"Linear" wrote:

Most likely the freezer is working properly. When the door was open it
allowed enough ice built up on the freezing coil to impede the air flow.
The temp sensor then doesn't report the temp of circulating air (which is
very little) but rather the temp near the now frozen coil. The solution is
to do a complete and thorough defrost. If necessary use a hair dryer to
make sure the coils are completely dry before turning back on. This was a
very common problem in some early window air conditioner units about 30 to
40 years ago.

Let us know what you find out.

Thans for all the input guys. It proved to be as Linear suggested. I
probably went OTT by dismantling the panels, but that hastened the
thaw. Used hair dryer, then placed 3 kW fan heater in position for an
hour.

Re-assembled and set it to Fast Freeze. An hour later it was going
well, down to -7C, and this morning -25C! Now returned to normal
setting. I can put away the catalogues for a while now g.

Much appreciated the help.

--
Terry Pinnell
Hobbyist, West Sussex, UK