A708-01-880 Issue E
Page 32 © Edwards Limited 2013. All rights reserved.
Edwards and the Edwards logo are trademarks of Edwards Limited.
Installation
3.7 Connect the oil pressure sensors (CDX pumps only)
Ensure to route the pressure sensor cables away from hot surfaces of the pump or other equipment. If not, the
cable may be damaged.
The pressure sensors measure the oil pressure in the supply pipes. Connect the output of the sensors to a suitable
control circuit to shut down the pump when either of the sensors detects a loss of pressure.
Set the control circuit trip setpoint (that is, the pressure setpoint at which the control circuit will shut down the
pump) to 0.3 barg (5 psig).
Note: Incorporate a suitable time delay in the signal in the control circuit to allow the pump to start, as initially
there is low oil pressure until the pump attains full rotational speed. The amount of delay will depend on
the ramp-up time set on the VFD.
3.8 Connect the thermal snap-switches (IDX pumps only)
Ensure that the thermal snap-switch cable is routed away from hot surfaces of the pump or other equipment. If
not, the cable may be damaged.
If required, connect the output of the warning thermal snap-switch to the control equipment to provide an indication
that the pump is too hot.
Connect the output of the shut-down thermal snap-switch so that the pump is automatically switched off when it is
too hot.
The thermal snap-switches will reset (that is, close again) when the pump cools down to a preset temperature (see
Section 2.8). Edwards recommends that the control equipment incorporates a manual reset device so that the pump
does not automatically switch on after it cools down.
Use the following procedure to connect to the thermal snap-switches. If connecting to the thermal snap-switches as
described in this Section, the outputs from the thermal snap-switches will be normally closed and will open when the
pump is too hot.
Connect the oil pressure sensors to a suitable control circuit to shut down the pump when the oil
pressure drops. If not, the system will not be ATEX compliant (if applicable), damage to the pump
can result, and there may be a risk of explosion or fire.
Connect the shut-down thermal snap-switch so that the pump stops when the thermal snap-switch
opens. This must be independent of the oil pressure switches so that if the thermal snap switch or
either of the oil pressure switches open, the pump will be shut down. If not, a fire may result.
Incorporate a manual reset device in the control equipment. If not (and a fault which causes the
shut-down thermal snap-switch to open is not corrected), the pump will automatically switch on
again when it cools down. If maintenance or fault finding has been started on the pump, there will
then be a risk of injury to people.
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