Edwards nEXT85 User Manual

Remedy Remove the pump from the system and test the ulmate pressure of the pump alone (refer to
Table 38 on page 86).
If inlet pressure is poor, check the pump for contaminaon and refer to Table 38 on page 86.
Leak test the pump. If the leak rate > 1x10
-7
mbar l s
-1
(1x10
-5
Pa l s
-1
), contact the supplier or
Edwards.
The pump is very noisy or there is excessive vibraon or both
Cause The pump rotaonal speed is the same as the resonant frequency of the aached system.
Remedy Change the natural frequency of the system or isolate the pump using exible bellows.
Cause The vibraon is being transmied from the rotary backing pump.
Remedy Fit exible bellows or a vibraon isolator in the backing line.
Cause The noise is irregular and geng progressively worse.
Remedy There is a defecve bearing. Contact the supplier or Edwards.
Cause The pump is making a constant high pitched noise.
Remedy The rotor is out of balance. Contact the supplier or Edwards.
No serial comms
Cause No electrical supply, loss of serial link.
Remedy Check that the electrical supply is on, that the serial link is connected and that the serial
enable line is acve.
Cause Slide switch is not in the correct posion for RS232 or RS485.
Remedy Check that the electrical supply is on, that the serial link is connected and that the serial
enable line is acve.
Le for RS485, right for RS232.
Right for parallel control and monitoring.
Cause Incorrect baud rate and node address.
Remedy Check baud rate and, if operang in mul-drop mode, the node address matches those of the
pump.
Cause Check that the red light is not on or ashing.
Remedy If LED is on, perform the checks against the red alarm LED symptoms
Fail signal or standby signal not working
Cause The serial enable line is inacve.
Remedy Must be disconnected or driven high for use of standby and fail lines.
Cause Slide switch is not in the correct posion for RS232 or RS485.
Remedy Le for RS485, right for RS232.
Right for parallel control and monitoring.
Yellow service LED is ashing a repeated sequence
B8G0-00-880A - Troubleshoong
Page 67

Edwards nEXT85 Specifications

General

Brand	Edwards
Model	nEXT85
Category	Water Pump
Language	English