7
2.15 Discharge Provisions
Chemstar Dry intake and exhaust fi ttings are NW25 with a 3/8-18 NPT threaded ID. All
systems come with one hose barb which is supplied loose. The hose barb accepts 3/8” ID.
hose. By threading the hose barb in the exhaust port of the pump, a vent line can be attached
which allows gases and vapors pumped through the system to be piped from the work area
into a hood. V
ent lines will muffl
e noise coming from the vacuum pump.
WARNING
Never block the discharge port. If the exhaust is blocked, pressure will
build-up in the pump which can lead to the pump head bursting creating
the potential of serious injury. Remove plug from exhaust port.
WARNING
Remove plug from exhaust port before operating
Properly identify the intake and exhaust of the pump
Intake
Exhaust
2.16 Electrical Power
2.16.1 Power Source Review
Review the power source and the motor rating to be sure they agree in voltage, phase and
frequency. Serious damage may occur to the motor if it is connected to an improper voltage. All
Welch pumps must be grounded. Grounding reduces the risk of electric shock in the event of
an electrical short circuit. The plug must be plugged into an outlet properly grounded. Consult
your local electrical codes if you have doubts.
Identifi cation Symbols: Power Off / Power On
2.17 Chemical Compatibility of Vacuum Hose
Do not use fl exible PVC hose or silicone rubber hose for vacuum connections when pumping
on organic solvent vapors. Solvent such as Methylene Chloride (DCM) eff ectively leaches
out plasticizers, etc., from the PVC and silicone hose which carry over to the vacuum pump
causing contamination and vacuum mechanism failure. Using natural thick walled gum rubber
vacuum hose gives better resistance to organic solvents such as Methylene Chloride (DCM)
and protects vacuum pump against early failure.
