Cryostar low temp freezer problem

[mikebry]

I have a customer with a Cryosrar Mod QC10140W15
It's been running at -140 for 5 years he only want's
-120. I should think that the temp probe or the controler
is faulty. Has anyone any tec data sheets on this or
knows where I can find the info. I've searched the net
without much sucess. Thanks

[norseman]

I have a customer with a Cryosrar Mod QC10140W15
It's been running at -140 for 5 years he only want's
-120. I should think that the temp probe or the controler
is faulty. Has anyone any tec data sheets on this or
knows where I can find the info. I've searched the net
without much sucess. Thanks

Hi Mikebry.

This type of units are mainly made to keep products stored at a temperature below the glass transition temperature of approx -130c. It seems strange to use this expensive single cascade unit at a working temperature as high as -120c. Harris looks pretty similar to Revco regarding the control panel. I am not sure if the system is made so the setpoint is locked to -140c. Did you try to enter the set menu and really got a new set of -120c?
Anyway, such autocascade systems mostly using 5 gases on a single stage should normally work at the operation temperature they are sceduled to handle. Both the system pressure and cooling capacity are out of a good range if they work "outside"
The company to try is the head company Thermo- scientific or Thermo-Fisher. I thought that those units just was for the US. market only and Devon is GB is it not? If GB I suppose they have a department there, if not, they have a department in Germany.
You can also find Harris on the US www. for Thermo.