Do the presssure rising test I mentioned, and now you have found the boiler PRV discharge outlet connect a balloon or freezer bag or something over it and see if it catches any water over a 24 hour period, the gas indicator you refer to is the last straw, might or might not work and is expensiveThanks, having an issue/problem on both systems probably hasn't helped me. Vessel replacement and new PRV on the unvented cylinder and a leak on the main system
I just checked and there is a pipe from the boiler to outside of house which isn't leaking so i guess it is as I originally thought with a leak on the pipework somewhere. What is the next step here, professional company to gas it?
Thanks