Airedale SmartCool 11-233kW - Manual (Page 180)

SmartCool
TM
- D Precision Air Conditioning
180
Precision Air Conditioning
Installation, Maintenance and Commissioning Manual :6877419 02/2013
Troubleshooting
FAULT POSSIBLE CAUSE REMEDY / ACTION
Suction pressure too low Low evaporator airflow. Depending on model:
Check fan motor speed set point
Flash gas (bubbles in sight glass) at expansion
valve. Investigate for refrigerant leaks, repair and re-
charge system.
Clogged filter drier (pressure / temperature drop
across it). Replace.
Obstruction in expansion valve. Inspect, clean or replace.
Suction throttle valve closed Check that the STV operates correctly and is not
stuck shut.
Condenser fan not
operating - power on Motor / fan assembly jammed. Isolate unit and check free rotation of motor / fan
assembly. If faulty - replace.
Fault at motor terminal box supply terminals. Isolate and check electrical connections are
secure.
Motor internal overheat protector tripped. Carry out continuity check at terminals “TK” in
motor terminal box. If tripped and motor hot -
check bearings. If tripped and motor cold -
replace motor.
Power supply failure. Check power supply at circuit breaker.
Wiring to motor. Check voltage at motor terminals.
Faulty motor windings / capacitor. Motor humming would indicate fault in motor or
capacitor.
Minimum speed set too low. Adjust head pressure controller to suit.
Faulty pressure sensor. Check electrical connections are secure at
controller and pressure sensor. Replace
controller and sensor (as they are matched
sets).
Faulty Controller. Link wires “line” and “load” to bypass controller.
If motor runs full speed - replace unit.
Condenser fan runs too
fast
Condenser fans runs only
slowly High ambient condition or excessive
recirculation of air around condenser coil. Check installation against design.
Minimum set speed setting incorrect. Adjust as necessary.
Incorrect pressure setting. Adjust sensor screw as necessary.
Faulty Fan Speed Controller. Replace controller and sensor (as they are
matched sets).
Faulty pressure sensor. Replace controller and sensor (as they are
matched sets).
Motor wired incorrectly. Check against wiring diagram - correct as
required.
Motor / capacitor faulty. Replace.
Troub
les
hoo
ting