Loss Of Communication With The Slave Chiller Alert; Loss Of Communication With The Master Chiller Alert; Cooler Freeze Protection Alarm; Ewt Or Lwt Thermistor Failure Alarm - Carrier AquaSnap 30MPA Series Controls, Start-Up, Operation, Service, And Troubleshooting

T203 (Loss of Communication with the Slave Chiller Alert)
— This alert will be generated if Dual Chiller Control is en-
abled, LLEN=ENBL Lead/Lag Chiller Enable (Configura-
tion RSET), the chiller has been configured to be the Master
→
Chiller MSSL=MAST Master/Slave Select (Configura-
tion RSET) and it has not established or lost communication
→
with the Slave Chiller. When this alert is generated the dual
chiller control will be disabled and the unit will operate in
stand-alone mode.
If this condition is encountered, check the following items:
• Check that the communication wiring between the two
chillers is proper and is not grounded.
• Check to be sure that both the Master and Slave Chillers
are on the same bus, CCNB CCN Bus Number (Config-
uration CCN).
→
• Check to be sure that the slave chiller address CCNA
CCN Address (Configuration
programmed in the master chiller's configuration for
slave address, SLVA Slave Address (Configura-
tion RSET).
→
• Check for power at the slave chiller. If power is not pres-
ent, this alarm will be generated.
• Check for a faulty master or slave MBB. If CCN com-
munications is not working, this alarm will be generated.
T204 (Loss of Communication with the Master Chiller
Alert) — This alert will be generated if Dual Chiller Control is
enabled, LLEN=ENBL Lead/Lag Chiller Enable (Configura-
tion RSET), the chiller has been configured to be the Slave
→
Chiller MSSL=SLVE Master/Slave Select (Configura-
tion RSET) and it has not established or lost communication
→
with the Master Chiller. When this alert is generated the dual
chiller control will be disabled and the unit will operate in
stand-alone mode.
If this condition is encountered, check the following items:
• Check that the communication wiring between the two
chillers is proper and is not grounded.
• Check to be sure that both the master and slave chillers
are on the same bus, CCNB CCN Bus Number (Config-
uration CCN).
→
• Check to be sure that the slave chiller address CCNA
CCN Address (Configuration
programmed in the master chiller's configuration for
slave address, SLVA Slave Address (Configura-
tion RSET).
→
• Check for power at the master chiller. If power is not
present, this alarm will be generated.
• Check for a faulty master or slave MBB. If CCN com-
munications is not working, this alarm will be generated.
T205 (Master and Slave Chiller with Same Address Alert)
— This alert will be generated if Dual Chiller Control is en-
abled, LLEN=ENBL Lead/Lag Chiller Enable (Configura-
tion RSET), the chiller has been configured to be the Master
→
Chiller MSSL=MAST Master/Slave Select (Configura-
tion RSET) and both the master chiller and slave chiller have
→
the same address, CCNA CCN Address (Configura-
tion CCN). When this alert is generated the dual chiller con-
→
trol will be disabled and both units, master and slave, will oper-
ate in stand-alone mode.
If this condition is encountered, check to be sure that the
Slave Chiller address CCNA CCN Address (Configura-
tion CCN) matches what is programmed in the Master
→
Chiller's configuration for slave address. SLVA Slave Address
(Configuration RSET).
→
T206 (High Leaving Chilled Water Temperature Alert) —
The criterion for this alert is checked when the unit is ON and
the total available capacity is 100%. The alert is generated
when the leaving chilled water temperature is greater than the
LCWT, High LCW Alert Limit (Configuration
the control point and the leaving chilled water temperature is
CCN) matches what is
→
CCN) matches what is
→
OPT2) plus
→
higher than it was 1 minute before the current reading. The
LCWT is a delta temperature, not an absolute value. The alert
will automatically reset when the leaving water temperature is
less than the control point, or is less than the control point plus
LCWT minus 5° F (2.8° C).
If this condition is encountered:
• Check building load.
• Check the LCWT, High LCW Alert Limit (Configura-
tion OPT2) value.
→
• Check compressor operation.
• Check water flow.
A207 (Cooler Freeze Protection Alarm) — This alarm will
be generated when the leaving water temperature is below
BR.FZ, Brine Freeze Point (Set Point Mode
this condition is encountered, the machine will enter Mode 16,
and the Chilled Water Pump relay will be energized, even if the
CPC Cooler Pump Control (Configuration Mode
OFF. If the machine is equipped with a pump, the pump will
run for a minimum of 5 minutes. The unit will be shut down or
prevented from starting.
The control will allow the machine to reset automatically if
the leaving chilled water temperature rises above the BR.FZ
Brine Freeze Point (Set Point Mode
If the alarm is generated again during the same day, it shall be a
manual reset.
If this condition is encountered, check the following items:
• Check the entering or leaving water thermistor for accu-
racy.
• Check water flow rate.
• Check for freezing conditions.
• Check the heat tape and other freeze protection means
for proper operation.
• Check glycol concentration and adjust BR.FZ accord-
ingly.
A208 (EWT or LWT Thermistor Failure Alarm) — This
alarm will be generated if the entering water temperature, EWT
Entering Fluid Temp (Run Status
leaving water temperature, LWT Leaving Fluid Temp (Run
Status VIEW) by 3° F (1.7° C) or more for 1 minute after the
→
circuit has started. When this alarm is generated the chiller is
shut down and prevented from starting. Chilled water pump is
also shut down.
If this condition is encountered, check the following items:
• Check for a correct chilled water flow.
• Check the entering and leaving water thermistors for
accuracy.
• Check to be sure the entering and leaving water thermis-
tors are correctly wired and installed in the proper
location.
A220 (Condenser Pump Interlock Failure to Close At Start-
Up Alarm) — This alarm will be generated if the unit is con-
figured for D.FL.S=ENBL Enable Cond Flow Switch (Con-
figuration OPT1) and condenser flow interlock (if used) cir-
→
cuit fails to close within 5 minutes of the condenser pump start.
When this alarm is generated the chiller is prevented from
starting or will be shut down; condenser and chilled water
pumps are shut down.
If this condition is encountered, check the following items:
• Check for a condenser pump failure.
• Check for power at the condenser pump.
• Check condenser pump control wiring
• Check condenser strainer for a restriction.
replace as necessary.
• Check the condenser water flow switch operation.
• Check condenser water flow switch wiring.
• If the unit utilizes a flow regulating valve for head pres-
sure control, consider disabling condenser flow switch
feature.
70
FRZ). When
→
OPT1) is
→
FRZ) plus 6°F (3.3°C).
→
VIEW) is less than the
→
Flush or