Shimadzu Column Oven: CTO-10ASVP - Won't Cool

[akthmps]

We recently acquired a Shimadzu CTO-10ASVP column oven. We are operating it locally through the keypad, without any software control. I set the temperature of the column oven to 5C. Within a few minutes, the temperature dropped from about 25C to 15C. I left the oven, assuming it would continue to cool. When I came back 30 minutes later, it was back at 25C. I checked the settings to ensure it wasn't timing out, and it doesn't appear to be the case. Now when I set the temperature to 5C and watch it cool, nothing really happens. It doesn't seem to budge much from ambient temperature.

Any thoughts? If I look through all the configuration settings with the keypad, I notice the ambient temperature sensor is not installed. Is this required for the system to cool? It seems more like an optional feature that sends more information back to the data system if you so desire - but perhaps it's required to kick on the peltier? Does anyone know? I figured since it initially cooled to 15C without this sensor installed, that it wasn't required. I can't seem to find a service manual for this column oven online - does anyone have one or can provide a link?

Thanks so much for any advice!

-Aaron

[hplc.chem]

I have the same model and I quoted the below from the specification section in the manual:

" Temperature control range: (Room temperature – 15 oC) - (Room temperature + 60 oC)"
Room temperature was defined as " the ambient temperature near the CTO-10ASvp"

Therefore, the temperature that you can get depends on the ambient temperature around the oven.
I think you need to put the oven in a fridge to get the 5 oC!!

[akthmps]

It turns out that a connection had simply came loose. I opened up the column oven and one of the connectors leading to the peltier board was completely off. I reconnected and now it works properly. It was able to achieve 5C and I measured it with a thermocouple. It was within 1-2 degrees of the setpoint depending upon where you took the measurement. So, all is well now!