Hiya, my 99-420 has a basic Truma heater, the control knob is really stiff? The heater fires up fine and works a treat but anyone have any ideas as to why the knob is so tight to turn??
I can see this unit has had very little use in its life. I opened the door and cleaned out a little dust.
Rgds Mike.

Join a gym

The front of the heater lifts up and comes off, then you can give it a little squirt of WD 40 or similar and give it a really good clean with the hoover attachment
around and about and underneath.