one pipe heating system

Just moving into the ground floor apartment of a 7 storey building. The building has a central one pipe heating system. We needed to move one radiator but the problem is that it no longer heats up. The pipe going in is hot but the one leaving the radiator is cold. The radiator, valves etc are...

Things I’m thinking it might be 1. Historic magnetite blockage at a tee or elbow? How could I find it? Is it likely? (Originally it would have been a vented system with a hot water tank in the airing cupboard but it is pressurised combi now.) 2. One pipe system? Or two pipe...

I've just acquired my parents house with a one pipe heating system. It has all worked fine for over 30 years, but we need to move a radiator in one room, i.e. change some pipework, and I also want to replace the 1960s radiators everywhere with some more modern looking ones. Every boiler...