Central Heating

New house - Central heating only works when hot water on

Anonymous user 23/02/2024 - 2.48 PM

Hi, I have a question. I've searched already and seen various answers but figured I could try to provide more details to narrow down the problem I have. I have moved into a new house, which has what seems to be quite an old central heating system, and the issue is this: Central heating and hot water are both on a timer, but during the 'on' period it feels as though the radiators come on and off, despite not reaching the temperature dictated by the thermostat. If I advance or extend the central heating only, the radiators do not heat up. I have to have BOTH hot water and central heating on for the radiators to work. I have tried the three scenarios below: 1: CH on / HW on = radiators warm up but come on and off during that period 2: CH on / HW off = radiators do not come on 3: CH off / HW on = hot water pours into header tank in attic I had read in other posts here that it could be a faulty three port valve, and a way to test is to try scenario 3 above. Well, as you can see I tried that but ended up with warm water just draining into the header tank - so I'm not sure what that proves with regards to the valve. Given the above, does it still sound like a broken three port valve, or is there another explanation? Any advice is much appreciated - especially if there are any things I can try at this end to isolate the problem. Clearly getting a heating engineer out is the best option, but I was hoping to educate myself a little in advance.