Tony Williams wrote:
In article ,


I assume you are talking about a side-by-side? If you have an ice
machine in the freezer, be sure to turn this OFF until you
return to normal operation.


I don't know if it is a type of fridge-freezer that
you would see in the US Fred. The fridge and freezer
compartments are above each other, both with their
own doors. The cheapest models use a single compressor,
which is controlled by a thermostat in the fridge only.
The fridge is controlled to run at just above 0C and
the freezer compartment runs at 'minus something' just
by circulating air around the coldest part of the coils.

The design suffers from two major faults. The first
one is the one that Terry has recently experienced,
freezer compartment defrosting due to blocked airflow.
The second problem is more subtle.... if you install
such a fridge-freezer in an environment which runs at
lower than about 18C then the freezer compartment can
also warm up. This is because, at 18C ambient, the
fridge, (which is doing the controlling), doesn't run
the compressor enough to keep the freezer compartment
down at it's 'minus something'.

That second problem often occurs with 1-compressor models
kept (say) in an unheated garage, during winter months.


Right- that type of machine is called a top-mount in the U.S. There are
actually such things as bottom mount, freezer vertically below the
"fresh food" compartment, the theory being that you bend down less
frequently to retrieve food from the freezer than the fresh food
compartment. As for temperature regulation, the industry standard is a
-10oF evaporator temperature, this is the design saturation liquid/vapor
point which I'm sure holds true in Europe as well. The efficiency of low
temperature compressor designs drops off exponentially with low pressure
so that you will find a 1/4 HP compressor barely achieving 800BTU/HR
rating at low temp where the same HP may hit several thousand BTU/HR in
a medium temp application, such as a simple beveridge cooler, with +20oF
evaporator temperature. In the standard top mount situation, it is the
air temperature in the fresh food compartment that is regulated, and the
freezer temperature control is usually tied to a vane which sets the
proportion of air between the freezer and fresh food compartments. At
colder freezer temp setting more air is circulated within freezer etc.
You will find that you have quite a complicated little styrofoam
airchannel arrangement beneath the plastic partition separating the
fresh food and freezer compartments, and that is why you have to use a
heat gun cautiously when you do a forced defrost as this channel is
easily melted:-) In this particular case, because the model is
GE/HOTPOINT, the compressor design is most likely their infamously
short-lived rotary with powdered metal parts- this means that unless TP
finds a hard failure such as completely iced evaporator, non functioning
condenser fan, or condenser coil completely blanketed with debris, then
one of two things is occurring: 1)compressor has lost recovery capacity
and should be replaced, or 2) initial refrigerant charge contained too
much H2O which has been forced from the filter/dryer by the excess heat
and is now freezing and blocking the evaporator refrigerant capillary
feed. In case 2), it may return to normal in time under light loading,
allowing the dryer to re-absorb the water.