E-DWT-10000-AF OPERATION AND MAINTENANCE MANUAL
© 2008 DH Instruments, a Fluke Company
Page 20
The E-DWT Lo Q-RPT shut off valve (8) must always be in the closed position (knob fully CW) when
operating at pressure greater than 1 000 psi (7 MPa).
The
CAUTION LO Q-RPT ACTIVE
LED
(10) is used to indicate that the Lo Q-RPT is active and provide
an alert when the Lo Q-RPT is active but a Hi Q-RPT range is selected on the RPM4-E-DWT.
The
CAUTION LO Q-RPT ACTIVE
LED (10) is driven by the value of pressure currently measured by the
Lo Q-RPT , it is not driven by the valve position as there is no sensing of the valve position.
The
CAUTION LO Q-RPT ACTIVE
LED (10) has three possible conditions:
•
LED is OFF: The Lo Q-RPT is NOT active. The Lo Q-RPT is considered active when it measures a
pressure greater than about 100 psig (700 kPa).
•
LED ON continuously: The Lo Q-RPT IS active (exposed to pressure greater than 100 psi) and the
Lo Q-RPT is selected on the RPM4-E-DWT. The LED is lit as a reminder that the Lo Q-RPT is active
and pressure over its maximum working pressure of 1 000 psi (7 MPa) should not be applied.
•
LED is flashing ON/OFF accompanied by high frequency beeps and <!!LO Q-RPT ACTIVE!!>
displayed by RPM4-E-DWT: Lo Q-RPT IS active and the Hi Q-RPT is selected on RPM4-E-DWT.
The Lo Q-RPT should NOT be exposed to pressure when the Hi Q-RPT is selected. Exposing the Lo
Q-RPT to pressures for which the Hi Q-RPT is normally used, will overpressure and damage the Lo
Q-RPT Vent pressure from the RPM4-E-DWT and shut off the Lo Q-RPT with the Lo Q-RPT shut off
valve before continuing to use the Hi Q-RPT.
If the Hi Q-RPT is selected with the Lo Q-RPT active, RPM4-E-DWT goes into an alarm condition to avoid
accidental overpressure of the Lo Q-RPT while using a Hi Q-RPT. The pressure on the Lo Q-RPT must be reduced
to less than 100 psig (700 kPa) so that the CAUTION LO Q-RPT ACTIVE LED is OFF before shutting the Lo
Q-RPT shut off valve and selecting the Hi Q-RPT.
The E-DWT pressure relief valve (Figure 10, Ref 7) is set to open at 150% of the RPM4-E-DWT Lo
Q-RPT maximum range. When the pressure applied to the Lo Q-RPT reaches approximately 1 500 psi
(10 MPa), the pressure relief valve will open exhausting oil to the reservoir and reducing pressure. Prior
to opening the pressure relief valve, the RPM4-E-DWT will have gone into an overpressure condition (see
Section 3.8.4.1). If an overpressure condition occurs, reduce pressure as soon as possible. The
pressure relief valve will reseat automatically and close when pressure is reduced.
Do NOT overpressure the Lo Q-RPT. The Lo Q-RPT may be damaged beyond repair by pressure greater than
1 300 psi (9 MPa). Q-RPT damage from overpressure is logged in user and factory maintenance pages and is not
covered by the product warranty. The E-DWT pressure relief valve should only be considered a last resort means of
protecting the Lo Q-RPT. Following proper operating procedures, the Lo Q-RPT should never be over pressured.
