Secret sludge build-up: If the radiator is cold at the bottom and warm at the top, this indicates a build-up of sludge or debris blocking the hot water flow. System pressure issues: Low boiler ...

If the radiator is cold at the bottom and warm at the top, a build-up of sludge or debris could be blocking the hot water flow. Over time, rust, limescale, and debris collect at the bottom of ...

Why is my radiator cold at the bottom? A radiator that’s warm at the top but cold at the bottom is often a sign of hidden sludge build-up. Over time, rust, limescale, and debris collect at the ...