2. INSTALLATION
Page 19
© 1998-2007 DH Instruments, a Fluke Company
If the molbox RFM fails to reach the main run screen:
Service may be required. Record
the sequence of operations and displays observed and contact a
DHI
Authorized Service
Provider (see Section 7.2).
molbox RFM is always powered and active when power is supplied through the rear panel
power connector. The front panel ON/OFF key controls a SOFT ON/OFF only (see Section
3.1.4
).
2.4.2
CHECK PROPER PRESSURE MEASUREMENT OPERATION
Check that the molbox RFM pressure measurements are operating properly. Proceed as
follows:
n
Connect the molbloc to the molbox RFM (see Section 2.3.3).
o
Shut off the gas supply to the molbloc and open one or both molbloc ends to atmospheric
(ambient) pressure.
p
Press
[P&T]
and observe the display of the pressure measured by the upstream and
downstream absolute RPTs. Observe the upstream and downstream
pressures
(see Section 3.4.5). These should indicate current atmospheric pressure and be in
agreement within
±
0.5 kPa (0.1 psi). If the two readings disagree by more than
±
0.5
kPa (0.1 psi), one or both RPTs may be out of calibration and service may be required.
A difference in the RPT readings could also indicate that there is some flow through the
molbloc. Check the flowpath valve or disconnect the molbloc to ensure that there is
actually no flow.
q
If the molbox RFM is equipped with the microrange option, and the option is currently
active, the bottom line left side of the display is
<mDP>
. Observe the differential
pressure value following this indication (see Section 3.4.5). It should be 0,
±
50 Pa
(0.004 psi). If the indication is different from zero by more than
±
50 Pa (0.004 psi), the
microrange differential RPT may be out of calibration and service may be required.
Again, a non-zero differential pressure could indicate an unexpected flow through the
molbloc.
r
Press
[ESCAPE]
to return to the main run screen.
2.4.3
CHECK PROPER TEMPERATURE MEASUREMENT OPERATION
Check that the molbox RFM temperature measurement is operating properly.
Proceed as follows:
n
Connect a molbloc to the molbox RFM (see Section 2.3.3).
o
From the molbox RFM main run screen, press
[P&T]
twice to arrive at the temperature
display screen. Observe the temperature readings of the two molbloc PRTs
(see Section 3.4.5). If the molbloc has been in a stable temperature environment for 30
to 60 minutes, the temperature indications should be roughly ambient temperature and
the two indications should agree within
±
0.2
°
C. If the two readings disagree more than
±
0.2
°
C, there may be a problem with the molbloc or the molbox RFM TEMPERATURE
MEASUREMENT function and service may be required.
2.4.4
LEAK CHECK
It is recommended that a new molbox RFM be leak checked at start-up to assure that no
internal leaks developed during shipping and handling. Run the molbox RFM on-board
INTERNAL LEAK CHECKING function (see Section 3.4.5).
