why HPLC column oven doesn't heat

[AUlee]

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

[JGK]

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.

[LCbob]

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 ).

[tom jupille]

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.

[AUlee]

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