Indoor Fan Blower; Outdoor Axial Fan - Lennox BAC 030 SNM 3M Installation, Operating And Maintenance Manual

SERVICE DIAGNOSTIC
Refrigeration (cont'd)
Fault
HP problems and HP cut outs
Strong variations of pressure
( 2 to 3 bar) expansion valve
"hunting"
Very high discharge temperature,
High amps measured at
compressor

Indoor fan blower

Fault
High amps on action fan motor
High amps on reaction fan motor
Unstable running and high
vibration

Outdoor axial fan

Fault
Heat pump mode: circuit breaker
open
• 62 •
Possible cause and symptoms
Moisture or contaminants in the system
Condenser coil is obstructed
Recycled hot air
Incorrect adjustment of the expansion valve
Low refrigerant charge
Filter drier obstructed with gas bubbles at the
expansion valve inlet
Moisture in the system
Very high superheat, very hot compressor
Four way reversing valve possibly blocked,
abnormal noise from the valve, low LP and
increasing HP
Possible cause and symptoms
Pressure drop in the ducting installation too
low.
Pressure drop in the ducting installation too
high.
Fan jumping from one operating point to the
other
Possible cause and symptoms
High amps due to a low voltage from the main
supply
High amps due to freezing of the coil
FLEXY™: water ingress in the motor
connection box.
Solution
If the circuit pressure is higher (<1 bar) than the saturated
pressure corresponding to the measured outdoor temperature,
there is possibility that some contaminants are present in the
system.
Reclaim the refrigerant, and vacuum the circuit (ensure very
low and slow vacuum for R410A)
Recharge the unit
Check the condenser coil and clean is necessary
Check clearance around the condenser
Refer to LP problems and LP cut out section
Reduce the superheat on the electronic valve.
Check the pressure drop on the fi lter drier in the suction line
Check operation of the valve by going through cycle
inversions. Change if necessary.
Refer to LP problems
Solution
Reduce the rotation speed of the fan
Read the airfl ow and pressure and compare with the
specifi cation from customer.
Reduce the rotation speed of the fan
Read the airfl ow and pressure and compare with the
specifi cation from customer.
Change rotation speed of the fan.
Solution
Check the voltage drop when all components are running.
Change the circuit breaker for one with a higher rating.
Check the adjustable amps on the motor starter.
Adjust the defrost cycle set points.
Change the component
BALTIC-IOM-0412-E / Service manual