HVAC Controls CO2-TH User manual

CO2-TH
Indoor CO2, Temperature and Humidity
Monitor
Version 1.3
Page 2
Thank you for your purchase of the CO2-TH CO2, Temperature and Humidity Monitor. This device
has been designed, built, and tested to be an exceptionally reliable product. Great effort has been
taken to ensure ease of use and reliable monitoring of Carbon Dioxide, temperature, and humidity
within an interior space.
Take time to read this manual carefully to understand how the product can be used and applied for
your specific application.
Great care has been taken in the preparation of this manual. However, iO HVAC Controls takes no
responsibility for errors or omissions contained in this document. It is the responsibility of the
installer to ensure that this product and any equipment connected to it operates in a safe and
efficient manner.
Due to ongoing product improvement iO HVAC Controls reserves the right to change the
specifications of this product (or its components) without notice.
All rights reserved. © Specified Controls 2020 Intellectual rights apply.
iO HVAC Controls www.iohvaccontrols.com

Page 3
LCD Display
Not all display elements or buttons shown may be active. The display is dynamic and
functions not applicable will not be shown. The alarm mute button for example, will not
be shown until the alarm is sounding.
Page 4
User Operation
The product requires very little user interaction. It will monitor the levels of carbon
dioxide, humidity and temperature within the applied space and is capable of initiating
alarms and corrective action if any of these exceed pre-set levels.
When enabled, the user can press the “Force Fresh Air” button which will bring in fresh
air. The “Force Fresh Air” button will flash when pressed to indicate that it is running.
When enabled, the LCD backlight can also change the background color from green,
amber, and red to visually indicate the CO2 level in the space.
When enabled, user can mute an audible alarm by pressing the “Mute Alarm” button
when shown. If Active Ventilation is enabled, the user can tap the “A” icon to briefly
display the outside air temperature.

Page 5
Terminal Layout
Use a small, flat bladed
screwdriver and place
it in the bottom center
of the enclosure and
pry to separate the
display from the
subbase. Take care not
to drop the display as
damage may occur.
When reattaching, make sure no wiring is interfering
with the pin connectors.
Hook the top of the display into the top of the base and
swing the lower section in. Press firmly to snap the two
halves together. DO NOT press on the glass display,
press on the plastic only.
Page 6
O-10V Outputs
There are three 0-10V outputs. One each for carbon dioxide, temperature, and relative
humidity. All 0-10V output wiring is the same. Wire between the required output and the
0V / Com terminals. The output voltage will increase with increasing temperature,
humidity, or carbon dioxide levels. (Default range is 0-2000ppm)
The output
voltage and scale
for each of the
three 0-10V
outputs is
independently
adjustable from
the Installer
options menu.
(See installer
options starting
on page 16)

Page 7
Relay
There is a single volt free relay with changeover contacts. The relay is rated to carry 30V
@1A Max. Any voltage applied to the relay common terminal will switch between the
normally open (NO) and normally closed (NC) terminals. This relay can be set to respond
to high levels of temperature, relative humidity or carbon dioxide as selected in the
installer options. Each sensor has its own selectable alarm threshold.
You can assign just one sensor, such as CO2 to the relay,
or multiple sensors such as Temperature and RH to the relay.
The Installer menu options will permit you to set this relay as a normally de-energised or
as a fail-safe normally energised relay. This will change the NO/NC wiring logic.
T1 T2
A single universal input has been provided that will permit several
additional functions to be performed. This input can be used as a
remote temperature sensor input or as a volt free switch input that
can control many functions. A complete list of options available to
this input are available in the Installer options menu.
Page 8
Power
Primary power can either be AC or DC from 12 to 30V.
AC power is not polarity dependent however if using DC power ensure the positive
voltage is applied to the top AC+ terminal and negative to the
lower AC- terminal. Reverse polarity DC wiring will not cause
damage but will simply will not power on.
Communications
This product has isolated RS-485 communications capability. You can select either
Modbus RTU or BACnet MSTP communications protocol from within the Installer menu.
For detailed communications capabilities and information on all data points available,
separate communications documentation is available

Page 9
Power Up
When you first apply power, the LCD will display all elements and then display the
firmware version for a few seconds. During the next 180 seconds the display will
countdown from 180 to 0 to permit the CO2 and other sensors to stabilize. During this
countdown period no alarm conditions will be initiated. All three of the 0-10V outputs
will be held at their respective “safety voltage” as defined in the Installer menu (see page
17) and if the alarm relay is set as fail-safe it will energise. The LCD will also cycle its color
backlight through green, amber and red.
Once the countdown has reached zero, normal function will begin.
Important Notes
The CO2 sensor has an advanced learning self-calibrating function. This calibration
process takes place over an 8-day period. It is therefore essential that power remains
constant during this period.
Page 10
Installation & Mounting
All sensing devices are contained within the enclosure. Therefore, it is important to locate
it within the space to be monitored and controlled.
The monitor should be installed in a location that represents the ambient space
temperature. Do not install in an area where drafts are present, near the floor, behind
doors or on an external wall.
Avoid mounting in an area where air movement is limited, affected by direct sunlight or
other areas not typical of the normal space conditions.
After mounting the subbase, be aware that drafts may travel down wall cavities. It is
important to seal the wire access hole to prevent any drafts that might affect the internal
sensors.

Page 11
Advanced Installer Options Menu
This product can be configured to meet the requirements of the specific application.
Within the Advanced Installer options menu, you can adjust how the monitor will
responds to and report the levels of carbon dioxide, temperature, and humidity.
Make sure that you understand any changes made in this Installer options menu and if
not, contact Specified Controls for clarification and advice.
To enter the Installer menu first tap then
press and hold the center of the display.
After 10 seconds the display will change and
show the digits “15" (fifteen) along the Up /
Down arrows and the NEXT button. Use the
Up (or Down) arrow to adjust the display to
“21" (twenty-one) or your previously saved
PIN. Press the NEXT button to enter the
menu. If you are returned to the previous screen, you have entered the incorrect PIN.
Try again
Page 12
To advance through the menu items tap the “NEXT” button and adjust the shown
installer option with the Up / Down arrows.
To exit the Installer menu and save changes press and hold the “NEXT” button for 3
seconds.
After making changes in this menu DO NOT power down for
20 seconds or changes may be discarded.
1
PIN
This sets the PIN to enter the
I
nstaller options menu for future
entry. Please record any changes made to the PIN as it will affect
how you enter the Installer options menu in the future.
Default PIN is 21. Range is from 00 to 99.
2
Display Temp
You can display the room Temp in
d
eg
ree
C,
d
eg
ree
F or hide the
display of room temperature.
Default is deg
ree
Off
. Options are C, F or O
ff
.
3
Display RH
You can display or hide the room humidity display.
Default is
Off
.
Options are On or Off.
4
Display CO2
You can display the room CO2 in ppm or percentage to alarm point
or hide the CO2 display. 0% being displayed is clean fresh air
(400ppm) and 100% displayed being at alarm point.
Default is
ppm
. Options are ppm, % or O
ff.

Page 13
5
Calibrate
Temp
Should you feel
that the temperature sensor accuracy has drifted
you are permitted to apply a small, fixed offset.
Default is 0.0. Options are +/- 5 deg C or F in 0.1 deg steps.
6
Calibrate RH
Should you feel that the humidity sensor accuracy has drifted you
are permitted to apply a small, fixed offset.
Default is 0%. Options are +/- 25% in 1% steps.
7
Calibrate
CO2
Should you feel that the CO2 sensor accuracy has drifted you are
permitted to apply a small, fixed offset.
Default is 0ppm. Options are +/- 100ppm in 1ppm steps.
Caution! The NDIR sensor is extremely stable and accurate.
Investigate all other causes for perceived errors before adjusting.
8
Temperature
Alarm Relay
You
can
set a temperature value that will turn on the volt free
alarm relay.
Default is Off. Options are Off, then -20 to +120 (C or F) in 1-degree
steps.
9
RH
Alarm
Relay
You
can
set a
r
elative humidity value that will turn on the volt free
alarm relay.
Default is Off. Options are Off, then 0% to +100% in 1% steps.
10
CO2
Alarm
Relay
You
can
set a carbon dioxide value that will turn on the volt free
alarm relay.
Default is 800 ppm. Options are OFF, then 400ppm to 2000ppm in
50 ppm steps.
Page 14
11
Alarm Relay
Logic
You can
apply
the alarm relay as a normally
de
-
energised or as a
normally energised (failsafe) relay. If normally energised the alarm
relay will energise on power up and de-energise in an alarm
condition or loss of power.
Default is 0 - Normally de-energised.
Options are 0 - Normally de-energised or 1 - Normally energised
12
Beeper
The
monitor
is fitted with a
solid
-
state
beeper. This beeper can be
used to acknowledge a button press as well as be used for an
alarm.
Default is 1 = Beep on button press.
Options are 0= No beeper. 1 = Beep on button press.
2 =
B
eep on alarm. 3
= Beep on button
press
&
a
larm.
13
Beeper
Mute
The beeper may be set to sound when in alarm condition. If
desired,
you can show a beeper mute button when this occurs.
Default is 0 = Do not permit mute.
Options are 1 = Toggle mute. 2 = 1 Hour mute. 3 = 3 Hour mute. 4 =
12
H
our
mute.
14
Show
Force
Fresh Air
Button
The
SC
-
CO2
-
TH
display can be set to show a “force fresh air”
button. If this button is pressed the CO2 sensor 0-10V output will
go to maximum voltage and the alarm relay (if set for CO2) will
engage.
Default is 2 = Show FFA & auto reset after 1 hour.
Options are 1 = Show FFA. 2 = Show FFA & auto reset after 1 hour.
3 = Show FFA and auto reset 4 hours.

Page 15
15
T1
T2
I
nput
Function
The remote inputs have multiple functions including
:
0= Override onboard sensor with remote sensor.
1= Average onboard sensor with remote sensor.
2 = Force fresh air. 3 = Remote mute. 4 = Reserved. 5 = Report
status to Mobus/BACnet. 6 = Outside air sensor. 7 = Pause all
alarms (Unoccupied). Default is 0.
16
Active
Ventilation
High Outside
Air
Temperature
Lockout
The
A
ctive
V
entilation function uses the inside and outside (if
fitted) air temperature sensors to determine if outside air is
suitable to be used to ventilate the room.
The outside air temperature must be under this value to be
deemed suitable for the Active Ventilation function to operate.
Default is OFF. Adjustments are Off, then 5 degrees to 100 degrees
in 1-degree steps.
17
Active
Ventilation
Low Inside Air
Temperature
Lockout
The
A
ctive
V
entilation function
uses the inside and outside (if
fitted) air temperature sensors to determine if outside air is
suitable to be used to ventilate the room.
This setting defines the inside air temperature threshold that if
exceeded (and if outside air is suitable) will begin the Active
Ventilation function.
Default is Off. Options are Off, then 5 degrees to 100 degrees in 1-
degree steps.
Page 16
18
Active
Ventilation
Output
The
monitor
can introduce fresh outside air
into the room when
conditions are suitable. This option defines the output(s) that
control this function. The letter “A” will be shown on the display
when this function is enabled and flash when it is working. (Tap
the “A” to see outside temp)
Default is 0 = Function Off.
Options are 0= Function Off. 1 = Relay only. 2 = Temp 0-10V only.
3 = Relay and temp 0-10V.
19
Temp
Min
Value
This option permits you to select the lowest temperature value to
be used. Temperatures below this value will be ignored. (See
graph on page 6)
Default is 0 degrees. Adjustments are -20 degrees to 150 degrees
(C or F) in 1-degree steps.
20
Temp Max
Value
This option permits you to select the highest temperature value to
be used by the SC-CO2-TH. Temperatures above this value will be
ignored. (See graph on page 5)
Default is 100 degrees. Adjustments are -20 degrees to 150
degrees
in
1
-
degree
steps.
21
Temp
Low Voltage
This sets the
minimum
temperature 0
-
10V output voltage when at
the minimum temperature value. (See graph on page 5)
Default is 0V. Adjustments are 0-10V in 0.5V steps.
22
Temp Max
Voltage
This sets the
maximum
temperature 0
-
10V output vol
tage when
at the maximum temperature value. (See graph on page 5)
Default is 10V. Adjustments are 0-10V in 0.5V steps.

Page 17
23
Temp Safety
Voltage
This sets a constant voltage to the temperature 0
-
10V output.
This voltage will be present whenever the SC-CO2-TH is powered.
(See graph on page 5)
Default is 0V. Adjustments are 0-10V in 0.5V steps.
24
RH
Min
Value
This option permits you to select the lowest RH value to be used
by the SC-CO2-TH. RH below this value will be ignored. (See graph
on page 5)
Default is 0 RH. Adjustments are 0 to 100 in 5% steps.
25
RH Max
Value
This option permits you to select the high
est RH value to be used
by the SC-CO2-TH. RH above this value will be ignored. (See graph
on page 6)
Default is 100%. Adjustments are 0 to 100% in 5% steps.
26
RH Low
Voltage
This sets the RH 0
-
10V output minimum voltage when at the
minimum RH value. (See graph on page 6)
Default is 0V. Adjustments are 0-10V in 0.5V steps.
27
RH
Max
Voltage
This sets the RH 0
-
10V maximum output voltage when at the
maximum RH value. (See graph on page 6)
Default is 10V. Adjustments are 0-10V in 0.5V steps.
28
RH Safety
Voltage
This sets a constant voltage to the RH 0
-
10V output.
This voltage will be present whenever the SC-CO2-TH is powered.
(See graph on page 6)
Default is 0V. Adjustments are 0-10V in 0.5V steps.
Page 18
29
CO2
Min
Value
This option permits you to select the lowest CO2 value to be used
by the SC-CO2-TH. CO2 levels below this value will be ignored.
(See graph on page 6)
Default is 0ppm. CO2 Adjustments are 0 to 2000ppm in 50ppm
steps.
30
CO2 Max
Value
This option permits you to select the highest CO2 value to be used
by the SC-CO2-TH. CO2 levels above this value will be ignored.
(See graph on page 6)
Default is 2000ppm. Adjustments are 0 - 2000ppm in 50ppm
steps.
31
CO2 Low
Voltage
This sets the CO2 0
-
10V output minimum voltage when at the
minimum CO2 value. (See Graph on page 5)
Default is 0V. Adjustments are 0-10V in 0.5V steps.
32
CO2 Max
Voltage
This sets the CO2
0
-
10V maximum output voltage when at the
maximum CO2 value. (See graph on page 5)
Default is 10V. Adjustments are 0-10V in 0.5V steps
33
CO2 Safety
Voltage
This sets a constant voltage to the CO2 0
-
10V output.
This voltage will be present whenever the SC-CO2-TH3 is powered.
(See graph on page 5)
Default is 0V. Adjustments are 0-10V in 0.5V steps.
34
Back light
The back light can be set to provide
an
indication of the current air
quality by changing colour from green to amber to red or simply
illuminate the display in green when a button is pressed.
Default is 2.
Options are 0 = No Back light. 1 = Alarm. 2 = Button press only.

Page 19
35
Amber Temp
Backlight
Threshold
This option sets the threshold of where the backlig
ht turns from
green to amber for temperature.
Default is Off. Options are Off, then 0 to 100 degrees in 1-degree
steps.
36
Red Temp
Backlight
Threshold
This sets the threshold of where the backlight turns from amber
to red for high temperature.
Default is Off. Options are Off, then 0 to 100 degrees in 1- degree
steps.
37
Amber RH
Backlight
Threshold
This sets the threshold of where the backlight turns from green to
amber for humidity.
Default is Off. Options are Off, then 0 to 100 % in 1 % steps.
38
Red RH
Backlight
Threshold
This sets the threshold of where the backlight turns from amber
to red for high temperature.
Default is Off. Options are Off, then 0 to 100 % in 1 % steps.
39
Amber CO2
Backlight
Threshold
This sets the threshold of where the backlight turns from green to
amber for high carbon dioxide.
Default is Off. Options are Off, then 0 to 2000 ppm in 50ppm
steps.
40
Red CO2
Backlight
Threshold
This sets the threshold of where the backlight turns from amber
to red for high carbon dioxide.
Default is Off. Options are Off, then 0 to 2000 ppm in 50ppm
steps.
Page 20
41
Communication
Protocol
The
monitor
has
an
isolated RS
-
485
communications
capability.
You can select ModBus RTU or BACnet MSTP communications
protocol. The full stop in the temperature display will flash if
communications are running.
Default is 0 = Modbus. Options are 0 = Modbus.
1 = BACnet.
42
Communications
Speed
This
option
permits you to define the
communications
speed
for the selected communications protocol.
Default is dependent on protocol selected.
43
Communications
Parity
Communications protocols require a parity
to be set.
Default is dependent on protocol selected.
Options are 0 = None. 1 = Odd. 2 = Even.
44
Communications
Address
This setting defines the
communications
address
on the
network as used by the monitor.
Default is 7. Adjustments are 1 to 127.
45
CO2 Sensor
Response speed
The NDIR sensor fitted to the
monitor
can respond to changing
CO2 levels very rapidly. If the sensor is in a location where it is
very close to people, exhaled breath directly onto the sensor
can cause rapid spikes in CO2 readings which may not be
typical of general Indoor Air Quality levels.
Default is
2
.
Adjustments are 1
,
2 & 3 with 3 being slowest.
46
Air Quality
Display
The LCD will either
display
the air quality or can be turned
off.
On = Display Air Quality and Off = No Air Quality Display.
Factory default is Off.

Page 21
r
Reset
Setting this value to 1 then exiting the installer menu will
factory reset the monitor.
Typical Wiring Examples
The following contains wiring examples that may be helpful in setting up the monitor for
your specific application.
These wiring examples may require adjusting various options in the Installer menu. For
example, if the volt free relay is used to control a 24V power open / closed damper based
on CO2 levels, you must activate and define the CO2 Relay Alarm on page 13.
In this example a standard Variable
Speed Drive is being controled
with the CO2 0-10V output. The
Installer menu permits you to scale
the 0-10V output to match your
requirements such as output 0V at
450ppm and output 10V at
800ppm.
Page 22
In this example the CO2 and RH is
controlling the VSD with a high
select. Both the CO2 and RH
outputs are individually scalable so
the CO2 range can be 450ppm to
1,000ppm and the RH range can be
75% to 100%. Also, the RH output
can be limited to 7V max if
required.
Whether you wish to control a
Variable Speed Drive or a
modulating damper the wiring and
setup are the same. You can also
mix the devices you wish to
control with the three 0-10V
outputs. All three outputs can be
individually scaled.

Page 23
An open/close or an off/on output
can be controlled by the monitor
using the volt free relay provided.
The relay threshold can be
individually adjusted for each
sensor. (30V @ 1A max)
Active Ventilation Function
By fitting an outside air sensor, the
monitor can bring in fresh air to
improve room air quality if the
outside air temperature is suitable.
To use this function, you must first
fit an outside air temperature
sensor such as the RS-01/2 or RS1D
to the monitor T1 &T2 terminals.
Page 24
In the Installer menu you must
activate the Active Ventilation
function by setting the inside and
outside air temperature
thresholds (page 15 explains this)
and defining the active ventilation
output options. Once you have
completed these three steps the
letter “A” will be shown the in the
lower right corner of the LCD to
confirm the Active Ventilation
function is active.
If selected in the Active Ventilation options menu, the monitor will modulate the
temperature 0-10V output so that the output is at the maximum voltage set when the
room temperature is 1 degree above the inside temperature setpoint. If introducing
outside air the icon “A” will flash on the LCD. Tapping the “A” icon will briefly show the
outside air temperature.
Should you wish, you can also have the volt free relay used for active ventilation by
selecting it in the Active Ventilation Output options menu.

Page 25
If you would like, you can have
both the temperature 0-10V output
and volt free relay used for
advanced ventilation. In the Active
Ventilation Output options menu
settings select both relay and temp
0-10 (option 3). This permits you to
open the fresh air damper and turn
a fan on for example if outside air is
suitable.
This function runs in parallel to any
alarm function using these same
output(s).
The Advanced Ventilation option is
independent of the alarm and
functions of the monitor. This function will not sound any audible alarm or impact the
LCD color. The letter “A” will simply flash in the lower right corner of the LCD to show the
function is running.
Page 26
Specifications
Power 12 to 30V AC or DC
Relay Output 30V AC/DC @ 1A Max
Touch Method “XY” Resistive
Back Light Multicolor LED (Green, Red, Amber)
Back Light Life 40,000 Hours to Half Intensity
Operating Temperature 23°F To 122°F
Operating RH 0 To 95% (Non-Condensing)
0-10V Outputs 5ma Max
Temperature Sensor Range -4 - +122F
Temp Sensor Accuracy +/- 3% at 77°F
RH Sensor Range 0 to 95% RH
RH Sensor Accuracy +/-3% at 77°F (30% to 80% RH)
CO2 Sensor Range 0-2000ppm
CO2 Sensor Accuracy +/- 40ppm at 77°F
Warranty 3 Years RTB
Approvals CE & Ctick
Communications Modbus RTU 4.8 / 9.6 / 19.2 / 38.4k
BACnet MSTP 38.4 to 512k
Size 4.5” W x 4.125” H x 1” D

Page 27 Page 28
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