A bit of an aside, but looking at the Ferroli 38 manual, it says gas pressure at the boiler must be 20 mbar MINIMUM. The "nominal" supply pressure is 20 mbar, but the regs say it can be 21+/-2 mbar after the meter. So with 1 mbar loss between meter and boiler it can be 18 mbar at the boiler and meet the regs. My guess is Ferroli just quote the nominal figure and haven't bothered to put any thought into it, but they might be trying to give themselves a get-out in the event of a problem. In practice I'm sure the boiler could cope with a lower pressure. I remember seeing data for one boiler which gave an actual minimum acceptable pressure.Have the regulations changed? I dont understand how I have not had any pressure issues with my current boiler, but now i must go smaller.
being gas safe registered means they have paid protection money to the same company who collects the TV licence (Capita) so as to say they don't need anyone checking their quality of work. It is not, nor can it ever be, a measure of competence to undertake BASIC maths calculations. You can have the pipework checked by an engineer (a real engineer) who uses maths but what you want to know is can you use the boiler on the gas supply you have.
So, turn everything on FULL...gas fire, cooker and of course the boiler on HOT WATER mode.
Did the boiler stop?
Did the gas cooker go out?
Did the fire go out?
Did any of the devices falter in any way i.e reduced output/water temp etc.
If they did, then your current supply cannot cope with your maximum peak demand..
So you now want to know what it can handle
So boiler on Hot water..
then gas fire....everything still OK?
Then cooker rings...etc etc,
The problem is that "it works OK" isn't the same as "it complies with the regulations". Regs aren't there to be cherry-pickedIf everything works OK now I don't see why there'd be a problem replacing the boiler with one of similar output. If you want to go bigger it might be worth doing some pressure tests to see if there's anything in hand. Get a length of clear plastic tube to use as a manometer, and measure pressure at the boiler inlet. Also just after the meter, to give some background data. When everything's turned on, and with various combinations if thought necessary.
We understand it's working OK now, but OP doesn't know whether it meets the regs or not. If he does some pressure tests he can find out. If it turns out it's say 22 mbar after the meter, and 20 mbar at the boiler inlet (so failing the 1 mbar pressure drop requirement) I doubt if he'd want to switch everything off and get a new, smaller boiler installed, or upsize the gas pipe. But at least he'd know where he stands.The problem is that "it works OK" isn't the same as "it complies with the regulations". Regs aren't there to be cherry-picked
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