Loose A phase heater screw
hydrogen boiler infrared thermal imaging hydrogen boiler visible light
Infrared Thermal Image Visible Light Image
This screw is loose and that causes heat to build up. If there is a small gap caused by the loose screw then the wider the gap the more power needed to jump the gap. The more power used the hotter the connection.
This heater needs to be pulled and cleaned then reinstalled making sure that all wire connectons are tight.