If your boiler is overheating you should turn it off immediately and call a Gas Safe-registered boiler engineer to come and take a look at it for you. If your boiler overheats this can cause serious damage to the internal components which can be very expensive to fix and may require the boiler to be replaced completely.
Generally speaking, there are two main reasons that boilers overheat and, if you catch these problems early, they can usually be solved relatively inexpensively.
Blockages
Overtime limescale, rust and other debris from your system can collect on the heat exchanger in your boiler and cause a blockage. This results in the flow of water across the heat exchanger being restricted, leading to a build-up of pressure. As the pressure in the boiler increases, it will get hotter and hotter ultimately causing it to overheat.
In modern boilers the built in safety controls should cause the boiler to automatically shut off if it starts to overheat. You will still need to get an engineer to examine the boiler for you to determine the reason for the fault and find a solution. Often this will involve powerflushing your system to remove the debris and allow the water to flow properly again.
Faulty controls
Sometimes overheating can be caused by something going wrong with your boiler’s controls. The controls regulate the flow of water and fuel for the boiler as well as checking its internal pressure and temperature. If these develop a fault you boiler can start drawing in too much water or fuel or can fail to stop heating when the required temperature is reached.
Either of these can cause your boiler to overheat and the controls will need to be checked by a qualified boiler engineer and may need to be replaced to get your boiler back into good working order.
Keep a cool head and call DHS!
DHS have been offering reliable and cost-effective boiler repairs in Bristolfor over 40 years. Every engineer we use is employed directly by us and is Gas Safe-registered with all the appropriate training and qualifications. That means you can have complete confidence in the quality of our work and rest easy in the knowledge that your boiler is in safe hands.
Unit 2 Septimus Buildings 
