BoilerTroubleshooting2026-02-26
One Radiator Not Working: How to Fix
A single cold radiator usually means a stuck valve or trapped air.
When just one radiator stays cold, it's usually local to that radiator.
Common causes
A stuck thermostatic valve, a closed lockshield valve, or trapped air can stop one radiator heating.
What to do
Bleed the radiator and check both valves are open; a stuck valve pin can sometimes be freed, or the valve replaced.
Key takeaways
- Bleed the radiator first
- Check both valves are open
- A stuck valve pin is common
- Replace a failed valve
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