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expense resulting from errors or omissions. In the interest of technical improvement, this specification may be altered without notice.
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GS-AQ521
Issue: 5.6
Date Of Issue: 22/09/2010
© 2010 Sontay Limited. All rights reserved.
Technical Overview
The GS-AQ521 is duct-mounting air quality transmitter de-
signed for use for the control of fresh air for ventilation
purposes. The GS-AQ521 measures the level of contaminant
gases in an air sample, and is sensitive to most heavy
odours, smoke, solvent gases etc., providing an output pro-
portional to the mixed gas concentration. This signal can be
used to control fresh air fans and dampers according to the
ventilation load. Where the primary contaminant load is
human respiration, it is recommended that a Carbon Dioxide
transmitter is used.
Installation
1. Select a location in the duct where dust & contaminants
are at a minimum (i.e. after filters etc.) and which will
give a representative sample of the prevailing air condi-
tion.
2. If the sensor is to be mounted outside, it is recom-
mended that the unit be mounted with the cable entry
at the bottom. If the cable is fed from above then into
the cable gland at the bottom, it is recommended that a
rain loop be placed in the cable before entry into the
sensor.
3. Drill two holes at 85mm centres, fix the IP65 housing to
the duct with appropriate screws. Making sure to align
the holes in the probe so they point into the air flow.
The housing is designed to make it easy for an electric
screwdriver to be used if desired.
4. Remove the front cover by twisting the lid and separat-
ing from the main body.
5. Feed the cable through the waterproof gland and termi-
nate the cores at the terminal block. Leaving some
slack inside the unit, tighten the cable gland onto the
cable to ensure water tightness.
6. Replace the lid after the electrical connections have
been made.
7. Power the unit with 24Vac/dc and after a stabilising
period of 2-3 minutes functionality checks can be made.
8. Pre-commissioning checks are made after approximate-
ly 30 minutes. Final commissioning should only be car-
ried out after the unit has been running for a minimum
of seven days.
Operation
The GS-AQ521 duct air quality transmitter is most suited to
areas such as common rooms, canteens, office spaces and
other areas where pollutants given off by occupants are of
concern.
The typical pollutants of which the GS-AQ521 would monitor
are body odours, methane, solvent gases, cigarette smoke,
carbon monoxide, alcohol, perfume and most other heavy
odours related to high occupancy.
The normal operation of the GS-AQ521 is to set the damp-
ers to minimum fresh air at below 2Vdc. As the signal in-
creases, dampers should be modulated to fully open at 8-
10Vdc.
Connections
NB Jumpers LK1 & LK2 should not be changed.
Do not adjust the CAL & SPAN potentiometers.
Trend Scaling
Typically, the output could be scaled for 0 to 100% contami-
nation.
Brange -100
Trange 100
Upper 100
Lower 0
Exponent 3
Output
+24V
0V
LK1 LK2
1 2 3
CAL SPAN
