Ametek 241CE II Operator's Manual page 110


RUN Mode
ApplicCFGMTLo
RUN ModeApplicCFG
MTHi
5-2 | Model 241CE II Hydrocarbon Dewpoint Analyzer
To verify the analyzer is functioning properly:
1. Prepare the analyzer for functional verification:
a. Close the isolation valve on the Sample Probe or at the Sample
Inlet valve.
b. Open the Bypass Valve, if not already done, and allow the gas
pressure in the sample system and Measuring Cell to depressurize
for approximately 5 minutes.
c. Disconnect the Sample Line from the analyzer at the Filterblock
Assembly, and then remove the 1 PSIG check valve temporarily.
The check valve must be removed for this procedure and then re-
placed before reconnecting the Sample Line and resuming normal
sample operations.
2. Prevent the analyzer from cycling through the measuring cycle by
setting the mirror Low setpoint temperature (MTLo) to 0.5 degrees
below the mirror High setpoint temperature (MTHi). This will help
maintain a relatively constant temperature in the Measuring Cell and
will prevent premature condensation of the propane while setting up
the test.
3. Connect an accurate pressure gauge and a manual valve to the inlet of
the Filterblock Assembly. Locate the gauge between the filter and the
valve.
4. Next, connect an instrument grade propane tank (with a regulator
and shut-off valve) to the inlet of the manual valve.
5. With the Bypass Valve in the closed position, thoroughly flush the
Measuring Cell with propane to remove all traces of process stream
gas or air. This flushing is best accomplished by adjusting the Purge
cycle flow rate in the range of 1.0–5.0 Nl/min or 2.1–10.6 SCFH and
allowing the analyzer to purge the sample system for at least 20 min-
utes. The propane pressure is adjusted to the desired value.
 Adjust the pressure of the propane to the equal that on the Vapour
Pressure of Propane tables (Figures 5-1 and 5-2).
NOTE
The pressure on the gauge must be set at "gauge" pressure not "abso-
lute" pressure. To determine gauge pressure, subtract the barometric
pressure from the absolute pressure.