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Lubrication, Troubleshooting - heating system, Troubleshooting - cooling system – Carrier 48EL User Manual

Page 10

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Lubrication

FAN MOTOR BEARINGS are factory lubricated

and do not require service for 3 to 5 years,

depending upon type of service. When required,

clean and relubricate per motor manufacturer’s
instructions.

COMPRESSOR contains a factory oil charge. If oil

is lost thru leakage, refer to Carrier Standard

Service Techniques Manual SM-1, Chapter 1 for oil

recharging procedure.

TROUBLESHOOTING - HEATING SYSTEM

Burner Does Not Operate

Power failure — Power switch off; blown line

fuse; defective wiring. .

No power to controls — thermostat set too low,

dirty or defective; defective transformer, faulty
limit switch.

Burner does not ignite — no gas to unit; faulty

valve or pilot switch; faulty spark ignitor; dirty

pilot.

Burner Operates, But Heating is Inadequate

Unit undersized — unit size selected incorrectly

Fuel input too low ~ wrong orifice size,

regulator set too low

Thermostat opens too soon ~ wrong antici­

pator setting, thermostat out of calibration,

wrong

thermostat

location;

thermostat

set

wrong.

Limit switch cycles burner

faulty fan switch or motor;

wrong; duct system restricted

Poor Combustion and Flame Characteristics

Smoky flame — insufficient air, flue restriction.

Noisy burner — too much air, incorrect input

TROUBLESHOOTING - COOLING SYSTEM

Compressor Does Not Start

Power failure — power switch off; blown line

fuse, defective wiring.

No power to controls ~ thermostat set too low;

or dirty or defective, defective transformer.

— dirty filters;

limit switch set

contactor coil open; loose leads from closed

contactor.

Power to compressor — motor windings open,
contactor closes, then opens

Compressor Runs But Cooling is Insufficient

Low suction pressure — restricted airflow;

capillary

tubes

restricted;

low

refrigerant

charge.

Low head and high suction pressure — defective

compressor valves.

Indoor fan stopped — loose or broken leads,

faulty capacitor; internal short circuit

Compressor Does Not Restart

Power failure — power switch off, blown line

fuse

Power at closed contactor — faulty start relay

or capacitor, contactor, run capacitor or com­
pressor, low line voltage (must be within 10%

of nameplate voltage )

Compressor Cycles on Overload

Insufficient condenser air — check condenser

fan position in reference to orifice as in Fig 11.

Condenser air restricted ^ dirty coil, airflow

restricted

Condenser air recirculating — obstruction de­

flecting airflow.

Improper line voltage — circuit overloaded;

loose electrical connections

Faulty run capacitor — capacitor shorted or low

on capacitance (mfd)

Noncondensables in system — moisture or air in

system

System overcharged — high head pressure

causes by excessive refrigerant.

No refrigerant in system — leak in system.

System restricted — capillary tubes restricted or

plugged, kinked tubing, dirty strainer

Fan slipping on motor shaft — setscrews either

loose or missing from fan.

Fan motor bearing seized — lack of oil or

bearing failure.

Fan motor defective — internal short circuit