103 of 222 pages
Operating and service manual
306
High press switch
Warning
Description
High pressure switch is active
Cause
Discharge pressure is too high and the high pressure switch off
Trouble
shooting
Possible causes:
•
High pressure due to
−
Ambient temperature is over spec. limit +50°C (+122°F)
−
Manual valve after compressor closed
−
HP pipe damaged
−
Condenser fan motor is not running
−
Condenser blocked
•
Fuse F6 blown
•
High pressure switch or cable is defective
•
Wrong pressure transmitter in relation to controller settings
•
Pressure transmitter defect
•
X1 cable is defect
•
Controller PCB defective
Accompanied alarms:
•
AL 500 may be active alarm AL 604 may be or get active.
Trouble shooting:
1) The unit uses cooling refrigerant R134A and it is very difficult to operate at
temperatures above specification. The unit needs cooler surroundings, better
ventilation or water cooling.
2) If the pressure rises very quickly after start of the compressor, check that the valve
after the compressor (discharge side) is not closed or only partially open. Make sure
valve is fully open.
3) Check that there are no damages to the pipes after the compressor. Repair if they
are damaged and check cooling liquid level (R134A).
4) Check that there are no alarm for the condenser fan motor, AL 402, AL 426 and that,
the fan is rotating and that the condenser is not blocked for airflow.
5) If condenser is blocked, clean the condenser to secure cludding and dirt are
removed.
6) If alarm AL 500 ‘FC missing’ is also active, the fuse F6 inside in the control cabinet is
most likely blown. Replace the fuse.
Disconnect the cable for high pressure switch from the connector PCB according to the
wiring schematics inside the control cabinet.
7) Measure the voltage between the two connectors for the high pressure switch on the
connector PCB. If the voltage is below 15V AC, replace the controller door.
8) Check the cable (measure the resistance in the cable). If the cable is defect, replace
cable and high pressure switch.
9) Mount the cable for the high pressure switch again. If this alarm is still active on the
display, replace the controller door.
10) Look in display to see if pressure transmitter is according to settings (see
Configuration p.48 (F08)) and set controller according to transmitter.
11) If pressure transmitter type is correct, perform troubleshooting for AL 203.
Criteria
Pressure is above high pressure switch safety limit. Cut – out: 22.5 BarE ± 0.7 Bar
(326.3 psi ± 10.2 psi), Cut – in: 15.9 BarE ± 0.7 Bar (230.6 psi ± 10.2 psi).
Controller
action
Frequency controller is stopped and unit stops
Log
X
Alarm
X
Alarm light
Off
Consequence
Unit stops
Elimination
Unit restarts after 5 min. When sensor value becomes valid, it is marked as inactive in
alarm list and may then be deleted. Value must be valid for 60 sec. to set alarm inactive.
Log data
Parm 1
Parm 2
Parm 3
Parm 4
Parm 5
Active/Inactive Pdis 6 sec
0
Psuc 6 sec FCtemp 6 sec
