Surely that would depend on the appliance, if it’s an older appliance that could be range rated anywhere from 11 to 18kw you would go off the figure it is set as for it’s intended purpose.
Try telling that to the networks / meter people anywhere upto 7m3 on a 6m3 meter they will say it’s fine with diversity
They're about to rent the property so needs a gas safety cert.
Evil: Regardless of the age, and I get what you mean, in that you SET the level, as opposed to a mdern bouler that modulates, all calcs should be done at the maximum possible level. If, on the other hand, you are trying to get an existing situation working then I agree, you would set the boiler to a level that works.
Shaun: The networks seem to get away with making up their own rules, and a lot of their guys do not understand boilers. They do their tests with the HW on, and refuse to acknowledge that the "test" is with the boiler at FULL rate. When I did a stint with NG 3/4 years ago, there was an old BG (from the mid 70's) guy who blamed, specifically, Worcester boilers for the pressure problems because they "sucked" the gas out if the system. I tried to explain how modern boilers worked, but he just was either not capable, or refused, to understand.
But, Shaun, 7m3 propbably would be okay if that was before the diversity factor is applied (if that iswhat you mean?)
Bill: Re the cert, I had missed that. If everything works okay, and eg the hob is not droppong when the boiler is not on full, then one would note the discrepency, and issue the LL. If there was an issue, then you would apply the procedure.
