Meltdown! How to avoid a furnace disaster by using the safety features of the furnace system
No one wants to hear “furnace” and “disaster” in the same sentence. Your new Deltech furnace control system was supplied with a limit controller to help you avoid one kind of catastrophe. A limit controller is a relatively inexpensive device that prevents power from going to the furnace if a setpoint temperature is exceeded. However, today you desperately need to fire product, and you have misplaced the thermocouple which signals the limit controller. Without the thermocouple in place and operational, the limit controller prevents the contactor from engaging, preventing current flow to the system. So – because you are desperate – you bypass the controller and run the furnace, relying on the programmable temperature controller and control thermocouple to perform reliably.
But remember Murphy’s Law: disaster strikes! Your control thermocouple wires unite, resulting in a signal being generated from a point distant from the center of the furnace hot zone. So the temperature controller – the brain of the system – is being told that the furnace temperature is much lower than the setpoint, and it signals the power controller accordingly. The furnace temperature increases beyond the maximum operating temperature of the furnace. Your furnace insulation melts. Your product is a puddle. And maybe your elements have all failed. You have lost money and you will experience considerably more downtime than the time it would have taken you to locate the missing thermocouple. Never, but never, disable your over temperature protection circuit! Deltech control systems are certified by Intertek to be UL508A listed. Over temperature protection circuits are one of the requirements for that listing, and you can now see why.
If you need to add overtemperature protection to an existing system, contact us for information and pricing on this important safety upgrade.