Before Furnace Ignition: What to Confirm on Electrode Cooling and Power Supply

A furnace pre-ignition checklist is usually long, and the electrode system often sits near the end of it. Once ignition has taken place, the room to fix a cooling or power problem is limited, so the relevant checks should be gone through separately beforehand.

Cooling Water First, Then Power

Confirm that water jackets, hoses and joints show no leakage, that flow and pressure are within the set range and that the return water temperature is normal. Establish cooling water circulation before energizing so the electrode does not heat up without cooling. Keep the water clean to prevent scale depositing in the high-temperature section and impairing heat transfer.

Power Circuit and Connections

Check cables, clamps, insulation parts and earthing, and confirm that contact surfaces are clean and tightening torque meets the requirement. Three-phase currents should be essentially balanced; if the deviation is large, check the connections and electrode condition first rather than raising the setpoint directly. Test each protective interlock in turn and confirm it operates reliably.

Electrode Position and Sealing

Verify insertion depth, spacing and angle, and confirm the sealing material is properly installed. Control the gap between electrode and brickwork according to the drawing; if it is too tight, additional stress develops as temperature rises. During ignition and heating, arrange inspection rounds, record current and cooling water parameters, and reduce load promptly if an abnormality appears.

Joint Confirmation Before Ignition

The electrode system involves electrical, instrumentation, water treatment and furnace process disciplines, so a joint confirmation before ignition is advisable, going through the checks each discipline is responsible for. Record the results on one sheet with the inspector and time noted, so nothing is missed in verbal handover.

During ignition and heating, cooling water temperature and current changes should be logged continuously. If the water temperature rises while flow is normal, check first whether the jacket is scaled or blocked; if the current drops suddenly, check the connections and electrode condition rather than raising the setpoint blindly.

The pre-ignition confirmation sheet can be stored by furnace type and amended at the next maintenance, which reduces repeated drafting.

For a furnace that has been shut down for a long period, also check the electrode surface for oxidation or deposits before ignition, and clean if necessary before energizing. After prolonged idling, allow a longer period of low-load observation on first heat-up.

In the first few shifts after ignition, step up observation; if the current is abnormal or the water temperature rises, shut down and inspect promptly.

For electrode structure and cooling methods, see the selection notes for this duty; for purchasing and technical support, see the manufacturer information.