Ignition transfer troubleshooting... Continuing our series on Navien, Inc troubleshooting and maintenance, we perform some basic troubleshooting on this combi unit NFC-250/175H. Ignition issues are simple to troubleshoot relatively speaking. If we have no power to our ignition transformer on a call, it could be a wiring issue or control board issue. If we have power to our transformer but no spark, most likely our transformer must be replaced. #hvac #hvactroubleshooting #combiboilertroubleshooti