Lennox BAH075DNM User Manual

MAINTENANCE DIAGNOSTIC
BALTIC R410A-IOM-0708-E Page 119
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 s
ome contaminants are present in
the system.
Reclaim the refrigerant, and vacuum the circuit
(Ensure very 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 valve
Low refrigerant charge
Strong variations of
pressure ( 2 to 3 bar)
Thermostatic
Expansion Valve
"hunting"
Filter drier ob
structed with gas bubbles at the
expansion valve inlet
Moisture in the system
Refer to LP problems and LP cut out section
Very high superheat, very hot compressor
Open the superheat adjustment on the expansion
valve.
Check the pres
sure drop on the filter drier in the
suction line
Four Way reversing valve possibly blocked,
abnormal noise from the valve, low LP and
increasing HP
Very high discharge
temperature,
High amps measured
at compressor
Check operation of the valve by going through
cycle inversions. Change if necessary.
Refer 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 fan
Measure and estimate the airflow and pressure
and compare with the sp
ecification from
customer.
High amps on reaction
Fan motor
Pressure drop in the ducting installation too high.
Reduce the rotation speed of the fan
Measure and estimate the airflow and pressure
and compare with the specification from
customer.
Unstable r
unning and
high vibration
Fan jumping from one operating point to the
other
Change rotation speed of the fan.
OUTDOOR AXIAL FAN
FAULT POSSIBLE CAUSE AND SYMPTOMS SOLUTION
High Amps due to a low voltage from the ma
in
supply
Check the voltage drop when all components are
running.
Change the circuit breaker for one with a higher
rating.
High amps due to freezing 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

Lennox BAH075DNM Specifications

General

Brand	Lennox
Model	BAH075DNM
Category	Air Conditioner
Language	English