This instrument is thoroughly tested and fully calibrated at the factory and is
ready for installation.
3.2 To use the psychrometer, care must be taken to select a location for the
measurement that is representative of the area of interest. Avoid sources of heat
and cold. Especially avoid direct solar radiation.
3.3 Measurements can be made both indoor and outdoor. To prevent thermal
conduction from the hands, use the hanger provided or hang the instrument from
a stable support.
3.4 Prior to making any measurements, inspect the psychrometer for broken
thermometers, stained or soiled wicks, and free rotation of the fan. Both
thermometers should provide the same temperature measurement prior to
wetting the wick.
3.5 Upon completion of the preliminary inspection, moisten the wick. Use only clean
distilled water or soft water. Use only the syringe to moisten the wick. Never
touch the wick with fingers or hands. Human body oils will soil the wick and
cause inaccuracies in the data.
Insert the syringe into the air intake cylinder and moisten the wick completely.
Avoid excessive moistening which causes water droplets to appear at the end of
the wick. Prevent water from standing inside the wet bulb cylinder. In extremely
dry climates, moistening of the wick may require several repetitions.
If the wick is stained or old, replace it with a new clean wick. NovaLynx carries
replacement wick material, Model 225-568.
3.6 To take the actual measurement, wind the motor using the key provided.
Release the fan key and hold or support the psychrometer in a perfectly vertical
position. Watch the tops of the mercury columns. When there is no further drop
in the wet bulb column the reading can be made. Read the mercury column at an
angle of 90 degrees from the thermometer tube. A quick reading of the
thermometer is necessary because of the variable nature of the humidity. It is
suggested that the user read the tenths of degrees first and then degree units.
3.7 When taking readings with the wet bulb frozen, try to use water that is 75EF
(25EC). Melt any accumulated ice on the bulb before moistening with the warmed
water and wait 15 minutes before operating the fan. The reading will appear to
be near 32EF (0EC) and a thin thoroughly cooled coating will be seen. Due to
surface evaporation, the wet bulb temperature will gradually read below 32EF.
Read the thermometer at this point.