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Radiator faults and what they mean
Cold at the top is air, and bleeding it releases the air and fixes it, though if it needs bleeding every week, air is getting in somewhere. Cold at the bottom is sludge and needs flushing. Cold everywhere while others are hot is usually a stuck valve, a thermostatic valve pin that has seized in the closed position, or a system that has never been balanced so that radiator gets no flow. Hot when the heating is off is a valve passing or a wiring fault on a zone valve. Leaking at the valve is a gland nut or a compression joint. Leaking along the bottom seam is corrosion from the inside and means the radiator is finished. Rattling or ticking is expansion noise from a pipe clipped too tightly or a radiator touching its bracket.













