Something wrong with temp control unit....it should shut off.
Jincheng Xiong's suggestion of source for parts from Omega is
good. Another place which might have parts (I can't remember the
name...they have or used to have a really neat lab calendar...)
I2R is the name? They sell Lead doughnuts and controllers....
>The liquid N2 tank is only works when you in there, if hapen in weekend,
>no body knows, who will turn on the tank.
Then leave it on all the time. When compressor pressure drops,
check valves will click into place and the tank will source the
nitrogen. (Just keep the tank regulator ~5 to 10 PSI below
Compressor). As long as the tank isn't too leaky and is not used for many
liftings of the sample, it should last a long time. Your gas provider might
be able to supply the valves.