50
AWR MTD - AWR MTD/B
GB 01/2009
TROUBLESHOOTING
A
I
No voltage
Supply voltage too low
Switch QF1 in OFF position
Remote switch (if featured) in OFF position
Control panel set to OFF
Main switch QS1 in OFF
Compressor thermal overload switch OFF
Check presence of voltage
Check safety systems upstream of
the appliance
Check power line
Switch ON
Contactor coil faulty
HSW11 controller fault
Start-up capacitor faulty (if featured)
Compressor faulty
Reversed phases (three-phase units only)
Replace the component
Check
Replace the component
Check
Check
Check
Protection devices trip
and shut down the com-
pressor
Excessive discharge pressure
Low suction pressure
Low voltage
Electrical connections not sufficiently tight
Operation outside permitted limits
Faulty operation of pressure switches
Check supply voltage
Check electrical insulation of
windings
Thermal protector tripped
Insufficient capacity
Insufficient refrigerant
Sizing of unit
Operation outside recommended limits
Noise and vibrations
Contact between metal bodies
Repair
Weak foundations
Tighten screws
Loose screws
Compressor noisy
Liquid returning to compressor
Inadequate fastening
Reverse one phase
Reversed phases (three-phase units only)
The heat pump doesn’t
start
FAULT
CAUSE
SOLUTION
