Digital Temperature, Humidity, Dew Point Monitor 

Operation Manual 
-

Specifications 

Range: 

Temf)erature-

-22 to + 1 22°F, (-30 to +50°C) 

Humiditya to 950fo RH (non-condensing) 

Dew Point-

-22 to + 1 22°F, (-30 to +50°C) 

Resolution: 

1 Ofo RH, 1 o 

Accuracy: 

Temperature- ± 1.8°F (± 1.0°C) 

Humidity-

±20fo RR from 0 to 60%, ±30fo RH 

tram 61 to 950fo at+73°F 

Humidity Sensor: 

Thin firm capacitor 

Dew Point Accuracy: ±3.6°F (±2°C) 

Instrument Anatomy 

Wand 

Temperature Sensor: 

Tnermistor 

Sample Rate: 

Approx. 1 per second 

Average Response Time: 

5 seconds to move 600fo of full 

scale in air moving I 5'/second 

Ambient Operating Conditions: 

+32 to+ T22°F (Ol:o +50°C) 0 to 900fo RH (non-condensing) 

Power Supply: One 9V alkaline battery. Battery life approx. 80nours . 

Dimensions: 6.25" x 2.5" x 1.9" 

( 160mm x 65mm x 45mm) 

Probe Dimensions: .92" diameter (23mmj. 5.9" 

(149mm) long on a 6 (1 8 m) cord 

Weight: I I oz. (.31 kg) 

Sanda ---+!HI 

Em bout 

Lesekopf 

Min/Max Key 

Baton de min./max 

Touche Min/Max 

Taste Min/ Max 

Hold Baton Key de retencion --l§~~~~~ Touche hold 

Taste Hold 

Battery Compartment _j Compartimiento de Ia pila 

Compartiment a' pile 

Batteriefach 

a 

r1! If K •y 

Baton de encendid y c~p. qc~do 

Tau h n/ ff 

Ein-/Au 

Rh/Dew Pt. Key 

Baton de humedad relativdlpunt o cle rocio 

Touche Rh/Dew 

Taste Rh/Dew 

•c;•F Key 

Baton de •c;•F 

Touche •c;•F 

Taste •c;•F 

Strain Relief 

Alivio de tension 

Soulagement de Traction 

Zugentlastung 

5' Long Cord (I ~ Ill! 

Cordon de 154 c "' ('•' 

Gordon de 1 54 em dl' '""!J 

Spira/schnur, I ' 4 c r" 

Operating Instructions 

I . On/Off 

Press to turn unit on or off. 

2. Set Celsius or Fahrenheit Mode 

Press "°CfOF" key to choose Celsius 

or Fahrenheit. 

3. Set Humidity or Dew Point Mode 

Press "Rh/Dew" key to choose Humidity or Dew Point. 

Note: Dew Points below freezing should be converted to frost points. 

• 

4. Set Wand Position 

, ,oF 

• • 2YdP 

• 

Slide wand upward to first notch or remove wand completely from 

cradle. Avoid breathing on or touching wand end as this could distort 

readings. 

5. Update Indicator 

Karet moves up or down each time the unit 

takes a new reading, approximately once every 

second. 

6. Hold 

Press this key to lock in current reading. The 

"Hold" symbol in the display w ill light up, 

indicating that the instrument is in the "Hold" 

mode. To resume reading, press the "Hold" 

key again. 

Ciil!i] 

lBOF • 

22rh 

a 
-

Operating Instructions, Ctd. 

7. Automatic Shutoff This instrument will 

automatically shut down after "" 34 minutes if 

no keys are pressed. 

8. Automatic Shutoff Override 

You may override the automatic shutoff feature at startup by pressing down the "Hold" 

key. and the "On" key at the same time. The 

letter 'T' will light up in the display, indicating 

that the shutoff timer is in the override mode. 

T 

9. Minimum/Maximum 

Press "Min/Max" once and the minimum values will be displayed for approximately 7 sec 

onds. 

Press "Min/Max" again during this time and 

the r:naximum values will be displayed for 7 

seconds. 

Press "Min/Max" a third time during this period and the unit will return to normal opera 

tion. 

Unit will always return to normal operation 

after 7 seconds if no keys are pressed. 

Note: Turning the unit off resets the minimum 

and maximum values . 

a 

Minimum Display 

Maximum Display 

Battery Installation 

Battery should be replaced as soon as possible 

after low battery indication to maintain rated 

accuracy of unit 

Calibration 

Your instrument was carefully tested 

and calibrated before being 

shipped from the factory. 

Additional calibration is not 

required. However. should calibration be desired in the future. follow 

these procedures: 

1 . Identify a standard that is more 

accurate than this unit Factory 

supplied calibration salts or electronic instruments recently calibrated at a certified lab are recommended. Sling psychronmeters and instruments using 

mechanical sensing elements 

(human hair. wood 

elements. etc.) are NOT 

recommended. These instruments can be subject to great 

inaccuracies due to the nature of 

mechanical measurement. 

2. Place the probe of the unit into 

the calibration salt capsule or 

into a controlled environmental 

chamber and allow for complete 

stabilization. For best results. 

calibrate the unit at levels typically monitored during normal 

a 

operation. Calibration in an 

open room without the salt capsule or a chamber is not recommended as temperature and 

humidity can vary greatly within 

a very small area. 

3. To activate the calibration mode. 

turn the unit off. Now press the 

"On/Off' key and the "C/F" key at 

the same time. A small "J" will 

appear in the display to indicate 

you are in the calibration mode. 

Step 3: Activating Calibration 

Mode 
-

Calibration, Ctd. 

4. To lower the humidity or dew 

point reading, press the 

"RH/Dew" key. To raise the 

humidity or dew point reading, 

press the "Min/Max" key. 

5. To lower the temperature reading, press the "Hold" key. To 

raise the temperature reading, 

press the "

0 C/°F" key. 

6. When calibration is complete, 

simply turn the unit off to exit 

the calibration mode. 

Temperature 

Down 

Notes: This procedure allows for a 

I 0 digit change in readings. If 

greater change is required, there is 

either a need for factory seNice or 

the standard being used is inaccurate. 

For most accurate full scale calibration, factory seNice is recommended. 

Temperature Up 

Keypad Functions in Calibration Mode 

a 

Troubleshooting 

Problem 

Inaccurate Reading 

Display won't change. 

"E" appears in display 

Display fading 

"Err" appears 

LO BAT symbol appears 

Probe exposed to environments exceeding 

95% RH for extended period 

Parts List 

Solution 

Allow indicator to stabilize. 

Check battery power ILO BAT). 

Incorrect reference being used. 

Out of calibration. 

Check manual for calibration procedure. 

Unit in "HOLD" mode (press HOLD again) or is 

locked up (Turn indicator OFF, remove battery, 

re-install battery & turn ON) 

Component failure. Contact factory. 

Weak battery. Change battery. 

Bad cord connection or out of range. 

Pull rubber boots off wand and unit. check 

for proper connections. 

Check to see that environment measured is 

within operating range of unit---<:heck 

manual p.2- ambient operating conditions. 

Replace battery 

Probe should be dried out under normal 

ambient conditions- Time required varies 

on temperature. RH & air flow 

Some parts are easily replaced on site. Please refer to table below. 

Description Part# 

Accessories 

Calibration Kit (11 % and 75%1 AB34 

NIST Traceable Certificate, 3- oint* N3TH5 

NIST Traceable Certificate, ULTIMA* N4TH5 

*Must be requested when ordering. add one weeK to delivery time. 

a 
Factory Service and Returns 

We recommend that damaged 

instruments be returned to our 

factory for complete repair. Before 

returning any instrument or 

package, please call for a 

Return Authorization 

(RAJ Number. 

The Dickson Warranty 

Dickson warrants that the TH550 

will be free from defects in material 

and workmanship for a period of 

twelve months after delivery. In the 

event of a claim under this warranty, the product or part must be 

returned to the factory for repair or 

replacement (shipping prepaid) 

with a Return Authorization 

Number (See "Factory Service & 

Returns information above). It will 

be repaired or replaced at Dickson's 

option without charge. 

When calling, please have the 

following information available: 

I . P.O. number for out-ofwarranty units. 

2. Serial number of unit. 

3. Model number of unit. 

4. The problem you're 

experiencing with unit. 

The foregoing warranty and 

remedy are exclusive and in lieu 

of all other warranties either 

expressed or implied. 

Dickson shall not be liable for consequential or incidental damages 

resulting from failure or malfunction 

of its products. Products not 

manufactured by Dickson 

are excluded from this 

warranty. 

Dickson manufactures a complete line of temperature, humidity, air quality 

& pressure instruments. Send or call for a free catalog of Dickson products. 

Toll Free 1-800-323-2448 

DICKSON 

The Leader In Recorders 

930 South Westwood Avenue • Addison. IL 60 I 0 I 

Telephone 630-543-3747• Fax 630-543-0498 

MAN02 Revised 12/96 

II 

Especificaciones 

lntervalos: 

• Temperatura-

-300C a 50°(. (-22°F a I22°F) 

• Humedad- 0 al 95% (sin con 

densaci6n) 

• Punto de rocio-

-300C a 50°(. (-22°F a I22°F) 

• Resolucion: 

I o/o de humedad relativa, I o 

• Precision de laTemperatura: 

±1°( (±1,8°F) 

• Precision de Ia Humedad: 

2% from 0 to 60%, ±3% from 61 

to 95% RH 23°( (73°F) 

• Precision del Punto de rocio: 

2°( (3,6°F) 

• Detector de humedad: 

tipo capacitancia 

• Detector de temperatura: 

termistor 

• Muestras: aproximadamente I 

II 

par segundo 

• Fuente de alimentacion: una 

pila alcalina de 9 voltios. La 

duraci6n de Ia pila es de unas 

80 horas. 

• lntervalo de operacion 

ambiental (cuerpoJ: 

ooc a 50°C {32°F a I22°F) 

Oa 90% HR 

• Tamano: I 59 x I 59 x 48 mm 

• Probe Dimensions: 

92" diameter (23mm), 5, 9" 

( 149mm) long on a 6' ( 183cm) 

cord 

• Peso: 0,31 Kg 

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