I. Installation Instructions
1. After unpacking, inspect the muffle furnace to ensure it is intact and undamaged, and verify that all accessories are present. Most standard muffle furnaces do not require specialized installation; they simply need to be placed levelly on a flat indoor floor or shelf. The controller should be protected from vibration and positioned at a sufficient distance from the electric furnace to prevent internal components from malfunctioning due to overheating.
2. Insert the thermocouple into the furnace chamber to a depth of 20–50 mm, and pack the gap between the insertion hole and the thermocouple with asbestos rope. When connecting the thermocouple to the controller, it is best to use compensating wires (or insulated steel-core wires); pay close attention to the positive and negative terminals to ensure they are not reversed.
3. An additional power switch must be installed at the power inlet to control the main power supply. To ensure safe operation, both the electric furnace and the controller must be reliably grounded.
4. Before use, adjust the temperature indicator gauge to the zero point. When using compensating wires and a cold-junction compensator, the mechanical zero point should be adjusted to the reference temperature point of the cold-junction compensator. If compensating wires are not used, the mechanical zero point should be set to the zero mark on the scale; however, in this case, the indicated temperature will represent the temperature difference between the measurement point and the cold junction of the thermocouple.
5. After inspecting the wiring and confirming that it is correct, secure the controller housing cover. Adjust the setting pointer on the temperature indicator gauge to the desired operating temperature, then connect the unit to the power supply. Switch on the main power switch; at this point, the green light on the temperature indicator gauge will illuminate, the relay will engage, the electric furnace will begin drawing power, and the ammeter will display a current reading. As the internal temperature of the furnace rises, the pointer on the temperature indicator gauge will also gradually ascend; this phenomenon indicates that the system is functioning correctly. The heating phase and the constant-temperature (holding) phase of the electric furnace are indicated by the red and green lights on the temperature indicator gauge: the green light indicates that the furnace is heating up, while the red light indicates that it has reached and is maintaining the set temperature.
II. Precautions
When using the muffle furnace for the first time, or after a prolonged period of inactivity, it is mandatory to perform a drying bake-out: dry with the furnace door open at 20–200°C for 2–3 hours, then with the door closed at 200–600°C for another 2–3 hours.
Before conducting an experiment, ensure the temperature controller is free from vibration; do not position it too close to the electric furnace, as overheating may prevent the electronic components from functioning correctly. When moving the temperature controller, the power switch must be set to the "Off" position.
Prior to use, set the temperature controller to the desired operating temperature and activate the start control to energize the muffle furnace. At this point, the ammeter should display a reading, and the actual temperature value shown on the controller should begin to rise gradually; this indicates that both the muffle furnace and the temperature controller are functioning normally.
(I) Operating Environment: The working environment must be free of flammable or explosive materials and corrosive gases. It is strictly prohibited to pour any liquids or molten metals directly into the furnace chamber. The interior of the furnace chamber should be kept clean at all times.
(II) Operation Limits: During use, the temperature inside the furnace chamber must not exceed the maximum rated furnace temperature, nor should the unit be operated continuously at its maximum rated temperature for extended periods. During an experiment, the user must not leave the vicinity; constantly monitor temperature fluctuations. If any abnormal conditions are detected, immediately cut off the power supply and arrange for inspection and repair by qualified professional maintenance personnel.
(III) Door Handling: Open and close the furnace door gently to prevent damage to the mechanical components. When inserting or removing samples using crucible tongs, handle them with care to ensure safety and avoid damaging the furnace chamber lining.
(IV) High-Temperature Operation: Do not open the furnace door when the internal temperature exceeds 600°C. Wait for the temperature inside the furnace chamber to cool down naturally before opening the door.
(V) Post-Experiment Procedure: Upon completion of the experiment, remove the samples from the heating zone and switch off the power supply. When retrieving samples from the furnace chamber, first crack the door open slightly; wait for the samples to cool down somewhat before carefully grasping them with tongs to prevent burns.
(VI) Cooling Heated Crucibles: Heated crucibles should ideally be transferred to a desiccator for cooling. Place them on a heat-resistant buffer material to prevent moisture absorption—which could lead to cracking or shattering—before proceeding with weighing.
(VII) Transport and Placement: When moving the muffle furnace, take care to avoid severe vibration or mechanical shock. Position the unit away from flammable or explosive materials, water sources, and similar hazards. It is strictly forbidden to lift the furnace by grasping the door, as this may result in damage to the door assembly.