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Reference Manual
00809-0700-4530, Rev AA
Section 5: Troubleshooting Procedures
September 2013
Troubleshooting procedures
5.5.5 Incorrect static vapor compensation
Specific high-temperature and high-pressure applications, like those with saturated steam
vapors, require that a compensated value be entered for the vapor dielectric constant. This
compensation is fixed and will only adjust the level reading at a specific condition. Normally, this
means that the transmitter will show a correct level reading during operation, but not during
startup and shutdown. Alternatively, if no correction is entered, the level reading will be correct
during shutdown, but not during startup and operation (see Table 5- 3 and Table 5 -4 ).
Table 5-3. Properties of water and saturated steam
Table 5-4. Level reading errors during shutdown, with fixed saturated water steam
correction activated
NOTE:
When performing verification at ambient pressure and temperature conditions, always set
vapor dielectric to 1. Otherwise level reading will be incorrect.
To set the Vapor Dielectric constant in RRM:
RRM > Tank > Environment
Temp.
°F/°C
Pressure
psia/bar
DK of
liquid
DK of
vapor
Error in
distance %
100/38 1/0.1 73.95 1.001 0.0
200/93 14/1 57.26 1.005 0.2
300/149 72/5 44.26 1.022 1.1
400/204 247/17 34.00 1.069 3.4
500/260 681/47 25.58 1.180 8.6
600/316 1543/106 18.04 1.461 20.9
618/325 1740/120 16.7 1.55 24.5
649/343 2176/150 14.34 1.8 34.2
676/358 2611/180 11.86 2.19 48
691/366 2900/200 9.92 2.67 63.4
699/370 3046/210 8.9 3.12 76.6
702/372 3118/215 Above critical point, distinct liquid and gas
phases do not exist.
Entered
Vapor DC
Error in reading, when actual Vapor DC is 1
(corresponding to water at room
temperature)
Offset in reading,
if Vapor DC is
configured
correctly
Surface at 15 in (380
mm) from flange
Surface at 30 in. (760
mm) from flange
1.001 0 in. (0 mm) 0 in. (0 mm) 0 in. (0 mm)
1.022 0.2 in. (4 mm) 0.3 in. (8 mm) 0 in. (0 mm)
1.180 1.3 in. (33 mm) 2.6 in. (65 mm) 0 in. (0 mm)