Why Are My Radiators Cold at the Bottom? (And When to Worry)
Cold-at-the-bottom radiators almost always mean sludge. Here's how to know if a power flush will fix it.
If your radiator is hot at the top and cold at the bottom, sludge is a common culprit.
Sludge is iron oxide — tiny particles of rust shed by old steel radiators. It settles at the lowest point of your system, blocking flow.
What to do: don't remove or drain the radiator yourself — disconnecting pipework risks a flood. Note which radiators are cold at the bottom and ask a heating engineer to check the system.
The fix: a full power flush. We use MagnaCleanse equipment to strip every radiator and the boiler in a single day. From £450 for a typical house.
Long-term protection: dose the system with corrosion inhibitor and fit a magnetic filter (MagnaClean). Both standard on every flush we do.
