Vaisala 26150GM QUICK REFERENCE GUIDE

Quick Reference Guide

Field Check Adapter

26150GM

FIELD CHECK OF AMMONIA DETECTORS

The performance of the Vaisala AMMONICAP® Ammonia
Detector Series AMT100 can be checked on site with ammonia
gas. A field check ensures the detector is functioning and the
sensor responds to ammonia gas.

During the field check, the sensor is purged using a reference gas
with a known ammonia concentration. The ammonia gas causes
alarm signals (in the case of AMT100 Series, led lights) to turn
on, thus indicating that the detector is functioning.

Note that a field comparison can only check the performance of
the detector. For accurate calibration and adjustment, the probe
or the detector should be returned to Vaisala Service (see table
on the reverse side).

Field Check Equipment

To perform a field check, certified calibration gas, a pressure
regulator, a field check adapter, and flexible tubes (preferably
teflon) with inner diameters of 4 mm and 6 mm are required.

Reference gas, pressure regulators and the field check adapter
can be ordered from Vaisala with the following order codes:

• Ammonia reference gas 100ppm 210374

• Ammonia reference gas 300ppm 210375

• Pressure regulator 210376

• Field check adapter 26150GM

gas outlet pipe is 6 mm, and the diameter of the field check
adapter’s inlet is 4 mm.

4. Open the bottle valve and let the reference gas flow through
the adapter. The regulator’s preset flow rate is 0.5 l/min.

5. Let the gas flow for 2...5 minutes. (If you want to check the
exact reading or if the reference concentration is very close to
the alarm level, let the gas flow for at least 5 minutes to establish
a stabilized environment.)

6. The low level and high level leds are lit as the ammonia
concentration on the sensor exceeds the two alarm setpoint
levels. This indicates that the detector reacts to ammonia and that
the alarms are functioning.

7. On completion, close the bottle valve and detach the adapter
from the probe.

8. When the readout has dropped below the alarm levels, turn the
detector back to normal operation mode by pressing the
SERVICE MODE button.

– Tool for easy field checking

– Compatible with Vaisala AMMONICAP

Ammonia Detector Series AMT100 and
Vaisala CARBOCAP

®

Carbon Dioxide Probes

Series GM220

100 ppm reference gas is recommended for probes with a 0...100
ppm measuring range. For probes with a 0...1000 ppm measuring
range, the 300 ppm reference gas is recommended.

The gas bottles contain 34 liters of ammonia compressed into a
small and light (1 lb/0.44kg) container. The bottles are not

®

refillable. The pressure regulator, however, can be used again.

Field Check Instructions

1. Turn the detector to SERVICE MODE either by pressing the
button or via the serial line connection. When the detector is in
service mode, the operation light is blinking.

2. Place the field check adapter onto the probe.

3. Connect the reference gas bottle to the adapter inlet (at the
bottom of the adapter) with flexible tubing. The diameter of the

Field checking ammonia detector.

M210450en-A

FIELD CHECK OF CARBON DIOXIDE
TRANSMITTERS

The field check adapter for Vaisala CARBOCAP¨ Carbon
Dioxide Probes Series GMP220 can be used as

- a chamber for feeding in reference gas in a field checking

of the probes

- a chamber for pump aspirated sampling system.

Note that a field comparison can only check the performance of
the transmitter. For accurate calibration and adjustment, the
probe or transmitter should be returned to Vaisala Service
Centre.

Field Check Equipment

• Accurate reference gas (Basically any concentration within

the measurement range will do. If available, a good choice
is one close to the normal measurement concentration.)

• A pressure regulator for reducing the pressure of the

calibration gas

• A flow meter to adjust the gas flow

• Tubing with 3mm (1/8") inner diameter (for example

neoprene tubing, part no. 18229. (Teflon tube NOT
recommended).

• The field check adapter (part no. 26150 GM)

Field Check Instructions for the GMT220-series

1. Attach the adapter to the probe of your GMT220 series
transmitter. The adapter fits both the probe sizes available
(GMP221 and GMP222) and can be attached to a probe on a
transmitter as well as one attached to a cable. Push the adapter
up the probe. Connect tubing to the bottom port of the adapter.

2. Connect the adapter with the tubing to the flow meter, the
pressure regulator, and further to the reference gas bottle. The
other port of the adapter is left open for gas outflow.

GMT220/ GMM220 series
transmitter

flow meter

pressure regulator

CO

2

3. Let the reference gas flow through the pressure regulator and
the flow meter to the adapter. The recommended flow rate is 0.6
l/min. Let the transmitter stabilize for 5 minutes.

4. Check the reading on the display, or if the transmitter has no
display, from the analog output. If the difference between the
reading and the reference gas concentration after pressure and
temperature correction is more than the accuracy and long-term
stability specifications allow, detach the probe and send it to
Vaisala for adjustment.

Note when installing the probe

- The probe should be pushed into the adapter deep enough, so

that none of the diffusion holes will be outside the adapter
chamber.

- Also the excess space inside the chamber should be

minimized by pushing the probe well inside the chamber
(this is especially important if using the field check adapter
with inadequate gas flows of below 0.4 l/min)

Important note for the GMP221 !

When using the shorter probe (GMP221) with the Field
Check Adapter, the adapter must be inserted on the probe
so that the o-ring inside the adapter is not on the sticker of
the probe (see Figure). If the adapter is placed on the
sticker, the seam between the probe and the adapter will
let the gas leak from the chamber.

O-ring inside the adapter shall
not be on the sticker of the
probe !

The Field Check Adapter and a GMP220 Series probe.

VAISALA SERVICE CENTERS

NORTH AMERICAN SERVICE CENTER
Vaisala Inc., 100 Commerce Way, Woburn,

MA 01801-1068, USA.
Phone: [phone], Fax [phone]
Email: [e-mail]

EUROPEAN SERVICE CENTER
Vaisala Instruments Service, Vanha Nurmijärventie 21

FIN-01670 Vantaa, FINLAND.
Phone: [phone], Fax [phone]
E-mail: [e-mail]

ASIAN SERVICE CENTER
Vaisala KK, 42 Kagurazaka 6-Chome, Shinjuku-Ku,

Tokyo 162-0825, JAPAN.
Phone: [phone], Fax [phone]
E-mail: [e-mail]

www.vaisala.com

www.vaisala.com