© 2018 nVent
89091001
- 6 -
Alarm
Mnemonic
Description
Cause
Result
Alarm Relay
tP
General Alarm
Door open and/or smoke detected
Unit turns OFF for duration
of alarm
Relay Contact closed
LA
High Pressure Warning
MALF high pressure switch opens
(see note 3 below)
No effect on function
N/A
LP
Low Pressure Alarm
Low pressure switch open (see note
4 below)
No effect on function
Relay Contact closed
E1
Air Inlet Temperature Sensor
Alarm
Sensor failure
See note 1 below
Relay Contact closed
E2
Air Outlet Temperature
Sensor Alarm
Sensor failure
See note 2 below
Relay Contact closed
Ht
High Temperature Alarm,
default = 55°C
Air inlet temperature greater than
55°C
No effect on function
Relay Contact closed
Lt
Low Temperature Alarm,
default = 14°C
Air inlet temperature less than 14°C
No effect on function
N/A
A1
Frost Alarm
Air outlet temperature less than or
equal to -1.0°C
Compressor and Condenser
fan OFF for duration of alarm
Relay Contact closed
HP/HP1
High Pressure Serious Alarm
High pressure switch open (see
note 5 below)
Unit turns OFF for duration
of alarm
Relay Contact closed
LC
Lost Communication Alarm
The Master cannot communicate
with any Slave, or the Slave cannot
communicate with the Master
No effect on function. Unit
will enter standalone mode
N/A
LC1
Lost Communication Alarm
The Master cannot communicate
with one of the Slaves
No effect on function. Unit
will enter standalone mode
N/A
NOTE 1: Air inlet temperature sensor will default to air outlet temperature sensor. Cooling setpoint
default to 10°C.
NOTE 2: Unit continues to operate without evaporator freeze protection.
NOTE 3: The MALF high pressure switch is optional.
NOTE 4: The Low Pressure switch is optional.
NOTE 5: The High Pressure (HP) or High Pressure Serious (HP1) switch is optional.
MASTER-SLAVE CAPABILTY (OPTIONAL)
The Master-Slave capability is included as standard and can accommodate up to four (4) air conditioners in a single cabinet.
In the Master-Slave operating mode, there is a delay period of 20 seconds between startup of each unit during the startup.
For example, the master unit number 1 starts first, unit number 2 will start after 20 seconds, followed by unit 3 and another
20 seconds, and so on.
Note the controller default operating mode is single or standalone. To initiate the Master-Slave operating mode,
parameters H24 and H25 require reconfiguration as described below. TLAN communication and Door Open cables
are also required to interconnect the air conditioners.
•
Connect the door open and/or smoke detected harness to the DS1 and DS2 terminals on the enclosure side of the air conditioner
unit in parallel. The maximum length of the door switch harness between two air conditioners is 3.33 meter (10 feet). This
harness is NOT included with the Master-Slave option. It is offered separately as an accessory.
•
Connect the TLAN harness to the MS1 and MS2 terminals on the enclosure side of the air conditioner unit in parallel. The
maximum length of the TLAN communication cable is 10 meters (30 feet) and 3.33 meters (10 feet) between the two air
conditioners. This harness is NOT included with Master-Slave option. It is offered separately as an accessory.
•
Select one of the units in the group to be the master unit. This is indicated unit number 1
•
Select the slave units, numbers 2, 3 and 4 in sequence.
ALARM PARAMETERS
Parameter
Description
Default Value
Range
h24
Device unit ID
0
0 to 4
h25
Number of units
4
2 to 4
NOTE 6: To initiate Master-Slave operating mode, set parameter h24 (device unit ID) of master unit to 1. Set
parameter h24 of slave units as applicable. Set parameter h24 (unit number 2) to 2, set parameter h24 (unit number
3) to 3, and set parameter h24 (unit number 4) to 4.
NOTE 7: Set parameter h25 (number of units) of each unit to the same value, for example, h25 = 2 if only two units
are connected in a group, h25 = 3 if three units are in a group and h25 = 4 if four units are in a group.
