"Rod Speed" wrote in message
...
You say "[the dual differential thermostat] somehow sensed the
temperature in the freezer" as if it was difficult or required ingenuity,
whereas surely each cabinet has its own bimetallic strip thermostat, set
to a different cutoff temperature, and then you either have two separate
compressors and separate refrigerant circuits or else if you want to cut
costs you have a single compressor, controlled by both thermostats using
"OR" logic, with one valve per cabinet, controlled by its thermostat,
which directs refrigerant where it is needed at that time - in the same
way that a central heating boiler that also heats a cylinder of water
usually has a single boiler and pump but valves to direct the heated
water where it is needed (CH / HW / CH and HW).

That obscenity of a sentence should be taken out the back and beaten
to death with the largest waddy you can find, before it multipys }-(
http://www.wordnik.com/words/waddy

Er, yes [blush] Did I really write that all as one sentence with barely a
pause for breath? Apologies for that. That rivals the opening sentence of
Oliver Twist in terms of being impenetrable and tortuous:

"Among other public buildings in a certain town, which for many reasons it
will be prudent to refrain from mentioning, and to which I will assign no
fictitious name, there is one anciently common to most towns, great or
small: to wit, a workhouse; and in this workhouse was born - on a day and
date which I need not trouble myself to repeat, inasmuch as it can be of no
possible consequence to the reader, in this stage of the business at all
events - the item of mortality whose name is prefixed to the head of this
chapter."

Gordon Bennett!

(not that I'm claiming to be anything like as profound as Charles Dickens)