Weil Mclain Ultra 105 gas boiler in Saugerties NY. Boiler was not operating due to multiple ignition failures. Removed heat exchanger plate to inspect and found 90% restricted. Cleaned entire heat exchanger. Removed all heavy debris then flushed with water. Reinstalled cover plate with all new gaskets. Started boiler and was operating very well! This boiler has not been regularly maintained. We recommend annual maintenance/inspection to ensure these failures don’t occur.