90 Troubleshooting and Maintenance Manual
5 CI Maintenance
To Minimize Foreline Pump Damage from Ammonia 
Air ballasting for an hour every day removes most of the ammonia from the 
pump oil. This will greatly increase the life of the pump. 
 
Procedure
1 Turn the ballast valve on the foreline pump (Figure 16) until the 1s are 
aligned. The sound of the pump will get much louder.
2 Leave the ballast valve open for one hour. You can continue to run samples 
while the pump is ballasting.
3 Close the ballast valve by aligning the 0s. Leaving the ballast valve open all 
the time will result in loss of pump oil and damage to the pump.
Only perform this procedure if the pump is at normal operating temperature. The water 
vapor in air can cause condensation of the ammonia at the ballast valve if the pump is 
cold.
Figure 16   Minimizing ammonia damage
Always purge the flow module with methane after flowing ammonia. The use of 
ammonia reagent gas also requires that the foreline pump oil be changed every 2 to 
3 months instead of the usual 6 months.