CU/CFCU
Condensing Units
22
Condensing Units
Installation & Maintenance Manual : 6259626 IM V1.6.0 04/16
Commissioning
SYSTEM READINGS
NOTE :- The sight glass should only be used as an assistance to charging as the
charge level showing in the glass will vary according to different operating
conditions. This is especially noticeable with the heat pump units where the
system may appear to be undercharged in the heating mode.
Evaporating temperature (suction gauge) should read approximately 2°C. to 3°C. with a
room (return air temperature) of approximately 22 °C.
Condensing temperature (as read on the discharge gauge) should be in the region of 45
to 46 °C. with an external ambient temperature of 30°C (Condensing is normally 15 °C.
above ambient).
RUNNING CHECKS
Once the system has been charged, the following running checks should be carried out:-
Check the operation of the fan speed controller by observing an increase in fan speed if
the outdoor coil is temporarily partially blocked.
If the system is a heat pump option, check that the reversing valve switches over from
cooling to heating and vice-versa.
NOTE: Head pressure control also operates in heating mode by slowing down the
outdoor unit fan as the system pressure rises. This can be checked by partially
blocking the inlet grilles of the indoor unit and observing the outdoor unit fan
slowing down.
IMPORTANT
FINALLY AND MOST IMPORTANT - Fill in the commissioning sheet and return a
copy to the factory to ensure that the warranty on the unit will be valid.
ALARM DIAGNOSTIC
OPERATION
(CU./CUH.1-4)
Unit control is via a microprocessor board found inside the control panel of the unit. The
board features 4 Red LED alarm indicators to indicate specific outdoor controller alarms
which should be checked when troubleshooting.
During situations when there is more than one alarm present the LED’s will only indicate
one alarm based on a priority sequence shown below.
ALARM
Priority
Alarm Description
LED 1
LED 2
LED 3
LED 4
1
A1
– Low Pressure Fault
On
2
A2
– High Pressure Fault
On
3
A3
– Auxiliary Alarm
On
4
A4 or A5 Outdoor Fan Fault
On
On
5
T2
– Coil Sensor Fault
Flashing
1
Compressor Delay Active
Flashing
2
S1 Communications Fault
On
1
LED4 will operate independently of the other alarm LEDs and will follow its own
priority sequence, as indicated in the table.
2
LED 4 will also flicker intermittently when the controller is communicating with the
indoor board.
3
The Airedale matched indoor units can be configured to a Master/Slave function,
refer to indoor unit manuals for details.
4
Master/Slave control refers to a number of indoor units in one area being
controlled at one designated indoor unit by one command. This does not refer to
connection to a proprietary commercial BMS system.
