Cooling is not happening

Hello, 

We do have ploystat CC1 Chiller( SNr:58212/04) using laser cooling purpose. we entered setup value 20 degrees but some other reason it is not reaching that point but steadily going up like 21,22 23 c. I presume chiller is not working properly, cooling LED is not blinking but we can see the continuous glow. I did not find any info regarding this problem at manual, Please kindly can you help us how to resolve this problem 

Sincerely, 

Ragava