27
calculated outside air CFM falls below Power Exhaust Stage1
CFM (
PE1.C
). The Power Exhaust Stage2 CFM (
Configura-
tion
ECON
PE2.C
) is not currently used on these products.
Indoor Air Quality (IAQ)
The
Comfort
Link control has the capability for several meth-
ods of demand ventilation control. Indoor air quality is typical-
ly measured using a CO
2
sensor whose measurements are dis-
played in parts per million (ppm). Outdoor air quality may be
measured with a CO
2
sensor for indoor-outdoor differential de-
mand ventilation control, or with other sensor types for the out-
door air lockout function. The factory-installed indoor air qual-
ity CO
2
sensor is mounted in the return section. A field-in-
stalled indoor air quality CO
2
sensor may be mounted in the
return duct or directly in the occupied space, per job require-
ments. The indoor air quality modes of operation can be affect-
ed by configurations for indoor air quality sensor (
Configura-
tion
AIR.Q
IA.CF
), indoor air quality switch (
Configura-
tion
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
Comfort
Link control is configured for indoor air quality
sensors which provide 4 to 20 mA signal for 0 to 2000 ppm
CO
2
. If the sensor being used has a different range, the ppm
display range must be reconfigured by entering new values for
the IAQ Sensor Value at 4mA (
Configura-
tion
AIR.Q
I.4M
) and IAQ Sensor Value at 20mA (
Config-
uration
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 Econ Min at Max Fan Speed (
Con-
figuration
ECON
MP.MX
) when the fan is at Supply Fan
Maximum Speed (
Configuration
I.FAN
FS.MX
) and the
damper position will vary at other fan speeds as described in
the Economizer section, when the space is occupied and the in-
door fan is on.
IA.CF = 1 (DCV)
When
IA.CF = 1
, the IAQ algorithm is set for Demand Con-
trolled Ventilation (DCV). During DCV, the damper modulates
between two user configurations depending upon the relation-
ship between the Indoor Air Quality (IAQ) and the Outdoor
Air Quality (OAQ).
The lower of these two positions is referred to as the Econo
Min IAQ Position (
Configuration
AIR.Q
AQ.MN
), while
the higher is referred to as the Econ Min at Max Fan Speed
(
Configuration
ECON
MP.MX
). The Econo Min IAQ Po-
sition (
AQ.MN
) should be set to an economizer position that
brings in enough fresh air to remove contaminates and CO
2
generated by sources other than people. The Econ Min at Max
Fan Speed (
MP.MX
) should be set to an economizer position
that brings in fresh air to remove contaminates and CO
2
gener-
ated by all sources including people when the indoor fan is op-
erating at the Supply Fan Maximum Speed (
Configura-
tion
I.FAN
FS.MX
). The Econ Min at Max Fan Speed
(
MP.MX
) value is the design value for maximum occupancy.
The
Comfort
Link controls will begin to open the damper from
the Econo Min IAQ Position (
AQ.MN
) position when the IAQ
level begins to exceed the Outdoor Air Quality (OAQ) level by
a configurable amount. This amount is referred to as AQ Dif-
ferential Low (
Configuration
AIR.Q
AQD.L
). When the
differential between IAQ and OAQ reaches AQ Differential
High (
Configuration
AIR.Q
AQD.H
), the economizer po-
sition will be at the Econ Min at Max Fan Speed (
MP.MX
)
when the indoor fan speed is at Supply Fan Maximum Speed
(
FS.MX
). When the IAQ/OAQ differential is between AQ Dif-
ferential Low (
AQD.L
) and AQ Differential High (
AQD.H
),
the control will modulate the damper between Econ Min at
Max Fan Speed (
MP.MX
) and Econo Min IAQ Position
(
AQ.MN
) in a linear manner as shown in Fig. 8. At other fan
speeds the economizer damper will operate in the shaded area
between the two economizer position curves but at the actual
fan speed as indicated by Commanded Fan Speed (
Out-
puts
FANS
F.SPD
Fig. 8 — Economizer Minimum Position
IA.CF = 2 (Override IAQ)
When IA.CF = 2, the IAQ algorithm maintains the damper at
Econ Min at Max Fan Speed (
Configura-
tion
ECON
MP.MX
) when the indoor fan speed is at Sup-
ply Fan Maximum Speed (
Configuration
I.FAN
FS.MX
)
or along the curve on Fig. 8 when the indoor fan speed is at the
Commanded Fan Speed (
Outputs
FANS
F.SPD
) until the
override condition triggers. The override triggers when the
IAQ/OAQ differential is greater than AQ Differential High
(
Configuration
AIR.Q
AQD.H
). The IAQ Override Posi-
tion (
Configuration
AIR.Q
OVR.P
) sets the damper posi-
tion during override. The economizer damper will return to the
Econ Min at Max Fan Speed (
MP.MX
) or
MP.MX
curve at oth-
er fan speeds when the IAQ/OAQ differential is less than the
AQ Differential Low (
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 IAQ Ana-
log Fan Config (
Configuration
AIR.Q
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 unoccu-
pied, the economizer position will be zero. The damper posi-
tion may exceed Econ Min at Max Fan Speed (
MP.MX
) or IAQ
Override Position (
OVR.P
) to provide economizer cooling.
IA.CF = 3 (Control Minimum Position)
When
IA.CF = 3
, an external 4 to 20 mA source is used to set
the minimum position. The 4mA signal corresponds to 0% and
the 20 mA signal corresponds to 100%. In this mode, configu-
rations such as Econ Min at Max Fan Speed (
Configura-
tion
ECON
MP.MX
), Econo Min IAQ Position (
Configu-
ration
AIR.Q
AQ.MN
) and the economizer minimum posi-
tion and DCV minimum position curves in Fig. 7 and 8 are not
used. If the indoor fan is not operating, the economizer position
will be zero. The damper position may exceed the economizer
minimum position to provide economizer cooling.
IAQ (SWITCH INPUT)
Indoor air quality can also be measured using a switch input. For
the purpose of specifying the type of switch input, low CO
2
lev-
els are considered normal. The IAQ switch input is defined by
VENTILATION FOR PEOPLE
VENTILATION FOR SOURCES
INCREASING VENTILA
TION
ECON MIN
AT MAX
FANSPEED
POSITION
(MP.MX)
MINIMUM
IAQ
DAMPER
POSITION
(AQ.MN)
O
C
E
D
I
S
T
U
O
/
E
D
I
S
N
I
0
0
7
0
0
1
2
DIFFERENTIAL
AQ
DIFFERENTIAL
LOW
(AQD.L)
AQ
DIFFERENTIAL
HIGH
(AQD.H)
Содержание /50HC 04-28
Страница 61: ...61 Fig 21 Saturated Condensing Temperature Thermistor Location 48 50HC 14 SCT B SCT A CIRCUIT B CIRCUIT A ...
Страница 69: ...69 Fig 24 Typical Control Diagram for 48HC 04 14 Units 48HC 08 09 shown ...
Страница 70: ...70 Fig 25 Typical Power Diagram for 48HC 04 14 Units 48HC 08 09 shown ...
Страница 71: ...71 Fig 26 Typical Control Diagram for 50HC 04 14 Units 50HC 14 shown ...
Страница 72: ...72 Fig 27 Typical Power Diagram for 50HC 04 14 Units 50HC 14 Non Humidi MiZer shown ...
Страница 73: ...73 Fig 28 Typical Control Diagram 48HC 17 28 Units ...
Страница 74: ...74 Fig 29 Typical Control Diagram 50HC 17 28 Units ...
Страница 75: ...75 Fig 30 Typical Humid MiZer Power Diagram and Component Arrangement 48 50HC 17 28 Units ...
Страница 76: ...76 Fig 31 Typical Non Humid MiZer Power Diagram and Component Arrangement 48 50HC 17 28 Units ...
Страница 89: ...89 Fig 42 Modulating ERV Wiring Schematic ...
Страница 90: ...90 Fig 43 EnergyX ERV Control Box Component Layouts ...
Страница 101: ...101 Fig 59 Exhaust Fan Assembly Removal Exhaust Fan Assembly ...
Страница 141: ......