PRESSURE TRANSDUCERS

865 Series – Very Low Differential
Pressure Transducers
 For Air or Non-Conductive Gas
 0.25 to 100 Inches in W.C.(differential)/±0.1 to ±50 Inches in W.C. (bidirectional)
 High Proof Pressure
The 865 Series are very low-pressure transducers for ranges as low 0.25˝ W.C.
and feature ±1% full scale static accuracy. Primarily used in Building Energy
Management, these transducers are capable of measuring pressures and flows
with the accuracy necessary for proper building pressurization and air flow control.
865 Series transducers utilize an all-stainless steel micro-tig welded sensor thatallows up to 10 psi overpressure (in either direction) with no damage to the unit. Allsensor components have thermally matched coefficients, which promote improved
temperature performance and excellent long-term stability.

Common Specifications
Input
Pressure Range
0.25˝ to 100˝ WC
Proof Pressure
10 psiFatigue Life
10 psi, max.
Performance
Supply Voltage (Vs)
9-30 VDC
Accuracy±1.0% FS (Standard); .4% & .25% versions available
Thermal Error Zero
±0.033% FS/°F (±0.06% FS/°C)
Thermal Error Span
±0.033% FS/°F (±0.06% FS/°C)
Compensated Temperatures 0°F to +150°F (-18°C to +65°C)
Operating Temperatures
0°F to +150°F (-18°C to +65°C)
Storage Temperatures-40°F to +185°F (-40°C to +85°C)
Zero Tolerance
1% (.5% for high accuracy option)
Span Tolerance
1% (.5% for high accuracy option)
Mechanical Configuration
Pressure Port
1/4˝ Fitting
Wetted Parts
Stainless Steel and Glass-Filled Polyester
Electrical Connection
Screw Terminal Strip
EnclosureFire Retardant Glass-Filled Polyester;
Option A1 Conduit Enclosure Available
Approvals
CEWeight
3 ozIndividual Specifications
Voltage Output Units
OutputMin. Load Resistance
Current Output Units
OutputMax. Loop Resistance

G-32

New!

www.gemssensors.com

0-5 VDC (see ordering chart)
5000 kohms
4-20 mA (2 wire)(Vs-9) x 50 ohms

Applications• HVAC• Energy Management Systems• Variable Air Volume and Fan Control (VAV)• Environmental Pollution Control• Static Duct and Clean Room Pressures• Oven Pressurization and Furnace Draft Controls

How They Operate
A tensioned stainless steel diaphragm and insulated
stainless steel electrode, positioned close to thediaphragm, form a variable capacitor. Positive pressure
moves the diaphragm toward the electrode, increasing
the capacitance. A decrease in pressure moves thediaphragm away from the electrode, decreasing thecapacitance. The change in capacitance is detected
and converted to a linear DC electrical signal by Gems’
unique electronic circuitry.

CAPACITANCE TYPE
Dimensions
Optional Conduit Enclosure – Code A1

PRESSURE TRANSDUCERS

Standard 865 Series
0.385
10

MODEL 865

1.67
42
HIGH

2.74
70

3.16
80

Plainville, CT U.S.A.

HIGH

3.34
85

Plainville, CT U.S.A.
LOW+–4.33
110

1.41361.00
25

LOW(RANGE)
0.61
160.156
DIA.
4
MOUNTING HOLE
2 PLACES

0.875 DIA.
22
FOR CONDUITFITTING

6-32 SCREWW/TERMINALWASHERS
3 PLACES
1.64
42

1.89
48

1.94
49.3

1.56
40

0.80
20
1.10
28
2.1956

How to Order
Use the bold characters from the chart below to construct a product code.
SELECT

8651 - OR5WD - 2B - T1 - C

Series8651 - 865 Series
Pressure Range Code
Unidirectional
Code Range (Inches W.C.)
R25WD
0 to 0.25
OR5WD 0 to 0.5001WD
0 to 1.0
2R5WD
0 to 2.5005WD
0 to 5.0010WD
0 to 10.0025WD
0 to 25.0050WD
0 to 50.0
100WD
0 to 100.0

Bidirectional
Code Range (Inches W.C.)
OR1WB
±0.1
R25WB
±0.25
OR5WB
±0.5001WB
±1.0
2R5WB
±2.5005WB±5.0010WB±10.0025WB±25.0050WB±50.0

AccuracyC - ±1% FS (Standard)
Options:
E - ±0.4% FS – Calibration Certificate supplied
F - ±0.25% FS – Calibration Certificate supplied
G - ±1% FS – Calibration Certificate supplied
Electrical Connection
T1 - Terminal Strip
A1 - Supplied with Optional 7/8˝ Knock-Out Hole for 1/2˝Conduit Enclosure

Output11 - 4-20 mA (9-30 VDC excitation)
2B - 0-5 VDC (9-30 VDC excitation)

www.gemssensors.com

G-33