Prostat PHT-771 User manual

User Manual
PHT-771
DIGITAL PSYCHROMETER


  Page
I. General Operaon 4
II. Display Descripon 5
III. Taking Measurements 5
IV. Wet Bulb and Dew Point measurements (no Second Sensor) 6
VWet Bulb and Dew Point measurements (with Second Sensor) 6
VI. Minimum (MIN) Maximum (MAX) Funcon 6
VII. Data Hold Funcon 7
VIII. Automac Power O Feature 7
IX. Lo Baery Indicator 8
X. Error Messages 8
XI. Maintenance 8
General Specicaons 10

Copyright © 2011 by Prostat® Corporaon. All rights reserved. Printed in the United States of America. No part of this
manual may be used or reproduced in any manner whatsoever without wrien permission. For informaon contact
Prostat Corporaon, 1072 Tower Lane, Bensenville, IL 60106 USA
Prostat is the registered trademark of Prostat® Corporaon

 
Meter Descripon
1. Humidity Sensor & Air Temperature Sensor
2. Triple LCD Display
3. ON/OFF buon
4. T1-T2/Dew Point/T1 buon
5. °F/°C select
6. MIN/MAX/RESET buon
7. T2-DP/Wet Bulb/T2 buon
8. HOLD buon
9. T2 Probe Jack
A. Gently turn the sensor cover towards the “Open” posion unl it stops. (Do not try to remove the
cover)
B. Turn the PHT-771 on by pressing the Red ON/OFF Buon.
1. Press and hold the ON/OFF Buon approximately one second. Unit will perform a short self-
test when turned on. The unit is ready to funcon when the humidity and temperature is
indicated, allow 60 - 80 seconds for the unit to take a reading.
2. Do not press hard.
C. Press and hold the ° C/ ° F key for approximately 2 seconds to convert the reading to the desired
Cengrade/Fahrenheit scale.
1. Temperature, Relave Humidity and Wet Bulb will display simultaneously, or Relave Humidity,
Dew Point and Wet Bulb will display simultaneously by pressing .
D. Condensaon will not aect the meters accuracy.
E. Press the ON/OFF buon briey to turn the unit OFF
F. Gently turn the sensor cover towards the “Close” posion unl it stops when the unit is not in use
or for storing unit.
4Rev. C / October 2011
PHT-771 Digital Psychrometer

 
1. Relave Humidity %
2. T1
3. T1-T2
4. Dew Point
5. Wet Bulb
6. T2-Dew Point
7. °C/°F
8. T2
9. Maximum
10. Minimum
11. Low Baery/Hold

The PHT-771 may be used with an oponal second sensor (not provided).
For general temperature, humidity, wet bulb and dew point measurements
a second sensor is not necessary.
 
A. Turn the unit ON and hold the probe in the area to be
tested.
B. Allow approximately 60 to 80 seconds for readings to stabi-
lize.
C. The Relave Humidity measurement appears in the top
display.
D. Pressing the buon toggles the lower le display between DP (Dew Point) and T1 (Ambient
Temperature).
E. Wet Bulb (Wb) is displayed in lower right display.
F. If second sensor is installed, pressing the buon toggles the lower right display between
T2-DP (external temperature-Dew Point), WB (Wet Bulb), and T2 (external temperature).
5
Rev. C / October 2011
PHT-771 Digital Psychrometer


If an external probe is not connected, T1-T2, T2-DP,
and T2 measurements will not be displayed.
 
A. The PHT-771 default is to display Wet Bulb Wb in the lower right display. Wb is displayed in ° C or
° F. The Wet Bulb measurement is an indicaon of evaporave cooling and will be lower (cooler)
than the ambient Temperature T1 measurement.
B. To read the Dew Point measurement, press the buon in unl the symbol DP appears in
the lower le display. DP is displayed in ° C or ° F. The Dew Point measurement is an indicaon of
the temperature at which moisture in the air will condense.
 
A. To read the Wet Bulb measurement, press the buon unl the symbol Wb appears in the
lower right display. Wet Bulb temperature is now displayed in ° C or ° F.

An external probe must be connected to acvate the buon.
B. To read the Dew Point measurement, press the buon in unl the symbol  appears in the
lower le display.  is displayed in ° C or ° F.
 
A. The MIN/MAX mode allows the user to view only the lowest () or highest () readings.
B. Press the buon once and MIN appears on the display. The display is now showing the low-
est humidity and temperature reading in memory.
1. If is in Dew Point mode, the MIN Dew Point () will be displayed.
2. If is in Temperature mode, the MIN Temp. () will be displayed.
3. The minimum Wet Bulb (Wb) will be displayed.
C. Press the buon again and MAX appears on the display. The display is now showing the
maximum humidity and temperature readings in memory.
6Rev. C / October 2011
PHT-771 Digital Psychrometer

1. If is in Dew Point mode, the MAX Dew Point (DP) will be displayed
2. If is in the Temperature mode, the MAX Temp. (T1) will be displayed.
3. The maximum Wet Bulb (Wb) will be displayed.
D. To exit the MIN/MAX mode, press the buon again and the MIN and MAX icons disappear.
E. To clear the current min/max readings in memory, press and hold the buon for more than
two seconds.

A. Press the HOLD buon momentarily to freeze the displayed reading.
1. The current reading is now being held and will not change unl Hold (HLD) funcon is can-
celed.
2. To cancel the Hold ) funcon, press the  buon momentarily
B. The ‘’ icon will appear on the upper right-hand side of the display.
C. Press the  buon again to return to normal operaon.
 
A. The meter automacally shuts o aer a programmed period of me
B. The default me is 10 minutes.
C. To modify the Automac Power O ming period:
1. Press the HOLD buon while turning the meter ON using the ON/OFF buon.
2. Connue to hold down both HOLD and ON/OFF buons and the meter will cycle through the
selectable power-o mes: n, 2, 5, 10, 20, 40 or 60 minutes. “n” disables the auto power o
funcon.
3. When the desired power-o me appears in the display, release both buons to select the
displayed me.
4. When both HOLD and ON/OFF buons are released, the unit returns to normal operaon.
7
Rev. C / October 2011
PHT-771 Digital Psychrometer

 
A. When the baery power falls low, the symbol will appear on
the LCD
B. Replace the two (2) 1.5 ‘AAA’ baeries by removing the rear bat-
tery compartment cover and accessing the baery compartment.
C. Observe polarity when placing the baeries in the compartment.
D. Ensure that the compartment cover is securely fastened when
nished.
Remember Low Baeries will tend to give inaccurate readings.
Make sure you have good baeries at all mes.

DO NOT IMMERSE PROBE INTO LIQUIDS. IMMERSING
IN LIQUIDS WILL CAUSE PERMANENT DAMAGE TO
THE SENSOR!
 
An error message will appear on the display if the meter fails an internal diagnosc test.
A. ER1: Relave Humidity failure. Repair/replacement is necessary.
B. ER2: Internal temperature failure. Repair/replacement necessary.
C. ER3: Reference resistance failure. Repair/replacement necessary.
D. ER4: Internal temperature is out of range.
E. ER5: External temperature is out of range.
 

A. The meter should be cleaned with a damp cloth and mild detergent when necessary. Do not use
solvents or abrasives.
B. Store the meter in an area with moderate temperature and humidity (refer to the operang and
storage range in the specicaons chart).
8Rev. C / October 2011
PHT-771 Digital Psychrometer

9
Rev. C / October 2011
PHT-771 Digital Psychrometer


Function Range and Resolution Accuracy
Humidity 0.0 to 100.0% RH ±3% RH (10 to 90%) @ 23 ° C
Temperature (internal) -4.0 to 122.0 ° F (-20 to 50 ° C) ±1.8 ° F (±1 ° C)
Temperature (external) -4.0 to 158.0 ° F (-20 to 70 ° C) ±1.8 ° F (±1 ° C)
Display: Triple LCD
Sensor Type: Humidity: Precision capacitance sensor
Temperature: Thermistor
Response Time: 60 seconds typical
Dew Point: -90.4 to 122.0 ° F (-68 to 50 ° C) (calculated from RH and Air temperature
measurements)
Wet Bulb: -6.88 to 122.0 ° F (-21.6 to 50 ° C) (calculated from RH and Air temperature
measurements)
Operang Condions: -4 to 122 ° F (-20 to 50 ° C); < 99% RH non-condensing
Storage Condions: -40 to 185 ° F (-40 to 85 ° C); <99% RH non-condensing
Power Supply: 2 x 1.5V ‘AAA’ baeries
Baery Life: Approx. 80 hours
Dimensions / Weight: 7 x 1.9 x 1” (178.5 x 48.8 x 25.2mm); 4.9 oz. (140g)
10 Rev. C / October 2011
PHT-771 Digital Psychrometer

Specicaons are subject to change without noce.
All Prostat trademarks and trade names are the property of Prostat Corporaon.
All other trademarks and trade names are the property of their respecve companies.
PROFESSIONAL STATIC CONTROL PRODUCTS
Prostat Corporaon
Corporate Headquarters • 1072 Tower Lane • Bensenville, IL 60106 • 630-238-8883 • Fax: [phone] • 1-855-STATIC1 • www.prostatcorp.com