Removing an air lock from your central heating system involves several steps, primarily focused on bleeding the system to release trapped air. Here's a comprehensive guide:
1. Identify Symptoms of an Airlock
Before proceeding, confirm you have an airlock. Common signs include:
- Radiators not heating up properly: Some radiators may be cold or only partially warm, especially at the top.
- Noisy pipes: Gurgling or banging sounds coming from the pipes.
- Boiler shutting down: The boiler might overheat and shut down due to poor circulation.
- Pump running constantly: The pump might be working harder to circulate water.
2. Preparation & Safety
- Turn off the boiler: Let the system cool down completely before starting any work. This prevents scalding.
- Protect surfaces: Have towels and a container ready to catch any water that escapes during the bleeding process.
3. Bleeding the Radiators
This is the most common method to remove airlocks:
- Locate the bleed valve: This is usually a small valve located at the top of one end of each radiator. It often requires a radiator key (a small square wrench).
- Insert the radiator key: Fit the key into the bleed valve.
- Open the valve slowly: Turn the key counterclockwise gradually. You should hear a hissing sound as air escapes.
- Close the valve: Once water starts to come out steadily (without air), close the valve tightly. Do not overtighten.
- Repeat for all radiators: Start with the radiators furthest away from the boiler and work your way back. Check the pressure gauge on your boiler after bleeding, and top up the system's pressure if necessary.
4. Other Methods for Removing Airlocks
If bleeding the radiators doesn't solve the problem, consider these methods:
- Booster Pump (for stubborn airlocks): Sometimes, a temporary booster pump connected to the system can force air out. This is best left to a professional.
- Automatic Air Vents (AAVs): Some systems have AAVs installed at high points. These automatically release trapped air. Check that these vents are not blocked or malfunctioning.
- Magnaclean Filter Bleed Valve: If you have a Magnaclean filter installed on your system, bleed the valve located on it to release any trapped air and debris.
5. Addressing Airlocks Near the Pump
Airlocks can occur near the pump.
- Locate the pump: Find the central heating pump, often found near the boiler.
- Check the pump's bleed screw: Some pumps have a bleed screw that can be opened to release air. Carefully loosen the screw until air escapes, then retighten when water appears. Be extremely cautious when working near the pump. Ensure power is OFF to the pump before attempting to release air.
6. Professional Help
If you've tried these steps and the problem persists, it's best to call a qualified heating engineer. There might be a more complex issue, such as a blockage in the system or a faulty pump.
