CTI GG-VL2-NH3, Installation And Operation Manual

GG-VL2-NH3

11

Specifications

Input Power:

 +24 VDC, 80 mA

Detection Principle: 

Catalytic bead

Detection Method: 

Diffusion

Gas: 

Ammonia (NH3)

Range: 

0-1% (10,000 ppm) with 0.25% NH3 deadband

Output Signal: 

Linear 4/20 mA (max input impedance: 700 Ohms) 

Response Time: 

T90 = less than 30 seconds

Accuracy: 

+/- 2% of full-scale

Zero Drift: 

Less than 0.1% of full-scale per month

Span Drift: 

Less than 2% of full-scale per month

Linearity: 

+/- 1% of full-scale

Repeatability: 

+/- 1% of full-scale

Wiring Connections: 

3-conductor, shielded, stranded, 20 AWG cable 

(General Cable C2525A or equivalent) up to 1500 ft.

Terminal Block Plug (Field Wiring): 

26-16 AWG, 

torque 4 lbs-in.

Enclosure: 

18 gauge stainless steel housing. Captive 

screw in hinged lid. For non-classified areas. 

Mounting Kit: 

Schedule 80 NPT pipe fittings

Temperature Range: 

-40°F to +140°F (-40°C to +60°C)

Dimensions: 

4.8” high x 4.72” wide x 3.35” deep        

Weight:

 4 lbs (includes mounting kit)

Certification:

ETL Listed: Conforms to UL 61010-1

Certified to CSA C22.2

 No. 61010-1

Troubleshooting

Sensor Fault:

 (0.5 mA signal output)

Indications: (any or all)

•  Red LED on transmitter lit and voltage signal at 

testpoints is 5 mVdc (.5 mA output).

•  PLC displays negative value (i.e. -2200 ppm).
•  Controller indicates sensor fault or sensor failure
Possible Cause / Solution:

•  Sensor exposed to liquid. Replace sensor element 

(see page 10 for more info).

•  Loose connection. Check all sensor wires.

Constant or Intermittent high signal or alarms:

Possible Cause / Solution:

•  Gas exposures well above the 0-1% NH3 range 

of the sensor can shorten the life of the sensor 

element, and typically results in a "zero signal 

shift", where the signal is stuck at full-scale level. 

Make sure no ammonia gas is present and simply 

re-zero the sensor following the 

Zero Calibration

procedure.

•  Weeping relief valve. Check valve by drawing a 

sample from the header with an accurate portable 

ammonia detector. Be sure to sample 1’ to 3’ from 

inside the header to ensure a good reading.

• 

Or 

loosen union nut and remove sensor assembly 

from header. If signal returns to normal in fresh air, 

investigate relief valve(s) and replace if necessary.