Turhan,

Absolutely it is not common to see an oven burnt out for three time in two years. 
We use a similar EA (EuroVector EA3028-HT, 1300'C) for H and O isotope analysis of water. For both analyses, we always use 1300'C as operating temperature with a power supply at 230V. We have not encountered such burnout problem so far.
The reason for this burnout could be a few: furnace itself; bad/wrong types of thermocouples; misplaced thermocouples; the way this furnace was used...
As Dr. River He has mentioned, Nick Collins at College Station, TX is very good at rebuilding such furnace and trouble-shooting. He should be able to help you figure this problem out promptly. 

Thank you,

Yi Wang (Ph.D.)
Director, Isotope Laboratory
ZymaX Forensics
600 S. Andreasen Drive, suite B
Escondido, CA 92029
Email: [log in to unmask]
Tel: 760-781-3338 ext 43
Fax: 760-781-3339
Cell: 609-721-2843
http://www.zymaxusa.com


-----Original Message-----
From: Stable Isotope Geochemistry [mailto:[log in to unmask]] On Behalf Of Turhan Dogan
Sent: Monday, November 02, 2009 6:44 AM
To: [log in to unmask]
Subject: [ISOGEOCHEM] EA HIGH TEMP OVEN BURNOUT, any solution?

Dear All,

We are mainly carrying out Oxygen and Hydrogen water sample anaysis with EA
EUROVECTOR EA3000, MKI-FURNACE, Max Temp:1300. 
We do water oxygen analysis with 1230 degree. The rectortor is ceramic
inside glassy carbon reactor with %30 Ni plated carbon powder.

Our problem is the high temp oven. It  burnt out three times in last 2 years. 

1.Is there any way to repair it?IT seems us difficult to repair.
2.Is it common that oven is burnt so frequently?
3.What teperature do you usually do oxygen analysis?Do you achive lover temp
than 1230_?
4.Do you have other alternatives for reactives for lower temerature?

Any information will be useful for us. It is an expensive part and 3 times
burnouts in 2 years cost. Considering future burnouts, we are trying to find
a solution other than just replacing it.

Best Regards
Turhan Dogan