Radiator cold at the bottom?
See what might cause a cold patch and what to check before choosing a fix.
Read the cold radiator guideHeating Help
Heating problem? Let’s work out what to check.
Radiator cold at the bottom, black water, or worried about sludge? Start with a practical guide, or tell us what you’ve noticed and we’ll help you choose a sensible next step.
What do you need help with?
The same symptom can have different causes. These guides explain what may be going on and what details are useful to share.
Black radiator water?
Find out what dark water may mean and which other checks can help.
Read about black radiator waterCould there be heating system sludge?
Explore cold spots, slow circulation and other signs before deciding on cleaning.
Read the cleaning guideMore practical heating guides
Buying a home? See the heating checks to make before buying a house.
Further reading: Heating-water care and BS 7593 · Boiler warranties and heating water.
Still need a hand?
Tell us which rooms or radiators are affected, when the problem started and whether anything has changed recently. We can help you choose where to start.
Know what you need?
Read about CleanFlow heating work or browse common questions.
For an emergency or urgent safety concern, use the appropriate emergency service or a suitably qualified professional. See our safety information.