Edwards nEXT 55, Instruction Manual

Page: 72 / 116

Refer to Fault finding on page 90 if:
▪ LEDs do not illuminate
▪ Red or yellow LEDs flash in a repeated sequence
▪ Red LED is illuminated.
6.2 Vent options, vent valve connection and control
Note:
If manually venting the pump when it is at full rotational speed and the rate of increase
in pressure is too high, the pump life can decrease. When using the manual vent valve,
we recommend you to limit the vent or open the vent valve only after the pump speed
decreases to 50% of the full rotational speed. Do not vent from the backing line to
prevent contamination. If venting into the vacuum system and using an oil sealed rotary
backing pump, select a point upstream of the pump to prevent oil back
‑
streaming from
the backing line. The vent rate must be as per the limits given in Vent gas specification
and vent control data on page 22. Refer to Table: Vent restrictor orifice diameter if
venting the vacuum system chamber for the vent restrictor orifice to be installed on the
vent valve.
To keep the cleanliness of the vacuum system, we recommend you to vent the pump (or
vacuum system) when setting the pump to off.
6.2.1 Manual vent valve
We recommend you to open the manual vent valve only after the pump speed
decreases to 50% of the full rotational speed.
A manual vent valve is supplied with the pump. Precise controlling of the rate of
increase in pressure is not possible with the manual vent valve. Do not open the manual
vent valve too quickly.
6.2.2 TAV5 solenoid vent valve
The TAV5 solenoid valves is available as an accessory. The TAV5 solenoid valves comes as
pre-wired with an auxiliary connector installed or as a bare-wire option.
'Normally Closed' and 'Normally Open' valves are available. Refer to
Accessories on page
105.
Venting can be done by one of the methods that follow:
▪ Use the TAV5 solenoid vent valve in the manual vent valve position.
▪ Use the TAV5 solenoid vent valve connected to a convenient flange on the vacuum
system.
▪ Use an alternative vent valve, with correct restriction, connected to the vacuum
system.
When using the TAV5 vent valve, the pump can be hard vented only when it is at full
speed if the vacuum system has a volume of 5 litres or more.
If the volume of the vacuum system is less than 5 litres, install a vent restrictor and vent
the pump when it is at full speed or use the controlled venting option. Refer to Table:
Vent restrictor orifice diameter if venting the vacuum system chamber for applicable
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B8G000880_E - Operation