Carrier 38AH044-134 - Manual (Page 52)

TROUBLESHOOTING (coni)
PROBLEM SOLUTION
COMPRESSOR STOPS ON OIL PRESSURE SWITCH
1. Oil level too low or too high.
2. Compressor is short cyciing.
3. Crankcase heater off.
4. Low refrigerant charge.
5. Refrigerant fioodback.
6. Evaporator coii is biocked or iced.
7. Evaporator fan not operating.
8. Distributor and/or TXV too iarge.
9. Suction riser too iarge.
10. Defective oii pressure switch.
11. Plugged oil pump inlet screen.
12. Faulty oil pump drive segment.
13. Worn oii pump.
14. Worn compressor bearings.________
Check oil level requirements, adjust oil level until sight
glass is filled
Vs to Vs when running
Check for
a) Thermostat location and operation
b) Safety device lockout circuit operation.
c) End-of-cycle control and timer operation
d) Low-pressure switch and relay operation.
Check relay operation; replace crankcase heater(s), if
defective
4. Adjust charge as required
5 Adjust TXV superheat.
6 Check and correct as required
7. Check and correct as required.
8 Check sizing at design conditions; change if incorrect
for current application
9 Check line sizing at minimum design condition, change
piping if incorrect
Check switch for proper operation; check capillary lines
for plugged lines
Clean oil pump screen.
Replace drive segment
Replace bearing head assembly.
Replace compressor; see 06E service instructions
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3.
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COMPRESSOR RUNNING BUT COOLING INSUFFICIENT
Suction Pressure Low
1. Refrigerant charge low.
2. Head pressure low.
3. Air filters dirty.
4. Expansion valve power head defective.
5. Indoor coil partially iced.
6. Indoor airflow restricted.
Suction Pressure High
1. Unloaders not functioning.
2. Compressor valve defective.
3. Heat load excessive.
1 Add refrigerant
2. Check refrigerant charge.
Check outdoor-air fan thermostat settings.
3. Clean or replace filters.
4. Replace power head
5 Check low-pressure setting.
6.
Remove obstruction
1. Check unloader adjustments
Check unloader setting.
2. See 06E compressor service literature.
3. Check for open doors or windows in vicinity of fan coil
UNIT OPERATES TOO LONG OR CONTINUOUSLY
1. Low refrigerant charge.
2. Control contacts fused.
3. Air in system.
4. Partially plugged expansion valve or filter drier. 1. Add refrigerant.
2 Replace control
3 Purge and evacuate system
4. Clean or replace______________
SYSTEM IS NOISY
1. Piping vibration.
2. Compressor noisy. 1 Support piping as required
2. Check valve plates for valve noise Replace compressor
if bearings are worn.____________________________________
COMPRESSOR LOSES OIL
1. Leak in system.
2. Crankcase heaters not energized during shutdown.
3. Improper interconnecting piping design.____________
1. Repair leak.
2. Check wiring and relays Check heater and replace if
defective
3. Check piping for oil return Replace if necessary
FROSTED SUCTION LINE
1. Expansion valve admitting excess refrigerant. 1. Adjust expansion valve
HOT LIQUID LINE
1. Shortage of refrigerant due to leak.
2. Expansion valve opens too wide.
1 Repair leak and recharge.
2, Adjust expansion valve
FROSTED LIQUID LINE
1. Restricted filter drier. 1 Remove restriction or replace.
COMPRESSOR WILL NOT UNLOAD
1. Defective unloader.
2. Defective capacity control solenoid valve (if used).
3. Miswired capacity control liquid line solenoid (if used).
4. Weak, broken, or wrong valve body spring.______________
1 Replace unloader
2 Replace valve,
3 Rewire correctiy.
4 Replace spring
COMPRESSOR WILL NOT LOAD
1. Miswired capacity control liquid line solenoid (if used).
2. Defective capacity control solenoid valve (if used).
3. Plugged strainer (high side).
4. Stuck or damaged unloader piston or piston ring(s).
1 Rewire correctly
2 Replace valve
3 Clean or replace strainer
4 Clean or replace the necessary parts.
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