Lennox FLEXY II Series Installation, Operating And Maintenance page 94

MAINTENANCE DIAGNOSTIC
HP PROBLEMS AND
HP CUT OUTS
Strong v ariations of
pressure ( 2 to 3 bar)
Thermostatic
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 v ibration
OUTDOOR AXI AL FAN
FAULT
Heat Pump mode:
Circuit breaker open
IOM – FLEXY II – 1007 – E
Moisture or contaminants in the system
Condenser coil is obstructed
Recycled Hot Air
Incorrect adjustment of the expansion valv e
Low ref rigerant charge
Filter drier obstructed with gas bubbles at the
expansion valv e inlet
Moisture in the system
Very high superheat, very hot compressor
Four Way reversing v alve possibly blocked,
abnormal noise f rom the valv e, low LP and
increasing HP
POSSIBLE CAUSE AND SYMPTO MS
Pressure drop in the ducting installation too low.
Pressure drop in the ducting installation too high.
Fan jumping f rom one operating point to the
other
POSSIBLE CAUSE AND SYMPTO MS
High Amps due to a low voltage f rom the main
supply
High amps due to f reezing of the coil
Flexy: Water ingress in the motor connection
box.
If the circuit pressure is higher (<1bar) than the
saturated pressure corresponding to the
measured outdoor temperature, there is
possibility that some contaminants are present in
the system.
Reclaim the ref rigerant, and vacuum the circuit
(Ensure v ery low and slow vacuum for R407c)
Recharge the unit
Check the condenser coil and clean is necessary
Check clearance around the condenser
Ref er to LP problems and LP cut out section
Open the superheat adjustment on the expansion
v alve.
Check the pressure drop on the filter drier in the
suction line
Check operation of the v alve by going through
cy cle inv ersions. Change if necessary.
Ref er to LP problems
SOLUTION
Reduce the rotation speed of the f an
Measure and estimate the airflow and pressure
and compare with the specification from
customer.
Reduce the rotation speed of the f an
Measure and estimate the airflow and pressure
and compare with the specification from
customer.
Change rotation speed of the fan.
SOLUTION
Check the v oltage drop when all components are
running.
Change the circuit breaker f or one with a higher
rating.
Check the adjustable amps on the motor starter.
Adjust the defrost cycle set points.
Change the component
Page 92