Indoor Airflow; Metering Devices; Liquid Line Strainers - Carrier 50HS018 Installation, Start-Up And Service Instructions Manual

Indoor Airflow —
The indoor airflow does not require
checking unless improper performance is suspected. If a prob-
lem exists, be sure that all supply- and return-air grilles are
open and free from obstructions, and that the air filter is clean.
When necessary, refer to Indoor Airflow and Airflow Ad-
justments section on page 22 to check the system airflow.
Metering Devices —
fixed orifices and are located in the inlet header to the indoor
and outdoor coils.
SYMPTOM
Compressor and out-
door fan will not start.
Compressor will not
start but outdoor fan
runs.
Three-phase scroll
compressor
(size 048 and 060
units only) makes ex-
cessive noise, and
there may be a low
pressure differential
Compressor cycles
(other than normally
satisfying thermostat).
Compressor operates
continuously.
Refrigerant metering devices are
Table 11 — Cooling and Heating Troubleshooting Chart
CAUSE
Power failure
Fuse blown or circuit breaker tripped
Defective thermostat, contactor, transformer,
control relay, or defrost board
Insufficient line voltage
Incorrect or faulty wiring
Thermostat setting too high
Units have a 5-minute time delay
Faulty wiring or loose connections in
compressor circuit
Compressor motor burned out, seized, or
internal overload open
Defective run capacitor, overload,
or PTC (positive temperature coefficient)
thermistor
One leg of 3-phase power dead
Low input voltage (20% low)
Scroll compressor is rotating in the
wrong direction
Refrigerant overcharge or undercharge
Defective compressor
Insufficient line voltage
Blocked outdoor coil
Defective run/start capacitor, overload,
or start relay
Defective thermostat
Faulty outdoor-fan motor or capacitor
Damaged reversing valve
Restriction in refrigerant system
Dirty air filter
Unit undersized for load
Thermostat set too low
Low refrigerant charge
Leaking valves in compressor
Frosted coil with incorrect defrost operation
Air in system
Outdoor coil dirty or restricted
Liquid Line Strainers —
protect metering device) are made of wire mesh and are lo-
cated in the liquid lines on the inlet side of the metering
devices.
Check valves are also located in the liquid lines near
the strainers. The strainers are the larger of the two
components.
Call power company.
Replace fuse or reset circuit breaker.
Replace component.
Determine cause and correct.
Check wiring diagram and rewire correctly.
Lower thermostat setting below room temperature.
DO NOT bypass this compressor time delay — wait
for 5 minutes until time-delay relay is deenergized.
Check wiring and repair or replace.
Determine cause. Replace compressor.
Determine cause and replace.
Replace fuse or reset circuit breaker.
Determine cause.
Determine cause and correct.
Correct the direction of rotation by reversing the
3-phase power leads to the unit.
Recover refrigerant, evacuate system, and recharge
to capacities shown on nameplate.
Replace and determine cause.
Determine cause and correct.
Determine cause and correct.
Determine cause and replace.
Replace thermostat.
Replace.
Determine cause and correct.
Locate restriction and remove.
Replace filter.
Decrease load or increase unit size.
Reset thermostat.
Locate leak, repair and recharge.
Replace compressor.
Check defrost time settings. Reset as necessary.
Check defrost temperature switch. Replace as necessary.
Recover refrigerant, evacuate system, and recharge.
Clean coil or remove restriction.
30
The liquid line strainers (to
REMEDY