35
CSB B1 Feedback Alarm (
CS.B1
) — This configuration is
used to enable or disable the compressor B1 feedback alarm.
This configuration must be enabled at all times.
CSB B2 Feedback Alarm (
CS.B2
) — This configuration is
used to enable or disable the compressor B2 feedback alarm.
This configuration must be enabled at all times.
Reverse Rotation Verified? (
REV.R
) — If this configuration
is set to NO, then after a power up, in the normal run mode, the
control will check the suction pressure on the first circuit that is
energized after 5 seconds of run time. If the control does not
see a sufficient decrease in suction pressure over the first 5
seconds, mechanical cooling will be shut down, and an alarm
will be generated (A140). This alarm requires a manual reset.
If the unit is in the Service Test mode, the test will be
performed any time a compressor is energized.
Once it has been verified that power to the rooftop and
compressors has been applied correctly and the compressors
start up normally, this configuration can be set to YES in order
to prevent the reverse rotation check from occurring.
High SST Alert Delay Time (
H.SST
) — This option allows
the high saturated suction temperature alert timing delay to be
adjusted.
COMPRESSOR SAFETIES — The 48/50A Series units with
Comfort
Link controls include a compressor protection board
(CSB) that protects the operation of each of the compressors.
These boards sense the presence or absence of current to each
compressor.
If there is a command for a compressor to run and there is
no current, then one of the following safeties or conditions
have turned the compressor off:
• Compressor overcurrent — Smaller compressors have
internal line breaks and larger compressors have a dedicated
circuit breaker for overcurrent protection.
• Compressor short circuit — the compressor circuit breaker
that provides short circuit protection has tripped then there
will not be current.
• Compressor motor over temperature — the internal line-
break or over temperature switch has opened.
• High-pressure switch trip — High-pressure switch has
opened.
Alarms will also occur if the current sensor board malfunc-
tions or is not properly connected to its assigned digital input. If
the compressor is commanded OFF and the Current Sensor
reads ON, an alert is generated. This will indicate that a com-
pressor contactor has failed closed. In this case, a special mode
“Compressor Stuck on Control” will be enabled and all other
compressors will be turned off and an alarm enabled to indicate
that service is required. Indoor and outdoor fans will continue
to operate. The first outdoor fan stage is turned on immediately.
The second fan stage will turn on when outdoor-air
temperature (OAT) rises above 75 F or the highest active cir-
cuit saturated condensing temperature (SCT) rises above the
HPSP and remains on until the condition is repaired regardless
of the OAT and SCT values.
Any time the alert occurs, a strike is called out on the affect-
ed compressor. If three successive strikes occur the compressor
will be locked out requiring a manual reset or power reset of
the circuit board. The clearing of strikes during compressor op-
eration is a combination of 3 complete cycles or 15 continuous
minutes of run time operation. If there are one or two strikes on
the compressor and three short cycles (ON-OFF, ON-OFF,
ON-OFF) less than 15 minutes each occur, the strikes are reset
to zero for the affected compressor. If the compressor turns on
and runs for 15 minutes straight with no compressor failure, the
compressor strikes are cleared.
Additionally, some units contain Copeland compressors
equipped with advanced scroll temperature protection (ASTP).
A label located above the terminal box identifies Copeland
Scroll compressor models that contain this technology. See
Fig. 5. Advanced scroll temperature protection is a form of in-
ternal discharge temperature protection that unloads the scroll
compressor when the internal temperature reaches approxi-
mately 300 F. At this temperature, an internal bi-metal disk
valve opens and causes the scroll elements to separate, which
stops compression. Suction and discharge pressures balance
while the motor continues to run. The longer the compressor
runs unloaded, the longer it must cool before the bi-metal disk
resets. See Fig. 6.
To manually reset ASTP, the compressor should be stopped
and allowed to cool. If the compressor is not stopped, the motor
will run until the motor protector trips, which occurs up to
90 minutes later. Advanced scroll temperature protection will
reset automatically before the motor protector resets, which
may take up to 2 hours.
COMPRESSOR TIME GUARDS — The control will not al-
low any output relay to come on within 3 seconds of any other
output relay. For outputs connected to the compressors, the con-
trol will use a Compressor Minimum OFF Time of 2 minutes, a
Compressor Minimum ON Time of 3 minutes and a Minimum
Delay before turning on another compressor of 10 seconds.
COOL MODE SELECTION PROCESS — The A Series
Comfort
Link controls offer three distinct methods by which it
may select a cooling mode.
1. Thermostat (
C.TYP
= 3 and 4): The thermostat does not
depend upon the state of occupancy and the modes are
called out directly by the discrete inputs from the thermo-
stat (
Inputs
STAT
Y1
and
Y2
).
2. Occupied VAV cooling types (
C.TYP
= 1 and 2) are
called out in the occupied period (
Operating Modes
MODE
OCC
= ON).
3. Unoccupied VAV cooling types (
C.TYP
= 1 and 2) are
called out in the unoccupied period (
Operating
Modes
MODE
OCC
= OFF). They are also used for
space sensor control types (
C.TYP
= 5 and 6) in both
the occupied and unoccupied periods.
Fig. 5 — Advanced Scroll Temperature
0
10
20
30
40
50
60
70
80
90
100
110
120
0
10
20
30
40
50
60
70
80
90
Recommended Cooling
Time
(Min
utes)
Compressor Unloaded Run Time (Minutes)
*Times are approximate.
NOTE: Various factors, including high humidity, high ambient tem-
perature, and the presence of a sound blanket will increase cool-
down times.
Fig. 6 — Recommended Minimum Cool-Down
Time After Compressor is Stopped*
Содержание Carrier Weathermaker 48A2
Страница 105: ...105 Fig 20 Typical Main Control Box Wiring Schematic 48 50A2 A3 A4 A5 Units...
Страница 106: ...106 Fig 21 Typical Auxiliary Control Box Wiring Schematic...
Страница 107: ...107 Fig 22 Typical 2 Stage Gas Heat Wiring Schematic Size 060 Units Shown a48 8357...
Страница 108: ...108 TO NEXT PAGE Fig 23 Typical Staged Gas Heat Wiring Schematic Size 060 Units Shown A48 7296...
Страница 109: ...109 Fig 23 Typical Staged Gas Heat Wiring Schematic Size 060 Units Shown cont A48 8358...
Страница 110: ...110 Fig 24 Typical Electric Heat Control Schematic 50 Series Size 060 Units Shown a50 8228...
Страница 111: ...111 Fig 25 Typical Power Schematic 48 50A2 A3 A4 A5 060 Unit Shown...
Страница 112: ...112 Fig 26 Typical Low Ambient Controls Option Wiring...
Страница 113: ...113 Fig 27 Typical Small Chassis Component Location Size 020 035 Units...
Страница 114: ...114 Fig 28 Typical Large Chassis Component Locations Size 040 060 Units...
Страница 118: ...118 Fig 30 Economizer Control Board ECB1 and VAV Control Board ECB2 A48 7706...
Страница 142: ...142 A48 3733 Fig 56 Main Burner Removal...
Страница 176: ...176 APPENDIX C VFD INFORMATION cont Fig F Internal Enclosure Fan Replacement A48 7716...