Plumbing Advice

Removing an Airlock from a Central Heating System

If you discover that you have an air lock within your central heating system there are a number of methods that you can try before contacting a professional plumber. If you are able to remove the air lock yourself you can save the cost of calling a plumber out to fix the problem.

How Can I tell if there is an Air Lock in my Central Heating?

An air lock occurs when air gets trapped inside your heating system resulting in no heating. The most common cause of an air lock is that your radiators were recently drained and refilled in the wrong sequence or that air has entered the system somehow.

The most common place for air to get trapped is within your radiators. You will notice if air is trapped in your radiators as there will be a reduction of heat produced.

The air will rise to the highest level in the system which is why it gets trapped in radiators. If the top of the radiator is noticeably cooler than the bottom, it is a good sign that there is air trapped in them.

If you have had your heating system refilled and you neglected to close off the upstairs radiators whilst filling the downstairs radiators then it may be easier to drain the system down and begin again.

How to remove an Air Lock in your Heating System

Check that your pump is working

Your problem may be caused by the pump not working correctly. If it appears to be working, try to turn the pressure up to help move the airlock.

Check your radiators

You will need to keep at least one radiator on at any time whilst checking them. Turn on the boiler and test one radiator at a time to check that it is warming up efficiently. When you are satisfied that the radiator is working correctly, move onto the next radiator.

You should always ensure that the previous radiator remains on whilst turning on the following radiator. Once you have moved onto the next radiator you can turn of the first.

Isolate faulty radiator

If a single radiator is causing the problem, you can turn the problem radiator off which will allow additional water pressure to reach the other radiators.

Check radiator balancing

If you have checked all your radiators and they work individually but then the heat diminishes once they are all turned on, this may be a problem with balancing.

Balancing is caused by a badly installed heating system. You can rectify a balancing problem by closing the valves to 50% or until the problem is solved.

Refill your heating system

First drain your heating system completely. Refill your central heating from the lowest point upwards.

Check the colour of the water

If you have black water in your system then you will need to arrange for a power flushing. Black water indicates that the blockage is caused by a dirt build up and not an air lock.

Plumbing and Heating in Lancashire

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