Radiators Cold at the Bottom? Sludge, Power Flushing and Cardiff Hard Water

Cold at the top usually means air. Cold at the bottom means sludge — and sludge is what quietly wrecks pumps, valves and heat exchangers.

What sludge actually is Iron oxide. Steel radiators corrode from the inside, and the black magnetite it produces settles in the bottom of every radiator and collects in the boiler's heat exchanger. Add limescale from Cardiff's moderately hard water and circulation drops off.

Signs your system needs flushing - Radiators cold at the bottom or in one corner - Some rooms never get warm while others cook - Noisy boiler, kettling or banging pipes - Dirty black water when you bleed a radiator - Pump running hot or failing repeatedly

Power flush vs chemical flush A chemical flush circulates cleaner through the existing system and is fine for light contamination. A power flush uses a high-flow, low-pressure pump with a magnetic filter to physically drag debris out radiator by radiator. Heavily sludged systems need the power flush.

Fit a magnetic filter afterwards A magnetic system filter catches magnetite before it reaches your boiler. Most manufacturers now require one for the full warranty, and it's the cheapest protection you can buy for a new boiler.

PHBLUE power flushes central heating systems across Cardiff and fits filters as standard on new boiler installs. Call 07545 125168.