Once the pipe is thawed and the boiler has been successfully re-started, you can lag the pipe with waterproof and weatherproof lagging to help prevent it re-freezing.
As a temporary measure, it may help to turn the boiler thermostat (not the room thermostat) to maximum and run the boiler in ‘continuous’ mode, turning the room thermostat to 15°C at night. Turn back to the normal settings once the cold spell is over.
In the longer term, in order to prevent the pipe freezing again, you can ask your Gas Safe registered installer to move the pipe so that it runs internally. Alternatively you could ask them fit a wider pipe, lag it to reduce the risk of freezing, install a trace heater along the pipe which warms it slightly when temperatures drop to freezing, or a combination of all of these.
British Standards, Building Regulations and boiler manufacturers’ instructions all provide information and recommendations that can advise your installer on how to run the pipe to reduce the risk of freezing.
Condensate pipe installation is also included in the Benchmark checklist that your installer should go through with you when he has completed your boiler installation.
Please watch our video on how to prevent frozen condensate pipes below.