The temperature of the vertical graphite carbon tube vacuum furnace cannot rise

10-17-2025       Author: KJ technology

The temperature of the vertical graphite carbon tube vacuum furnace cannot rise, which may be caused by power failure, temperature controller failure, damaged heating elements, insufficient vacuum degree, thermocouple failure, sealing problems, etc. The following are specific analysis and solutions:

1. Power failure

Possible cause: Malfunction in the power supply line or switch, resulting in the inability to transmit power to the heating element normally.

Solution:

Check if the power lines and switches are functioning properly, ensuring there are no open or short circuits.

Use a multimeter to check if the power supply voltage is stable and meets the equipment requirements.

2. Temperature controller malfunction

Possible cause: Incorrect or faulty temperature controller parameter settings, resulting in inaccurate control of heating temperature.

Solution:

Check if the temperature controller parameter settings are correct, and refer to other temperature controllers in normal use for calibration.

Use a multimeter to check if the output signal of the thermostat is normal. If there is a malfunction, it needs to be replaced or repaired.

3. Heating element damaged

Possible reasons: Heating elements (such as graphite carbon tubes) may be damaged due to aging, overheating, or mechanical damage, resulting in the inability to heat properly.

Solution:

Use a multimeter to check if the resistance value of the heating element is normal. If it is abnormal, it needs to be replaced.

Check if the connection of the heating element is tight, without looseness or poor contact.

4. Insufficient vacuum degree

Possible reasons: Vacuum pump malfunction, aging or damaged seals, pipeline blockage, etc., resulting in insufficient vacuum in the furnace and affecting heating efficiency.

Solution:

Check the operating status and sound of the vacuum pump for normal operation. If there is a malfunction, it should be repaired or replaced in a timely manner.

Observe whether the seals are aging or damaged, and replace them if necessary.

Use a vacuum gauge to measure the vacuum level and check if the pipeline is unobstructed. If there is any blockage, it needs to be cleaned.

5. Thermocouple malfunction

Possible cause: The thermocouple wire is broken or short circuited, which makes it impossible to accurately measure the temperature inside the furnace.

Solution:

Use a multimeter to check if the resistance value of the thermocouple is normal. If it is abnormal, it needs to be replaced.

Check whether the connection of the thermocouple is tight, without looseness or poor contact.

6. Sealing issue

Possible reasons: Poor sealing of the furnace body, loose or damaged flange connections, etc., causing external air to enter the furnace and affecting the heating effect.

Solution:

Use soap water or a leak detector to conduct a leak test on the furnace body, with a focus on inspecting the sealing surface and flange connections.

If a leakage point is found, it is necessary to repair or replace the seal in a timely manner.