Lennox ROOFTOP FLEXY FXK 100, Installation, Operating And Maintenance

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