Disconnect Switch
hydrogen boiler infrared thermal imaging hydrogen boiler visible light
Infrared Thermal Image Visible Light Image
This is a loose wire connection. Notice how the wire cools off as it gets farther away from the screw connection. Also notice that the fuse clip is showing a lot of heat. The spring tension in the fuse clip starts to fade away when the fuse clip reaches approx. 200 degrees, and after that the only cure is replacement.
 
This can all be averted by cleaning and tightening the wire connection.
We would never know about this condition without Infrared Thermal Imaging.