A705-40-880 Issue B
Page 68 © Edwards Limited 2011. All rights reserved.
Edwards and the Edwards logo are trademarks of Edwards Limited.
Maintenance
5.17 Fault finding
Table 17 - Fault finding
Symptom Check Action
The pump-motor starts but the pump
does not operate.
Has the torque limiter decoupled
the pump-motor from the pump?
Recouple the pump-motor to the
pump: refer to Section 4.4.
The pump suddenly stops or the
torque limiter continually decouples
the pump-motor from the pump
when reset. The pump-motor may be
tripping due to excessive electrical
current consumption.
Is there a hydraulic lock in the
pump?
Switch off and drain the fluid from the
pump. If necessary, turn the pump by
hand (refer to Step 7 of
Section 5.11.3), then recouple the
pump-motor to the pump
(refer to Section 4.4).
Has the pump seized due to
deposits?
Switch off and then flush the pump
(refer to Section 5.10), then recouple
the pump-motor to the pump
(refer to Section 4.4).
The pump stops but the torque
limiter does not decouple the pump-
motor from the pump.
Has the thermal snap-switch (if
fitted) operated to stop the pump
because the pump is operating at
too high a temperature?
Check that the thermal snap-switch is
correctly set for the required operating
temperature. If necessary, adjust the
thermal snap-switch (refer to
Section 3.12.1).
Has your ATEX control circuit
operated to stop the pump
because the pump is operating at
too high a temperature?
Check that the temperature
transmitter is correctly connected to
your control circuit, and that the
control circuit is correctly configured:
refer to the ATEX System instruction
manual.
Is the TCV incorrectly set? Check that the TCV is set to the
required operating temperature. If
necessary, adjust the TCV
(refer to Section 3.12.4).
Is the coolant level too low? Check that the coolant level in the
pump is correct. If necessary, add
coolant (refer to Section 5.10).
Is the heat exchanger blocked? Check that there is a flow of cooling-
water through the heat exchanger:
look at the cooling-water flow
indicator. If your cooling-water supply
is on and is at the correct pressure, the
water filter or the heat exchanger may
be blocked: clean the cooling system
(refer to Section 5.12).
Has the pump seized because the
thermal snap-switch (if fitted) is
faulty?
Check the temperature at which the
thermal snap-switch operates. If the
temperature of the pump-body is
> 20 °C above the thermal snap-switch
setting, the thermal snap-switch is
faulty and you must replace it: contact
your supplier or Edwards for advice.
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