Surface Area Display Not Clearing To Zero; Degas Temperature Fails To Function Properly - Micromeritics FlowSorb III 2305 Operator's Manual

Troubleshooting

Surface Area Display Not Clearing to Zero

Temperature changes and aging of components may cause the surface area dis-
play to register a number slightly different from zero when it is cleared. To cor-
rect this condition:
1. Remove the instrument rear panel, being careful not to contact any of the
electrical leads in the lower portion of the instrument.
Proceed with caution; electrical power must be on for this procedure. Touch-
ing a lead wire could cause electrical shock.
2. Locate the circuit board mounted beneath the top panel of the instrument
and immediately above the display.
3. On the circuit board, locate R2 (the closest potentiometer to the green test
point) located at the end of the circuit board and just above the edge of the
display meter.
4. Hold down the display Reset button and using a small, flat-head screw-
driver, adjust the potentiometer until the display registers zero.

Degas Temperature Fails to Function Properly

A flashing temperature display indicates that either the thermocouple is discon-
nected or that a temperature of 400
couple is plugged into its receptacle. If the thermocouple is plugged in, unplug
the thermocouple and examine its leads for broken connections. If the thermocou-
ple is intact, check to see if a degas temperature of 350
specified; if so, specify a lower temperature. Circuitry inside the instrument pro-
tects the operator, the sample tubes, and the heating mantles by limiting the tem-
perature to 400
The thermal characteristics of the heating mantles prevent temperature regulation
to a precision better than approximately ± 10
with the temperature oscillating about the chosen temperature by several degrees,
the initial overshoot will be the largest. The actual temperature at the sample will
be somewhat lower than initially indicated and will vary less due to the moderat-
ing effects of the glass wall of the sample tube and the flowing stream of gas.
The temperature control circuitry has been designed to require about 20 minutes to
reach the desired setting regardless of how high the setting may be. This controlled
ramping of temperature is intended to minimize destructive changes in the sample,
especially those due to the boiling off of moisture. Faster heating may be achieved by
setting to a much higher temperature than desired, and then reducing the setting to
the desired temperature when that temperature is reached.
4-4
o
C has been reached. Ensure that the thermo-
o
C regardless of the setting chosen by the operator.
o
C or higher has been
o
C. Normal operation is cylical
FlowSorb III
Sep 2011