Hi All, So I decided to switch from a system to combi boiler, a 35kw unit rated for 16ltr/m. Stopcock has a non return and pressure limiting valve, currently 3.0 bar static. It's just me in the property so I was looking forward to the mains pressure shower. I'm getting just over 6ltr/m from the upstairs bathroom hot tap with no other draw on the system. Really not sure what to expect from a combi but this doesn't seem normal. There are other problems with the install, either trapped air or a dead leg so combi fires on cold water briefly (obviously it doesn't heat the cold water). But this indicates a pressure issue. Have spoken to installer, his response is to fit a non return valve on the cold feed to the boiler but I'd rather get the underlying issue resolved. I look forward to hearing your thoughts, help needed!