Indoor Air Quality (Iaq) - Carrier 48PG03-16 Controls, Start-Up, Operation, Service And Troubleshooting Instructions

DEMAND AND MODE
Space Circuit Circuit
Humidity Cooling Mode
Demand
— — No power
Low No Off
Low Yes Cool
High Yes Reheat1
High No Reheat2
*Note: One CRC state for all circuits per space humidity.
Air Baffles
The 48/50PG units with Humidi-MiZer option are equipped with
Motormaster® control to maintain adequate discharge pressure
for proper unit operation during low ambient operation. This
becomes especially critical in the Reheat2 mode of operation.
Wind could have a detrimental effect depending on the
orientation and the expected design latent load of the space. If the
unit is oriented with the vertical condenser coil toward the
prevailing wind, then the field-fabricated wind baffles are
required. If the unit is not oriented as described above, but there is
expected long operational periods in the Reheat2 mode, then the
field-fabricated wind baffles are recommended. See Fig. 15 for
dimensions of the field-fabricated wind baffles.

Indoor Air Quality (IAQ)

The ComfortLink™ control has the capability for several methods
of demand ventilation control. Indoor air quality is typically
measured using a CO sensor whose measurements are displayed
2
in parts per million (ppm). Outdoor air quality may be measured
with a CO sensor for indoor-outdoor differential demand
2
ventilation control, or with other sensor types for the outdoor air
lockout function. The factory-installed indoor air quality CO
sensor is mounted in the return section. A field-installed indoor
air quality CO sensor may be mounted in the return or directly
2
in the occupied space, per job requirements. The indoor air
quality modes of operation can be affected by configurations for
indoor air quality sensor (Configuration "AIR.Q"IA.CF), indoor
air quality switch (Configuration "AIR.Q"II.CF), outdoor air
quality sensor (Configuration "AIR.Q"OA.CF) and other
related fan and limit configurations as described below.
IAQ (Analog Input)
The ComfortLink control is configured for indoor air quality
sensors which provide 4 to 20 mA for 0 to 2000 ppm. If a sensor
has a different range, the ppm display range must be reconfigured
by entering new values for Configuration→AIR.Q→I.4M and
Configuration→AIR.Q→I.20M.
IA.CF = 0 (No IAQ)
IA.CF = 0 signifies that there is no IAQ sensor installed. The
damper will operate at the Configuration→AIR.Q→EC.MN
position when the space is occupied and the indoor fan is on.
Table 91—Control Modes with Humidi-MiZer System
Output and Valve States versus Circuit Mode .x = Circuit A, B, or C identifier
OUTPUTS
Indoor Fan Circuit
(IDF) Compressor
(CMP .x)
OFF OFF
Per OFF
ventilation
control
ON ON
ON ON
ON ON
Cooling- Reheat2 CV.x Valve
Reheat Valve
Control (RH2.x)
(CRC)*
OFF OFF Off (open)
OFF OFF Off (open)
OFF OFF Off (open)
ON OFF On (closed)
ON ON On (closed)
IA.CF = 1 (DCV)
When IA.CF = 1, the IAQ algorithm is set for Demand Control
Ventilation (DCV). During DCV, the damper modulates between
two user configurations depending upon the relationship between
the IAQ and the Outdoor Air Quality (OAQ). The lower of these
two positions is referred to as the Minimum IAQ Damper
Position (Configuration →AIR.Q→AQ.MN) while the higher is
referred to as Economizer Minimum Position (EC.MN). The
AQ.MN should be set to an economizer position that brings in
enough fresh air to remove contaminants and CO
sources other than people. The EC.MN should be set to an
economizer position that brings in enough fresh air to remove
contaminants and CO
The EC.MN value is the design value for maximum occupancy.
The ComfortLink control will begin to open the damper from the
AQ.MN position when the IAQ level begins to exceed the
Outdoor Air Quality (OAQ) level by a configurable amount. This
amount is referred
(Configuration→AIR.Q→AQD.L).
between IAQ and OAQ reaches AQ Differential High
(Configuration→AIR.Q→AQD.H), the economizer position will
2
be EC.MN. When the IAQ/OAQ differential is between AQD.L
and AQD.H, the control will modulate the damper between
AQ.MN and EC.MN in a linear manner as shown in Fig. 16. The
damper position will never exceed the bounds specified by
AQ.MN and EC.MN during IAQ control.
IA.CF = 2 (Override IAQ)
When IA.CF = 2, the IAQ algorithm maintains the damper at
Configuration →AIR.Q→EC.MN until the override condition
triggers. The override triggers when the IAQ/OAQ differential is
greater than Configuration→AIR.Q→AQD.H. The override
Configuration→AIR.Q→OVR.P
position is
Override Position). The economizer position will return to
EC.MN
when the IAQ/OAQ
Configuration →AIR.Q→AQD.L.
The Override algorithm will operate whenever the building is
occupied and the indoor fan is operating or whenever the IAQ
algorithm has caused the indoor fan to operate. The
configuration IA.FN determines whether or not the IAQ
algorithm can turn on the indoor fan.
If the indoor fan is not operating, the economizer position will be
zero. If the override is not active and the building is unoccupied,
the economizer position will be zero. The damper position may
Configuration→AIR.Q
exceed
Configuration→AIR.Q→OVR.P to provide economizer cooling.
72
VALVES
RH1.x Valve RH2.x Valve
2-way 2-way
Off (open) Off (closed)
On (closed) Off (closed)
On (closed) Off (closed)
Off (open) Off (closed)
Off (open) On (open)
generated by
2
generated by all sources including people.
2
to as AQ Differential
When the
(Economizer
differential is less than
→EC.MN
2-way
Low
differential
or