1. The limit switch associated with the door or lid of the pit-type furnace must ensure that the main circuit is de-energized once the door or lid begins to move.
2. Before operating the pit-type furnace, ensure that power connections make good contact and that the power cable insulation meets requirements.
3. Gas flow meters and pressure gauges on controlled-atmosphere resistance furnaces must provide accurate and responsive readings.
4. Resistance furnaces utilizing flammable atmospheres must be equipped with furnace temperature alarms and necessary interlocking devices to prevent explosions.
5. The grounding bolt on the furnace body must be secure and reliable.
6. Water-cooled pit-type furnaces must be equipped with relays for monitoring water temperature, pressure, and flow rate; these must cut off the main circuit power and trigger an alarm signal in the event of any abnormality.
7. Explosion-proof safety devices on controlled-atmosphere furnaces must operate reliably and responsively.
8. Exposed electric heating elements on the exterior of the furnace shell must be fitted with safe and reliable protective guards.
