-70°c problem

[Sven]

Haj all there, refrigeration-engineers,

I've installed a freezer of +-30m³ for the european commission which has to reach -70°c. We can only reach a temperature of -65,8°c. This cell is placed in another freezing cell of -20°c We cannot find out where the problem lies but when we put of the cooling system of the -70 cell we get a temperature rise of +-10°c in +-1 hour.
Is this normal?
We also think that the compressor have not enough power to freeze the cell down? Can somebody help? I will be happy to send someone the whole story because we believe we've got a lot of problems with this cells.

TNX

[rbartlett]

We have the technical expertise to assist you but

1 we would have to charge all expenses etc for this to be able to sign our names to it
2 we may not be able to undertake this for a while due to the recent high temperatures/workload


cheers

richard

[Peter_1]

Well, as I am also from Belgium and have some expertise in low temperature applications (installed some cascade systems down to -100°C), you can send me the whole story.
BTW, what company are you working for?

[benijoseph]

Mr,7,
If you can take all readings like 1, pressure reading of all guages 2, gas used in both the system (main coolig and cascade) 2, total tonnage what you are using, 3, Insulation used and thicknes of it or how long cooling remains inside the unit after switching of the unit 4, condensor is of which type ? 5, compressor type ,model , name 6, ambient temp of your place.
you can post these reading or e-mail it to me , I will try to help you .I work on chamber's which have lower then this temperature.
with kind regards
beni joseph,
e-mail beni.joseph@ rediffmail.com

[botrous]

Why don't you attach or post the whole story so we can have a team work to solve your problem , it would be nice to do that.