BoilerMaintenance2026-02-28
Using a Radiator Key to Bleed Air
A radiator key and a cloth are all you need to release trapped air safely.
Bleeding radiators with a key is a simple task that restores even heat.
What you need
A radiator bleed key (inexpensive at any hardware store) and a cloth to catch drips.
How to do it
With the heating off and cool, turn the bleed valve until air hisses out and water appears, then close it and check boiler pressure.
Key takeaways
- Use a radiator bleed key
- Heating off and cool first
- Stop when water appears
- Re-check boiler pressure
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