Central Heating Repair in Sussex - Expert Engineers

Common central heating faults, and what they mean

Where a radiator is cold tells you a lot. Cold at the top and warm below means trapped air, and bleeding it usually fixes it. Cold at the bottom means sludge, the black deposit that settles as steel radiators corrode inside. One cold radiator is often a stuck valve. Some rooms warm and others cold usually means the system needs balancing.

The pump moves the water round. If it fails, the boiler fires but the radiators stay cold. Motorised valves send hot water to the heating, the cylinder, or both. When one sticks, you get one and not the other. A thermostatic radiator valve can also stick shut after a summer off, and a gentle tap on the pin often frees it. In a cold snap, a frozen condensate pipe can stop the boiler too, so see our page on frozen pipes in Sussex.

On a sealed system, the gauge on the boiler usually reads about 1 to 1.5 bar when cold. If it keeps falling, water is getting out somewhere. Microbore systems, with thin 8mm or 10mm pipes to each radiator, clog more easily, so the radiators furthest from the boiler go cold first. If the heating is fine but the taps run cold, our no hot water repair page covers that side.

Wet underfloor heating runs at a lower water temperature than radiators, through a manifold with its own pump and mixing valve. It heats slowly, so a cool floor first thing is not always a fault. If one zone stays cold all day, the actuator on the manifold or the room thermostat is the usual suspect. For the boiler, see our boiler repair service across Sussex.