Have you already seen the troubleshooting guide for this issue? If not, you can find it here:
forum.langmuirsystems.com/t/torch-not-firing-troubleshooting-guide/1936
If you notice anything out of the ordinary after following along with the troubleshooting guide, reach out to support@langmuirsystems.com and let them know what your voltage reading was at which step, we can help you from there!