3. Close the gas-ballast control.
4. Open the vacuum system isolaon-valve and pump down to ulmate vacuum.
5.5 To pump condensable vapours
Use gas-ballast (open the gas-ballast control) when there is a high proporon of
condensable vapours in the process gases:
1. Close the vacuum system isolaon-valve.
2.
Turn the gas-ballast control an-clockwise to fully open and operate the pump for
30 minutes to warm the oil, this will help to prevent vapour condensaon in the
pump.
3.
Open the vacuum system isolaon-valve and connue to operate the pump with
the gas-ballast control open.
Aer pumping condensible vapours, decontaminate the oil (if necessary), use the
procedure in To decontaminate the oil on page 25.
5.6 To decontaminate the oil
The oil in the pump should be clear. If the oil is cloudy or discoloured, it is contaminated
with process vapours.
1. Look at the condion of the oil in the oil sight-glass (Figure: General view of the
pump on page 11). If the oil is cloudy or discoloured, connue with the procedure
at step 2 below.
2. Close the vacuum system isolaon-valve.
3. Turn the gas-ballast control fully an-clockwise.
4. Operate the pump unl the oil is clear.
5.7 Unaended operaon
The pump is designed for unaended operaon under the normal operang condions
specied in Operang and storage condions on page 12. However, we recommend you
to checking the pump at a regular interval of not more than 14 days, check the pump
more frequently if pumping high volumes of gas or if operang the pump with the gas-
ballast control open.
The motor is protected by an overload device which isolates the pump from the
electrical supply when crical temperature or current levels are exceeded. The overload
device resets automacally when the motor has cooled. When checking the pump, make
sure that the pump is not going through a repeve cycle of thermal overload failures
and automac resets. If necessary, reduce the thermal load from the pumped gases, to
prevent overheang of the pump.
5.8 Shut-down
Note:
If the gas-ballast control is open and the motor is switched o for any reason, the pump
drive sha may rotate in the reverse direcon, causing a system pressure rise. To prevent
Page 25
A37132880_F - Operaon
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