I have been using the heater successfully (thanks to your help). However today the controller wouldn't turn on. I had a look and coming from the back of the controller, there is a red wire and a brown wire that has come loose. It looked like the brown was connected to 2 negative black wires so I reconnected those. The red however I'm not sure - I have connected it to another positive and the heater comes on automatically and won't turn off which isn't how it usually behaves. However I can't see anywhere else I haven't tried. It's the bottom left and bottom middle wires in the image marked in blue. Can you please advise at all?

