02/09/2026
Turn the heating on for 10 minutes today. What you feel tells you a lot.
Cold on top, warm at the bottom means there's air trapped in the system. Warm on top, cold at the bottom usually means something has settled at the base of the radiator. One radiator staying cold while the rest heat up normally points to the valve as the first suspect. And if nothing warms up at all, anywhere in the house, that's worth calling someone about now, while they've still got space in the diary.
10 minutes in September is a much smaller job than a fortnight in December, when the same problem turns into an emergency callout in the middle of a cold snap.
radiators4u.co.uk