CTI GG-VL2-R User manual

Installation and Operation Manual
GG-VL2-R REFRIGERANT VENT LINE SENSOR

2GG-VL2-R
Warning
Use this product only in the manner described in this manual.
If the equipment is used in a manner not specied by Calibration
Technologies, the protection provided by the equipment may be impaired.
This equipment should be installed by qualied personnel.

GG-VL2-R 3
Table of Contents
General description ........................................ 4
Installation ....................................................... 4
Locating the sensor .................................... 4
Installation guidelines ................................. 5
Wiring .......................................................... 6
Operation ......................................................... 7
Start-up ........................................................ 7
Calibration ................................................... 7
Maintenance..................................................... 9
Troubleshooting............................................. 10
Specications ................................................. 10
Warranty......................................................... 11 For technical support, contact:
Calibration Technologies
920 N Tradewinds Pkwy
Columbia, MO 65201
866-394-5861
[email protected]
www.ctiengineering.com

4GG-VL2-R
General Description Installation
The GG-VL2-R Vent Line detector is a +24 VDC,
three-wire, 4/20 mA sensor for CFC, HFC and HCFC
refrigerant gases. It provides an industry standard
linear 4/20 mA output signal compatible with most gas
detection systems and PLCs.
The GG-VL2-R provides real-time continuous
monitoring of refrigerant vapors in refrigeration
system vent lines. Utilizing a rugged and long-life
solid-state sensor, the GG-VL2-R sensor withstands
continuous exposures to high concentrations of
vapors, without shortening the life of the sensor.
The sensor element can be accessed from inside of
the stainless steel enclosure, and is sealed from the
vent line to prevent refrigerant from entering the
enclosure.
The transmitter circuit board is sealed in potting
compound, protecting sensitive electronic
components and copper tracing from corrosion. The
stainless steel enclosure protects the transmitter from
chemical and UV damage.
Recommended alarm setpoints for refrigerant vent
lines are typically 0.5 – 1.0% (12 – 20 mA). Setpoints
lower than this may result in occasional false alarms
due to inclement weather or interference gases (e.g.
truck exhaust, condenser steam, etc.)
Locating the sensor
Warning: Outdoor installation only. Never install
the sensor indoors (e.g. Engine Room)
Note: The ½” nipple of the supplied mounting kit
should be welded to the relief header to allow airow
to the sensor.
Note: Removing the ½” plug from the mounting
kit usually allows more fresh air to the sensor and
prevents signal rise over time.
The GG-VL2-R sensor assembly should be installed
outdoors three to ve feet above the rooine, where
the relief header discharges to the atmosphere (see
Figure 1).

5
GG-VL2-R
Installation Guidelines:
• Always assume system could discharge at any
moment. Stay clear of discharge path and have
escape route planned.
• Make sure refrigerant does not discharge onto
sensor assembly or personnel working on sensor
(i.e. mount sensor opposite side of discharge).
• Install sensor enclosure with conduit hole facing
down.
Figure 1: Discharge to Atmosphere

6GG-VL2-R
Wiring
Electrical wiring must comply with all applicable codes.
Electrical Power: 24 VDC regulated, 85 mA.
Output: Linear 4/20 mA output. Monitoring
equipment may have a maximum input impedance
of 700 ohms.
Cable Recommendation: 20/3 shielded cable
(General Cable C2525A or equivalent). Length of cable
to sensor should be no greater than 1,500 ft.
Monitoring: Monitoring equipment must be
congured to indicate a fault if the signal is below
1 mA. All signals over 20 mA must be considered
high gas concentrations. Alarm setpoints should
not be lower than 50% of full-scale range.
Wiring Guidelines:
• Use only the existing conduit hole for connections
to the sensor.
• Always use three conductor, insulated, stranded,
shielded copper cable.
• Do not pull detector wiring with AC power cables.
This can cause electrical interference.
• If cable runs cannot be made without a splice, all
splice connections should be soldered.
• Ground the shield at the main control panel.
Connect the shield wire in the sensor terminal block
labeled SHLD.
• Always disconnect power at the controller before
performing any wiring at the sensor.
Terminal Block Plug (Field Wiring):
SHLD: To case (earth) ground of monitoring equipment
GND: To ground terminal of power supply
+24V: To +24V terminal of power supply
SIG: To signal input of monitoring equipment
Figure 2: Wiring Diagram

7
GG-VL2-R
Operation
Start-up
Before applying power, make a nal check of all wiring
for continuity, shorts, grounds, etc. It is usually best to
disconnect external alarms and other equipment from
the detector until the initial start-up procedures are
completed.
After power-up, allow at least 1 hour for the system
to stabilize before testing the detectors. Because
detectors are normally located at a distance from
the main unit, the test time required and accuracy of
the response checks will be improved if two people
perform the start-up procedures and use radio
contact.
Response Test:
1. One person exposes each sensor to 1% R507a
calibration gas.
2. The second person stays at the control panel to
determine that each sensor, when exposed to
the gas, is connected to the proper input and
responds, causing appropriate alarm functions.
Calibration
The GG-VL2-R detector has a similar response to most
common halocarbon gases. For ease of bump testing
and calibration, we recommend using 1% R507a for
bump gas and calibration gas. If target gas is preferred
or required, please inquire with CTI sales sta for help
obtaining specic calibration gases.
The GG-VL2-R detector comes factory calibrated
and should not require any adjustments after
installation. If any adjustments are required, there
are two pots on the preamp that are used for
calibration.
Note: Never measure sensor output in mA.
Always use mVDC or VDC voltmeter settings.
Zero Calibration: After the unit is installed and
powered up, the unit can be zero calibrated by the
following:
• Be sure the unit is in clean air. This can be
accomplished by applying zero air calibration gas
or removing the detector from the mounting kit
into fresh air.
• Adjust the zero pot until the detector outputs 40
mV from Test [-] to Test [+] (see Figure 3).
Span Calibration: It is recommended that the
GG-VL2-R sensor be response tested only, every six
months. Refer to the Response Test procedure on
this page.
If span calibration is required, the following
procedure will span the unit:
• Unscrew calibration port cover and connect cal
gas hose to hose barb tting (see Figure 3).
• Apply 1% R507a span gas at 0.5 - 0.8 L/min.
• Once the output signal has peaked (or two
minutes maximum) adjust the span pot until the
sensor outputs 200 mV from Test [-] to Test [+]
(see Figure 3).

8GG-VL2-R
Figure 3: Sensor Output and Zero/span Adjustments
40-200 mV
mVDC
Black Red
-+
Calibration port
Unscrew cap to
apply cal gas
Zero and Span
adjustments
Sensor element
assembly

9
GG-VL2-R
The GG-VL2-R sensor was designed for long life and
minimal maintenance. Calibration Technologies
recommends the following maintenance schedule:
Maintenance Guidelines:
• The sensor is shipped with a factory calibration and
should be response-tested every 6 months.
• Response-test the sensor at least once every 6
months with 1% R507a calibration gas.
• All tests and calibrations must be logged.
• Always disconnect power at the controller before
performing any wiring at the detector.
Sensor Life: Typical sensor element life of the GG-
VL2-R detector is ve to seven years. A few conditions
can cause the sensor element to become faulty,
including:
• a long period of time
• exposure to liquid
Maintenance Sensor Element Replacement: When the sensor
element becomes faulty, a replacement sensor
element can be obtained from CTI. To replace the
sensor element, refer to Figure 3 and the following
procedure.
Caution: Always assume the system could
discharge at any moment. Stay clear of discharge
path and have an escape route planned.
1. Be prepared for fault/alarm conditions during this
process.
2. Remove power from detector. This can be done by
simply unplugging the 4-position power plug from
the transmitter.
3. Unplug sensor element cable from transmitter.
4. Unscrew the sensor element assembly and discard
old sensor element.
5. A replacement O-ring is included in case existing
O-ring is damaged or lost.
6. Screw in new replacement sensor element
assembly (do not overtighten).
7. Plug in sensor element cable to transmitter.
8. Re-apply power to detector.
9. The detector can be response-tested immediately
after replacement but allow 1-hour warm-up time
before performing zero/span calibration.
Sensor Element:
For all halocarbons, use part #: GG-VL2-R-RS

10 GG-VL2-R
Specications
Input Power: +24 VDC, 85 mA
Detection Principle: Solid-state
Detection Method: Diusion
Gas: CFC / HFC / HCFC refrigerants (R11, R12, R22,
R134a, R404a, R410a, R434a, R507a, etc.)
Range: 0/1% (10,000 ppm)
Output Signal:
Linear 4/20 mA (max input impedance: 700 Ohms)
Deadband: 12 mA or 50% full-scale
Response Time: T90 = less than 30 seconds
Accuracy: +/- 5% of full-scale
Zero Drift: Less than 1% per month
Span Drift: Less than 1% of full-scale per month
Linearity: +/- 5% of full-scale
Repeatability: +/- 5% 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-classied areas.
Mounting Kit: Schedule 80 NPT pipe ttings
Temperature Range: -46°F to +140°F (-46°C to +60°C)
Dimensions: 5.48” high x 4.90” wide x 2.93” deep
Weight: 4 lbs (includes mounting kit)
Certication:
SGS Listed:
Conforms to UL 61010-1
Certied to CSA C22.2 No. 61010-1
Troubleshooting
Sensor Fault: (low signal reading)
Indications: (any or all)
• Red LED on transmitter lit.
• Voltage signal at testpoints is 5 mVdc (.5 mA output).
• PLC displays negative value (e.g. -2150 ppm).
• Controller indicates sensor fault or sensor failure
Possible Cause / Solution:
• Sensor exposed to liquid. Replace sensor element
(see page 9 for more info).
• Loose connection. Check and tighten sensor wires.
Constant or Intermittent high signal or alarms:
Indications:
• Erratic or constant high concentration reading at
controller or PLC.
Possible Cause / Solution:
• Weeping relief valve. Check valve by drawing a
sample from the header with an accurate portable
refrigerant 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.
• Condenser steam. Re-install the ½“ plug or install
pipe in its place, lowered below the condenser
steam level to allow a fresh-air vent to the sensor.
• Sensor aged beyond its useful life (hypersensitive).
Replace sensor element (see page 9 for more info).