Hello Everyone, I would like to thank everyone for their quick response and suggestions. Things appear to be OK at the moment (i.e., no more column deaths) so I suspect that we had a batch of bad columns that couldn't survive the cooling to standby (800°C) or cooling to room temperature for ash removal. To help prevent future problems and speed up ash removal I will start to use the liners as many of you suggested. Thanks again, Jennifer ------------------------------------------------------ Jennifer Mckay Agente de Recherche / Research Associate GEOTOP - Universite du Quebec a Montreal C.P. 8888, succursale Centre-Ville Montreal, Quebec, Canada H3C 3P8 Telephone bureau/office: 514-987-3000 (poste/ext 2413) Telephone lab: 514-987-3000 (poste/ext 7028) Telephone GEOTOP: 514-987-4080 Telecopieur/Fax: 514-987-3635 E-mail: [log in to unmask] or if that fails try [log in to unmask] ------------------------------------------------------