Sometimes furnace failure occurs due to factors like system or human errors. How do you prevent this from happening?
No one needs to hear “furnace” and “failure” in the same sentence.
Your greatest asset (it may not be what you think)
Furnaces are equipped with limit controllers to assist you in avoiding terrible events. A limit controller is a low-cost device that cuts off power if a setpoint temperature exceeds the limit.
Without the thermocouple operational, the limit controller prevents the thyristor or contactor from engaging, preventing current flow to the system.
Finding the root cause of the issue
Sometimes you bypass the controller and run the furnace, depending on the programmable temperature controller and control thermocouple to perform reliably.
If your control thermocouple wires join together, a signal is produced from a point removed from the centre of the furnace’s hot zone. The temperature controller is informed that the temperature is much lower than the setpoint, and it signals the power controller accordingly.
When the furnace temperature increases beyond the maximum possible operating temperature, your furnace’s insulation dissolves along with the metal. Your elements may all fail. You lose money and experience far more downtime than the time it would have taken to locate the missing thermocouple.
Never, ever disable your over-temperature protection circuit.