The Pump Does Not Respond In Multi- Drop Mode; The Green Normal Led Does Not Light Or The Pump Is Not Rotating At Full Speed Or The Pump Fails Whilst Running; Ultimate Pressure Cannot Be Reached - Edwards nEXT730D Instruction Manual

Fault

The pump does not respond in multi- drop mode

Cause The multi-drop is disabled.
Remedy Make sure the pump has a multi-drop address and that commands are sent using
the multi‑drop protocol.
Fault The green Normal LED does not light or the pump is not rotating at full speed or
the pump fails whilst running
Cause The inlet pressure is too high.
Remedy Reduce the pumping load or check for a gross leak into the system.
Cause The pump is running too hot.
▪ Increase the cooling to the pump. Change from air cooling to water cooling
Remedy
(refer to for maximum inlet pressure and cooling requirements).
▪ Increase cooling water flow or decrease the water temperature or do both.
▪ Check that external heat sources (such as system bakeout heaters) are not
excessive.
Cause The rotor does not rotate freely.
Remedy The pump bearings may be damaged. Contact the supplier or Edwards.
Fault

Ultimate pressure cannot be reached

Cause Pressure is limited by water vapour.
Remedy Bake the system and pump.
Cause The vacuum gauges are contaminated.
Remedy Clean or replace the vacuum gauges.
Cause Pumping speed is insufficient due to poor conductance between the pump and
the gauge or
the chamber is too large.
Remedy Increase the conductance or reduce the volume.
Cause Inlet pressure is > 0.5 mbar (50 Pa).
Remedy If the interstage inlet pressure is too high, inlet pressure at the turbomolecular inlet
is increased; ensure that the interstage inlet pressure is < 0.5 mbar (50 Pa).
Cause
The backing pressure is > 10 mbar (1x10
Remedy The backing pressure may be too high. Check for backing pipeline leaks. If the
throughput is high, a larger backing pump may be required.
Cause The high vacuum area of the system is contaminated.
Remedy Clean the high vacuum system.
Cause Check the rest of the system for leaks and contamination.
Remedy If found, repair the leaks and clean the contamination.
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Pa).
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