1102   Error: Vacuum (BK) time out. Vacuum too high to switch on Ion gauge (AN).

The Ion gauge cannot be turned ON because the vacuum pressure (IF/BK) is not below the limit within the prescribed time (When the instrument is changing from Shutdown mode to Standby mode).

Check the vacuum pressure (IF/BK) for the following possible issues.

• The vent valve is not closed or the seal is incomplete.
• The cover of the vacuum chamber is not closed or the seal is incomplete.
• The power of the foreline pump is not connected or the breaker is OFF.
• The foreline pump oil level is low or the oil is dirty.
• There is a leak in the gate valve.
• The vacuum tubing has failed (the tubing is off, or a leak is caused by an incomplete seal such as a pin hole or a defective O-ring).
• There is a fault in the Pirani gauge (IF/BK) or the Connection PCA.
• There is a leak in the backing line, between turbo pump backing port to foreline pump inlet.