Water meter and combi boiler back pressure

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The "1 litre /minute" had me baffled.......we're talking about a pressure reducing valve yes?...WTF has it got to do with flow rate???..:censored:
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Well if u got hot water coming from cold tap before the boiler somethings plumbed wrong somewhere (pipes crossed?) as that's not physically possible,, where's it dumping its water from prv on the boiler?
Problem solved.

1) The incoming pressure with no flow was about 3.3 bar. However flowing it is ~6 bar.
2) The incoming water main split into two, one pipe going to the rest of the house and the other to the boiler (through PRV), however somewhere under the floor those reconnected before reaching the boiler. So 6 bar mains pressure was on the other side of the PRV but only when the boiler inlet was turned on and the boiler started to fill (i.e. there was some flow).
3) I can only assume the hot water backing up from the boiler was down to a blockage in the heat exchanger caused by the inhibitor and descaler not being circulated until enough water had circulated. This no longer happens.
4) The 'water dumping' was down to a faulty pressure release valve.

Thanks to everyone who tried to help, and for all the sarcasm and 'thats not possible' comments maybe you learnt something, or probably not...
So the OP fitted a pressure reducing valve in the wrong place and Tony is inventing ways of adjusting valves.

Still not 100% sure where 6 bar came from if there is 3.3 at the meter. Perhaps I'll reread the thread when I get back from the musuem.
Please post a diagram especially of the bit of pipe that gains 2.7 barwhen the water is flowing but loses it when static.

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