The replies to most of the questions during operation can be found in Trouble Shooting in Operation Manual or Process Manual; if not, please contact Landglass:

Please note: before the service engineer gives solution, he may need to know:
1. the model of your furnace;
2. at what conditions the problems happen and the detail description of the problems;
3. if the quality of the end products is concerned, please describe the quality problems in details, for example: the location of the white haze, how the glass bent, etc; meanwhile, please provide the tempering parameters during tempering.