I think terminology is getting confused here![]()
Boiler is the device that heats the water for a ch system.
Hot Water cylinder is what stores the HW for the hot taps, whether this is provided by immersion heaters fitted to the cylinder, or in fact indirectly by a boiler.
What exactly do you have?
Building control have no interest in pressurised 'system' boiler, which is what I take your original post to mean.
BC are however very interested in the installation of an un-vented mains pressure hot water cylinder, which as said already needs to comply with G3 regulations and be fitted by a suitably qualified installer.
From the vagueness in your posts, I take the inspecting engineers comments to mean that the pressure releif valve discharge pipe, from what ever you have, has been terminated, open ended under the bath.
This would explain his comments that it would need to have a hole drilled through external wall and be terminated according to G3 regs outside.
Yes the HEPV0 trap and internal soil stack is an option, but is also a grey area, as not many, if any, unvented cylinder manufacturers actually approve this method yet.
Seems like a direct unvented water cylinder, which due to its size, >15 litres, is certainly covered by G3 regs.
The chap who has inspected the installation sounds as though he is correct.
This is where you will spend some money and time.
You may be better off getting it regularised and putting it down to experience.
You could easily convert it to a vented cylinder running off the water supply tank you must have had (or been connected to) previously.
No BC reporting or emergency discharge is then required. All you have is an expensive cylinder and possibly a lesson learned, always get a reputable contractor.
So its not a boiler thenThe boiler is an 'Unvented Mains Pressure Water Heater'
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