Carrier 48DH - Manual (Page 13)

OUTDOOR FAN ADJUSTMENT - The required
fan position is shown in Fig. 9. Loosen setscrews,
set fan at dimension indicated and retighten
Fig. 9 — Outdoor Fan Clearance
Adjusting Spark Ignition — If pilot fails to ignite
on size 003 — 005 natural gas units, check the
spark ignition system as follows:
1. Shut off power to ignitor.
2. Check that spark gap is 1/8 — 3/16 inch.
3. Make sure that spark generator is securely
grounded.
4. Check that high-voltage lead is securely con­
nected between generator and electrode body.
5. Restore power. Check for 24-volt supply to
primary side of generator.
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 thai leakage, refer to Carrier Standard
Seiwice Techniques Manual SM-1, Chapter 1 for oil
recharging procedure.
TROUBLESHOOTING - HEATING SYSTEM
Burner Will 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; blown fusestat
Burner will not ignite — no gas to unit; faulty
valve or pilot switch, faulty glow coil or 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 antic­
ipator setting: thermostat out of calibration,
wrong thermostat location; thermostat set
wrong
Limit switch cycles burner — dirty filters,
faulty fan switch or motor, limit switch set
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 Will Not Start
Unequalized system pressure — Give temporary
capacitance boost. Refer to Check Compressor
Start in Start-Up section.
Power failure — power switch o f f ; blown line
fuse; defective wiring.
No power to controls — thermostat set too low,
or dirty or defective, defective transformer,
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 air flow,
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 Will Not Restart
Power failure — power switch o f f , blown line
fuse.
Power at closed contactor — faulty start relay
or capacitor (if used) (add accessory start
package), 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. 9.
Condenser air restricted — dirty coil, air flow
restricted.
Condenser air recirculating — obstruction de­
flecting air flow
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 — excessive refrigerant
No refrigerant in system — leak in system
System restricted — capillary tubes restricted or
plugged; kinked tubing.
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.
For replacement items use Carrier Specified Parts.
Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.
Tab 6 Form 48DH-6SI Supersedes 48DH-3SI Printed in U S A 9-75 Codes D and MS Cataiog No 534—801