Electric heating vacuum brazing furnace cannot be vacuumed up

09-24-2025       Author: KJ technology

The vacuum cannot be drawn up from the electric heating vacuum brazing furnace, which may be caused by various factors such as vacuum pump failure, aging and damage of seals, leakage, heating element or control system failure, cooling system problem, controller or sensor failure, etc. The following is a detailed introduction:

Vacuum pump malfunction:

Pump oil contamination: The pump oil is contaminated or too thin, causing poor operation or damage to the vacuum pump.

Pump overheating: Long term operation causes the pump to overheat, and the expansion of the components leads to insufficient clearance.

Improper cleaning: debris enters the oil, affecting the performance of the vacuum pump.

Solution: Clean the vacuum pump, replace with new vacuum pump oil, repair or replace damaged vacuum pump parts.

Aging or damage of seals:

Seal aging: Seal aging, corrosion or damage, resulting in poor sealing.

Loose pipeline connection: Loose pipeline connections, leakage of electromagnetic valves, pipe joints, vacuum pump suction valves, and sealing gaskets around the working chamber.

Solution: Check and replace aging or broken seals to ensure good sealing, inspect pipeline connections, solenoid valves, pipe joints, etc., and repair or replace them.

leak:

External leakage: Larger leakage points can be detected using flame detection. Based on the principle that airflow can cause the flame to deviate, a vacuum is first drawn and a candle or lighter is used to gradually search near the suspicious point. If the flame deviates towards the leakage point, the leakage point can be found.

Internal leakage: Internal leakage often occurs on equipment with water cooling points. No suspicious points were found during the inspection of external leakage, but the pumping speed of the mechanical pump is significantly low, the vacuum gauge reading is low, the mechanical pump oil quickly emulsifies, and the iron-based components in the vacuum chamber are obviously corroded. With the above conditions, internal leakage can be basically diagnosed.

Solution: For external leaks, locate the leak point and repair it; For internal leaks, first clean the cavity thoroughly, then add cooling water and carefully inspect the water pipeline for any wet spots. Wet spots are the leakage points, and then repair them.

Heating element or control system malfunction:

Heating element damage: Heating element aging, damage or poor contact, heating strip burning out, heating wire burning out.

Control system malfunction: temperature controller damaged or improperly set, thermocouple wire disconnected or short circuited, temperature control instrument malfunction.

Solution: Check the connection and resistance of the heating element, repair or replace damaged heating elements; Check and adjust the settings of the thermostat, replace or reconnect the thermocouple, and repair the control system.

Cooling system issues:

Insufficient cooling water supply: Blockage in the cooling water pipeline or insufficient cooling water supply can affect the performance of the vacuum pump.

Solution: Check if the cooling water pipeline is unobstructed, ensure sufficient cooling water supply, and clean any blockages.

Controller or sensor malfunction:

Controller setting error: The controller setting error caused the vacuum pump to malfunction.

Sensor malfunction: Sensor malfunction prevents accurate detection of vacuum level.

Solution: Check the settings of the controller to ensure that the parameter settings are correct; Check the working condition of the sensor and replace the faulty sensor if necessary.