Very helpful to share ozone answer to Gill Bowyer (November 2011). We followed your instructions fully.
Defrost successfully completed, and we switched back on after 24 hours at Number 4. Works well but has now frozen up in the upper region of the back wall.
My fridge is certainly older than 3/4 years.
Would it be helpful for you to "take us through the evap timer circuit?"
Many thanks

Barbara Pearce, October 2013