INFICON QS5 - Manual (Page 8)

6
QS5 Operating Manual
IT IS IMPORTANT THAT THE PUMP HAS REACHED ITS NORMAL
OPERATIONING TEMPERATURE (50°C-70°C / 122°F-158°F) BEFORE ANY
CONDENSABLE VAPORS ARE PUMPED. FAILURE TO DO THIS MAY
CONTAMINATE THE OIL AND DAMAGE THE PUMP.
10
The QS5 is now ready to evacuate air conditioning and refrigeration
systems.
UNDER NO CIRCUMSTANCES SHOULD THE FITTINGS ON THE
VACUUM PUMP BE USED FOR REFRIGERANT TRANSFER, AS DAMAGE
WILL OCCUR TO THE VALVE.
6.0 Using the Gas Ballast
The gas ballast valve allows a controlled amount of air to enter the
compression chamber, diluting any water vapor present, then exhausts it out
of the compression chamber before it condenses and accumulates in oil
reservoir.
The gas ballast valve can be opened or closed at any time during pump
operation. It is also helpful to open it in the following situations:
 During start-up, it will help the pump reach its normal operating
temperature sooner, as a cold pump will more easily condense vapor.
 During the evacuation process, it will minimize the effect of vapor
condensing within the pump, but it may slightly reduce ultimate vacuum.
If deep ultimate vacuum is required, the Gas Ballast may be closed later
in the evacuation process.
 During shut down, it will allow the pump to purge condensable vapors.
Gas Ballast valve, when closed, must only be finger-tight. Otherwise,
the valve seat may be damaged.
7.0 Shut-down Procedure
1
CLOSE the manifold valve between the QS5 and the system.
2
OPEN Gas Ballast valve for a few minutes before shut down. This allows
the pump to purge condensable vapors.
3
Turn power switch OFF.
4
If necessary, drain oil while the pump is warm.