9
3.14
The Eff ects of Unwanted Vapor and Automatic Gas Ballast
Systems which contain undesirable vapors cause diffi
culty both from the standpoint of attaining
desirable ultimate pressures. A vapor is defi ned as the gaseous form of any substance which is
usually a liquid or a solid. Water, oil, and mercury vapors are three of the more common vapors
encountered in typical vacuum systems. When such vapors exist in a system, the vapors or
mixtures of gas and vapors are subject to condensation within the pump; the precipitated liquid
may thus ultimately solidify on the PTFE heads and diaphragm causing corrosion.
The 2070 pump is equipped with automatic gas ballast valve to prevent vapor condensation
in the pump. Every unit has gas ballast ON by factory setting. The gas ballast ON is indicated
by blinking RAMP UP lights. The gas ballast valve is closed when three RAMP UP lights stop
blinking and they are steady.
To disable gas ballast feature, press and hold power button until you hear two beeps, break
and three beeps. The RAMP UP light will turn ON steady.
To enable gas ballast feature, press and hold power button until you hear two beeps, break
and three beeps. The RAMP UP lights will start blinking.
3.15 Shutdown Procedures
After use, Welch recommends the pump be run for about 2 minutes disconnected from the
vacuum process. The air pumped through the mechanism will purge out water vapor or
droplets of condensate that may have formed on the inside of the pump. This purge of the
pump mechanism helps prevent build up of solute crystals inside of the pump head. Over time,
these crystals will shorten pump lifetime.
3.16 User Interface
Power ON/OFF Function – To power-on or power-off the unit when in normal power mode the
power button must be pressed for one half second and released.
Enable Power Mode feature – Power Mode feature ensures that the unit will automatically
start-up after any AC power interruption. To enable the power mode feature press and hold
the power button until two beeps are heard. Immediately release the power button. The Power
Mode LED turns on. The unit will now automatically power-up when AC power is supplied to
the unit.
Disable Power Mode feature – To disable the power mode feature press and hold the power
button until two beeps are heard. Immediately release the power button. The Power Mode LED
turns off .
