE----------------------------------------------------------------------BOILER
1.6m3/hr
|
| 12mtrs @ 22mm
14mtrs @ 15mm

|---------------------------------REDUCER--------------------------------HOB
1m3/hr


I used the following link and calculations for pipe sizes all look ok?
Any ideas what the problem may be? I'd like to know whether Corgi man
will need to lay new pipes etc.