If you believe that you may be experiencing this issue, the following step-by-step guide might be able to help. You may have to repeat the process a few times.
Hold a hot water bottle, or heat wrap around the pipe.
Pour hot water over the frozen end of the pipe. Make sure that the water is not boiling hot.
If you think that this may have worked and the pipe is no longer frozen, switch the boiler on again. You may need to reset it.
If the boiler springs to life, you've fixed it! If it doesn't however, you may need to repeat this process.
If it is not possible to unfreeze your condensate pipe, please give us a call and we can arrange an engineer visit.
This video may help as well.