McQuay ALZ “B” User Manual

304 C – 02/06 D – pag. 11/16
Meaning of LED indicators in single-compressor units
LED Flashing Steady
Tandem 1 Request for tandem 1 Tandem 1 actuated
Tandem 2
Request for tandem 2
Request for tandem 1 at 100%
Tandem 2 actuated
Tandem 1 actuated at 100%
Cooling - Cooling
Heating - -
Χ100 - Value Χ100
Yellow and green LED indicators on the main board - The yellow LED indicator informs the User of the correct
operating of the unit. During normal operation it blinks every 1 second. In case of alarm condition it flashes more
rapidly (about 2 times per second). In case of LED off the unit is not supplied. The green LED indicates that
communication between unit and remote terminal is OK. In case of communication failure, the green LED turns off
(usually due to a problem with the cable or to a not good contact between the cable and its relative female
telephone connector on the main board or on the terminal).
Alarms and messages
Any time an alarm condition is detected, the controller will prompt the following actions:
• the buzzer sounds
• the alarm relay energizes
• the temperature value blinks on display
• the alarm code appears on the LCD alternatively with the temperature value.
After the alarms have been cleared either with automatic reset or by pressing the and keys simultaneously for 5s
(for alarms with manual reset), the controller will restore normal operating conditions:
• the buzzer turns off
• the alarm relay disenergizes
• the temperature value blinks no longer
• the alarm code disappears from the LCD.
If the alarm condition persists, the actions described above will be performed again.
"µchiller" has 9 alarms detected by means of external digital contacts (24Vac); such external alarms are not
detected with the unit in stand-by.
Alarm table
Type Alarm Reset Message on display
High pressure circuit 1 open manual H1
Low pressure circuit 1 open manual L1
Tandem 1 overload open automatic C1
Fan overload circuit 1 open automatic F1
Flow switch open manual FL
High pressure circuit 2 open manual H2
Low pressure circuit 2 open manual L2
Tandem 2 overload open automatic C2
Fan overload circuit 2 open automatic F2
Technical specifications
Power supply
Power supply range 24V -15%...+10% 50/60 Hz (20,4V~ 26,4 Vac)
Minimum absorbed power 25 VA
Technical specifications
Operating temperature -10 ÷ 65°C
Operating umidity 90% U.R.
Index of protections IP55

McQuay ALZ “B” Specifications

General

Brand	McQuay
Model	ALZ “B”
Category	Chiller
Language	English