1103   Error: Vacuum pressure (BK) increased above turbo ON limit.

The turbomolecular pump cannot be turned ON because the vacuum pressure (IF/BK) exceeds the limit or the turbomolecular pump was turned OFF because the vacuum pressure increased abnormally (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.