Help!!!! - Combi Boiler lost all pressure

[AndyJay]

Hi all.
Our Baxi 105e combi boiler suddenly lost all pressure!
All hot water is lost and when i try to re-pressurise, the water comes straight out of an overflow (copper pipe from the boiler to outside grid).

There is also a plastic pipe that vents to the same grid outside, but the water comes through the copper one.
I've turned the valves to shut off any attempt to refill the system.
I'm not sure what position they should be in for normal use, but if i try to refill, the water just goes straight out the copper pipe.
God I sound such a layman

Any help or advise would be very helpful.

Thank You
Andy

 

[longdogs]

Sounds like the pressure relief valve letting water through.