FAQ - Frequently asked questions

1- Where should the zone control thermocouples be located in a reheat furnace?
Always on the roof (never on the walls), exactly vertical, in the exact centerline between 2 adjacent burners and as near as possible to the centerline of the furnace chamber. The thermocouple is normally located about 2/3 of the way through the zone.

2- How should the air/fuel ratio be adjusted?
By having an experienced look at the flames, it is easier, better, and more precise than measuring oxygen, carbon dioxide or carbon monoxide which can give false readings due to stratification or sampling errors.

3- When should the burners be balanced?
Every month until it is ensured that the balance holds for 2 months or more.

4- Why do recuperators need protection?
Because recuperators are subject to damage from overheating. With a good protection scheme it is possible to increase their life from 2 years to 10 years or more.

5- Who should be in charge of the zone temperature set points?
Only a good level 2 control system could decide the correct set point, based on the discharge rate and products being heated.

6- What does "cut-off" mean?
This is a control feature that will cut off the fuel and reduce the air to its minimum value when the burners reach the lowest point of their "turn-down ratio".