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Common faults and solutions of vacuum aluminum brazing furnace

06-12-2025       Author: KJ technology

The common faults and solutions of vacuum aluminum brazing furnace are as follows:


1. Temperature control related faults

The temperature cannot be stabilized at the set value, fluctuates greatly, or the displayed temperature does not match the actual temperature

Possible reasons: thermocouple wire breakage, damage, or incorrect installation position; Temperature control instrument malfunction; Heating element aging, damage or insufficient power.

Solution: Replace the thermocouple with a new one and ensure its accurate installation position; Perform maintenance or replacement according to the temperature control instrument manual; Check the heating element, such as whether the graphite heating tube is contaminated and whether the resistance value has increased. If there is a problem, replace it in a timely manner and ensure that the resistance of the new graphite tube matches the voltage regulator.

Slow heating, heating power not reaching rated value or unable to heat up

Possible cause: Magnetic regulator malfunction; Heating element short circuit or open circuit; The power supply voltage is unstable or lacks phase.

Solution: Check the magnetic voltage regulator for loose wiring and normal contacts; Check the resistance value of the heating element and replace the short circuited or open circuited heating element; Use a voltage regulator to stabilize the power supply voltage and check for any phase loss issues in the electrical circuit.


2. Vacuum related faults

Unable to reach the maximum vacuum degree or vacuum degree decrease, leakage

Possible reasons: aging, damage, or improper installation of seals, leading to furnace leakage; Vacuum pump malfunction, such as low pumping efficiency, oil contamination, and worn shaft seals; There are air leakage points in the vacuum system, such as poorly sealed valves and loose pipeline connections.

Solution: Check and replace aging or damaged seals to ensure correct installation; Repair or replace the vacuum pump to eliminate oil pollution, wear and tear issues; Perform leak detection on the vacuum system, identify the leak points and repair them, such as replacing valve seals, tightening pipeline connections, etc.

The vacuum cannot be drawn up

Possible reasons: Insufficient pumping capacity of the vacuum unit or high leakage rate.

Solution: Check for leaks in the vacuum pump and valves, whether the diffusion pump oil is contaminated or oxidized, whether the front-end pipeline is well sealed, whether the pump oil is sufficient, whether the pump oil is emulsified, and whether the shaft seal is leaking oil.


3. Malfunctions related to transmission components

Fault manifestations: The transmission components are not flexible in operation, there is abnormal noise, the limit is malfunctioning or unable to reach the predetermined position.

Possible reasons: gear wear, poor lubrication; Motor malfunction; Damage or improper adjustment of limit switches; Loose coupling or different shafts.

Solution: Check the operation of the motor and reducer, and promptly repair any problems; Check the lubrication of transmission components such as chains, sprockets, and bearing seats. If there are any problems, add lubricating oil or replace damaged components in a timely manner; Coordinate and align the limit and travel switch impact devices; Check the gear accuracy, rotor dynamic balance, bearing deflection error or damage, and whether the coupling is coaxial. Adjust or replace it if necessary.


4. Other faults

Thermocouple burned out

Possible reasons: thermocouple collided with carbon felt; Thermocouples are not sealed.

Solution: Eliminate the malfunction of the vacuum brazing furnace heater; Check the sealing ring.

Vacuum valve switch malfunction

Possible reasons: Insufficient compressed air pressure; Electromagnetic valve malfunction (vibration causing relative movement between the electromagnet and the housing).

Solution: Ensure that the air pressure is not less than 0.5MPa; Repair the solenoid valve and tighten it with rubber pads.

Mechanical pump malfunction

Possible manifestations: inability to start, reverse rotation direction, inflexible operation, low pumping efficiency, inability to achieve vacuum degree, etc.

Solution: Check the position of the motor starter switch, overload protection device, and cooling water switch; Replace the two-phase wiring in the three-phase motor; Repair according to the instruction manual; Replace with new oil. If there is no change, check other parts of the vacuum system; Eliminate oil pollution, replace the shaft end oil seal, open the damper valve to drain water.

Mechanical booster pump malfunction

Possible manifestations: inactivity, abnormal noise, inability to reach vacuum level, etc.

Solution: Check if the motor starter switch and overload protector are working; Exclude issues such as insufficient gear accuracy, poor rotor dynamic balance, bearing misalignment or damage, and different shafts in the coupling; Replace the shaft end seal and adjust the clearances between rotors, rotors and stators, and rotors and end caps.

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