Carrier 48HG016, Управление, эксплуатация и устранение неисправностей

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Outdoor Fans —
The operation of the outdoor fans
depends on the on/off status and discharge pressure, measured
by the condensing temperature thermistors, of each circuit.
Depending upon these values, the “fan level” for each circuit
will be either 0, 1, or 2 as defined by Table 23. Fan level will
increment when the discharge pressure is greater than the “On”
level and decrement when the discharge pressure is less than
the “Off” level. For example, if the discharge pressure starts at
90 psig for Circuit A, the fan level for Circuit A will be 0.
When the pressure rises above 150 psig, the fan level will
change from 0 to 1. Later, if the pressure drops below 0 psig,
the fan level will return to 0. However, since the pressure can-
not drop below 0 once the circuit is level 1, it will remain at
least level 1 until the corresponding compressor is turned off.
Depending upon the fan level of each circuit, the unit will
control the three outdoor fan contactors as specified in
Table 24. If any circuit requires an outdoor fan contactor to be
ON, then it will be ON even if another circuit does not require
it to be ON. As shown in Fig. 3, OFC1 controls OFM1; OFC2
controls OFM2 (028 only), OFM3, OFM5 (028 only) and
OFM6; and OFC3 controls OFM4. For example, if the fan
levels for Circuits A and B are 0 and the fan level for Circuit C
is 1, OFC1 and OFC3 will be energized.
Economizer —
If an economizer is installed, then Econo-
mizer Equipped configuration should be set to YES (EC.EQ).
If the indoor fan is off or the building is unoccupied, the econo-
mizer position is zero. If in Occupied mode and the unit is heat-
ing or cooling and the economizer cannot provide free cooling,
the economizer position is the Economizer Min Position
(MIN.P) or the position specified by the IAQ algorithm. If in
Unoccupied mode, the position is 0% open.
In cooling, the economizer will be allowed to help with
cooling if the outdoor air temperature (OAT) is less than the
economizer high temperature lockout (ECL.H). If an enthalpy
sensor is installed, the outdoor temperature must be below the
economizer high temperature lockout temperature and en-
thalpy must be low. If the outdoor temperature is less than
economizer low temperature lockout (ECL.L), the economizer
will not provide free cooling.
If the unit is in cooling, operating under thermostat control,
Y1 = ON, and the economizer is available for cooling, the
economizer will control the supply air temperature to the low
cool set point (LCSP). When Y2 = ON, the economizer
will control the supply air temperature to high cool set point
(HCSP).
If the unit is in cooling, operating under space temperature
control, the economizer is available for cooling, and no com-
pressors are operating, the economizer will control the SAT to
either LCSP or HCSP (see Table 25). If a compressor is ON,
the economizer will try to position itself at 100%.
If at any time there is a low suction pressure problem while
the economizer is cooling, the maximum allowable economiz-
er position will be reduced. The maximum values are 50, 25
and 0% for circuits A, B and C respectively. The maximum
value will remain in effect until the compressor “in trouble”
turns off. The effective maximum economizer position must
always be higher than the current minimum position.
Table 23 — Outdoor Fan Level Transitions
Table 24 — Fan Level Control of
Outdoor Fan Contactors (1,2,3)
Table 25 — LCSP and HCSP Transitions for
Space Temperature Mode
LEGEND
SAT — Supply-Air Temperature
Indoor Air Quality (IAQ) —
On the Centurion unit,
indoor air quality (IAQ) is measured using a CO
2
sensor whose
measurements are displayed in parts per million (PPM). The
IAQ sensor can be field- or factory-installed in the return duct.
If IAQ must be measured directly in the space instead of the
unit return, a wall-mounted accessory can be field installed.
The Centurion unit’s indoor air quality algorithm modulates
the position of the economizer damper 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 (AQ.MP) while the higher is referred as Economizer
Minimum Position (MIN.P). The AQ.MP should be set to an
economizer position that brings in enough fresh air to remove
contaminants and CO
2
generated by sources other than people.
The MIN.P should be set to an economizer position that brings
in enough fresh air to remove contaminants and CO
2
generated
by all sources including people. The MIN.P value is the design
value for maximum occupancy.
The ComfortLink™ control will begin to open the damper
from the AQ.MP position when the IAQ level begins to exceed
the OAQ level by a configurable amount, which is referred to
as AQ Differential Low (AQD.L). If OAQ is not being
measured, OAQ will be assumed to equal 400 PPM. When the
differential between IAQ and OAQ reaches AQ Differential
High (AQD.H), the economizer position will be MIN.P. When
the IAQ/OAQ differential is between AQD.L and AQD.H, the
control will modulate the damper between AQ.MP and MIN.P
in a linear manner as shown in Fig. 12 below. The damper
position will never exceed the bounds specified by AQ.MP and
MIN.P during IAQ control. If the building is occupied and the
indoor fan is running and the differential between IAQ and
OAQ is less than AQD.L, the economizer will remain at
AQ.MP. The economizer will not close completely. The
damper position will be 0 when the fan is not running or the
building is unoccupied. The damper position may exceed
MIN.P in order to provide free cooling.
The ComfortLink control is configured for air quality
sensors which provide 4 mA at 0 PPM and 20 mA at
2000 PPM. If a sensor has a different range, these bounds must
be reconfigured. The values for I.4M, I.20M, O.4M and
O.20M on the display represent the PPM corresponding to
4 mA and 20 mA for IAQ and OAQ, respectively.
If OAQ exceeds the OAQ Lockout Value (OAQ.L), the
economizer will remain at AQ.MP.
FAN LEVEL
CIRCUIT (PRESSURE) (psig)
A B C
Lev1Off 0 0 0
Lev1On 150 150 150
Lev2Off 100 100 100
Lev2On 200 200 200
FAN LEVEL
CIRCUIT
A B C
0 — — —
1 1 3 1, 3
2 1, 2 2, 3 1, 2, 3
CURRENT SAT
SET POINT
COOL DEMAND
(
∆∆∆∆
F)
NEXT SAT
SET POINT
LCSP >0.5 HCSP
HCSP <0 LCSP
LCSP <–0.5 Exit Cooling