Unstable vacuum readings can affect furnace process control and product quality.
Possible causes include chamber leakage, outgassing, pump problems, valve leakage, and inaccurate pressure measurement.
A systematic troubleshooting sequence helps avoid replacing instruments unnecessarily.
1. Check the Process Trend
Review the pressure trend during evacuation, holding, heating, and gas filling.
Determine whether the pressure is continuously rising, fluctuating, or failing to reach the target value.
The timing of the problem can help narrow down the cause.
2. Check the Vacuum Gauge
Inspect the gauge power supply, cable, signal output, sensor condition, and installation.
If possible, compare the reading with an independent calibrated gauge suitable for the same pressure range.
Remember that different vacuum gauge technologies may respond differently to gas composition.
3. Check the Vacuum Pump and Valves
Inspect pump operating conditions, isolation valves, vent valves, and pipeline connections.
A valve that does not close completely can cause pressure instability even when the chamber itself is tight.
4. Perform an Approved Leak Test
If the measurement system is verified and pressure behavior still indicates a leak, conduct a suitable leak test.
Use the furnace manufacturer’s approved procedure and appropriate leak detection equipment.
5. Check Outgassing and Process Conditions
Moisture, surface contamination, hot materials, and process residues can release gas into the chamber.
Heating may increase outgassing and cause pressure to rise even when there is no external leak.
Conclusion
Do not automatically choose between leak checking and gauge replacement.
First verify the pressure measurement, then inspect the pump and valves, and finally investigate leakage and outgassing according to the observed pressure trend.
Scan the QR code to receive more detailed information.
