Chromatography Forum

Hi all,

I came across HPLC column oven doesn't work recently. One day, HPLC was running on 85 degree C. When I came back after 3 hours and suddenly found that the temperature is only 60 C. It's keep decreasing and the oven heat function lost completely even though I restart it.

BTW, the column oven model "CTO-20A prominence" and is only used around 2 years.
what should be the problem?

thanks and have a great day!
lee

http://www.ssi.shimadzu.com/products/pr ... ct=cto-20a

Given that the CTO20A has a maximum operational temperature of 85C, I would suspect that the heating control is not working.

Not sure about this model but the earlier models used to run the cables through the door hinge, check to see if there is wear ( disclaimer not sure on this model ).

I've never worked with that particular unit, but that kind of failure has to come from one of three things:
- the heater is burned out
- the thermostat/controller electronics module has failed
- the temperature sensor has failed
or, a bad connection between these modules.

Per LCBob's suggestion, look in the "obvious" places for frayed cables. If nothing jumps out, open up the chassis and unplug/reconnect all the connectors (sometimes they vibrate loose). Check to see if there is a fuse (maybe in the heater circuit?) that has blown.

If there's no joy at that point, then it's a hardware failure. If you have another oven of the same model, try swapping the parts around (thermistor / heater / controller) to find out which is bad. If you don't then it may be cheaper to get a service tech in to look at it, because otherwise you're going to have to swap in new modules.

Thanks so much for your replies.

One technician from shimazu fixed it. He said it's caused by long time high-temperature using. One part of the device (probably a connecting part, I don't know exactly) become loose. When he push somewhere hard, the oven heats. But gently push, no heating at all. So, finally he tight somewhere. It works good till now.

Have a great day.

Lee