2
3
2.0 OPERATION (See Figure 2-1)
Insert probe into jack at top. Turn on the switch at the left. The switch is 3-
position; the lower detent is marked “N” for normal temperature monitoring,
the middle detent is “OFF” and the upper detent is marked “P” for use of the
“Maxi Temp” Peak hold circuit. This will track temperature and hold the high-
est attained reading. The room temperature will be displayed in °C or °F as
indicated. If “L” or “Lo Bat” appears or if there is no reading, this indicates
the battery is discharged. Recharge the unit by inserting the recharger in an
appropriate power source, 50-60 Hz wall outlet and plug in the recharger jack
to the receptacle on the left side of the unit, or in the case of the 392EVX or
392VX, replace the battery. For fastest recharging time, turn POWER for the
instrument OFF. Charge for 6-7 hours.
Make measurements with sensor probe as required. Turn off switch when
measurements are complete to conserve battery life.
2.1 Meter Operation
The HEAT-Prober instrument has an accurate measuring range as stated on
the front label. The probes, however, may not be capable of this entire range
of use. Wahl probes are typically capable of -40°C to 500°C (or -40°F to
900°F).
The digital readout will show resolution to 0.1° increments from
-180.0°C to +190°C (or -290°F to 375°F). At approximately 190°C (or 375°F)
the instrument automatically ranges to one degree C or F resolution. When
returning from higher temperatures to below 190°C (or 375°F), the instru-
ment will automatically begin to read in 0.1° increments again.
2.2 Automatic Polarity
When the temperature sensed is below zero, a minus sign will automatically
show on the digital display. Absence of a sign indicates positive temperature.
2.3 Digital Display and Accuracy
The characteristic of digital readouts is a flicker in the least significant digit.
In this instrument, you can expect to see a 1-digit flicker, particularly when
reading 0.1 increments. Variations over 0.1 will be attributable to sensor tem-
perature changes.
Figure 2-1. Digital Heat
Prober Major Features