Edwards nEXT400 User Manual

Fault The pump does not rotate aer a serial st
art command is sent
Cause Check if the pump returns a reply to the start command.
Remedy If there is no reply, do the checks given in No serial comms on pag
e 84 or do the
checks given in The pump does not rotate aer a parallel start command is sent on
page 82.
Fault The pump does not respond in mul- drop mode
Cause The mul-drop is disabled.
Remedy Make sure the pump has a mul-drop address. Make sure that the commands are
sent using the mul‑drop protocol.
Fault The green Normal LED does not light or the pump does not rotate at full speed or
the pump fails while in oper
aon
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 too hot when in oper
aon.
R
emedy
▪ Increase the cooling to the pump. Change from air cooling to water cooling
(refer to Technical data on page 18 for maximum inlet pressure and cooling
requirements).
▪ Increase cooling water ow 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 supplier or us.
Fault Ulmate pressure cannot be reached
Cause Pr
essure 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 not sucien
t (bec
ause of poor conductance between the pump
and the gauge or the chamber is too large).
Remedy Increase the conductance or decrease the volume.
Cause Inlet pressure is more than 0.5 mbar (50 Pa).
Remedy If the interstage inlet pressure is too high, the inlet pressure at the turbomolecular
inlet is incr
eased. Make sure that the interstage inlet pressure is less than 0.5 mbar
(50 Pa).
Cause
The backing pressure is more than 10 mbar (1x10
3
P
a).
Remedy The backing pressure can be too high. Check for backing pipeline leaks. If the
throughput is high, a larger backing pump can be necessary.
04/2022 - ©Edwards Limited
Page 83B80000880_G
B80000880_G - Fault nding

Edwards nEXT400 Specifications

General

Brand	Edwards
Model	nEXT400
Category	Water Pump
Language	English