Ampro Corporation THWD-3 Manual Do Utilizador

4

The Meter displays ambient temperature when first turned on. To 
display dew point (DP) temperature, press 

 once. Press 

 again 

to switch to wet bulb (WB) temperature. Pressing 

 a third time 

returns the Meter to ambient temperature. The display indicates when 
dew point and wet bulb temperatures are selected.

Auto Power Off

By default, when the meter is powered on, it is in the auto power 
off  mode. The meter will power itself off after 30 minutes if no key 
operation is performed. To  disable the auto power off feature, press 
and hold the � button and then power on the meter, The auto 
power off symbol will disappear to indicate that auto power off is 
disabled.

Low Battery Condition

When the battery voltage is under proper operation requirement, the 
�

 symbol displays on the LCD and the battery needs to be replaced.

Wet Bulb Temperature Readings (TH-3)

Occasionally the Wet Bulb temperature is required. Use the following 
procedure and your TH-3 to obtain the wet bulb temperature.
1. Determine RH% condition with the TH-3.
2. Determine temperature (dry-bulb) with the TH-3.
3.  Locate dry bulb (DB) temperature line on the Psychrometric chart 

(vertical line across the bottom of the chart).

4.  Locate relative humidity (RH) line on the chart (curved line across 

the chart).

5. Find the intersection of the DB and RH lines on the chart.
6.  Draw a diagonal line, starting at your intersectioin point, until the 

Wet Bulb (WB) point is determined. (The wet bulb temperature line 
is at the outmost curve of the chart).

For example, locate the DB temperature of 78 °F on the Psychrometer 
chart. Locate the RH conditions of 50% RH on the chart. Draw a 
diagonal line up to the 65 °F WB point.