Carrier 38AH044-084 specifications Troubleshooting

TROUBLESHOOTING (cont)

	PROBLEM		SOLUTION
COMPRESSOR STOPS ON OIL PRESSURE SWITCH
1.	Oil level too low or too high.	1.	Check oil level requirements; adjust oil level until sight
2. Compressor is short cycling.			glass is ®lled1¤8 to 1¤3 when running.
		2.	Check for
			a) Thermostat location and operation.
			b) Safety device lockout circuit operation.
			c) End-of-cycle control and timer operation.
3.	Crankcase heater off.		d) Low-pressure switch and relay operation.
		3.	Check relay operation; replace crankcase heater(s), if
4.	Low refrigerant charge.		defective.
		4.	Adjust charge as required.
5. Refrigerant ¯oodback.		5.	Adjust TXV superheat.
6.	Evaporator coil is blocked or iced.	6.	Check and correct as required.
7.	Evaporator fan not operating.	7.	Check and correct as required.
8.	Distributor and/or TXV too large.	8.	Check sizing at design conditions; change if incorrect
9.	Suction riser too large.		for current application.
		9.	Check line sizing at minimum design condition; change
10.	Defective oil pressure switch.		piping if incorrect.
		10.	Check switch for proper operation; check capillary lines
11. Plugged oil pump inlet screen.			for plugged lines.
		11.	Clean oil pump screen.
12. Faulty oil pump drive segment.		12.	Replace drive segment.
13. Worn oil pump.		13.	Replace bearing head assembly.
14. Worn compressor bearings.		14.	Replace compressor; see 06E service instructions.
COMPRESSOR RUNNING BUT COOLING INSUFFICIENT
Suction Pressure Low
1.	Refrigerant charge low.	1.	Add refrigerant.
2.	Head pressure low.	2.	Check refrigerant charge.
3.	Air ®lters dirty.		Check outdoor-air fan thermostat settings.
		3.	Clean or replace ®lters.
4.	Expansion valve power head defective.	4.	Replace power head.
5.	Indoor coil partially iced.	5.	Check low-pressure setting.
6.	Indoor air¯ow restricted.	6.	Remove obstruction.
Suction Pressure High
1.	Unloaders not functioning.	1.	Check unloader adjustments.
2.	Compressor valve defective.		Check unloader setting.
		2.	See 06E compressor service literature.
3.	Heat load excessive.	3.	Check for open doors or windows in vicinity of fan coil.
UNIT OPERATES TOO LONG OR CONTINUOUSLY
1.	Low refrigerant charge.	1.	Add refrigerant.
2.	Control contacts fused.	2.	Replace control.
3.	Air in system.	3.	Purge and evacuate system.
4.	Partially plugged expansion valve or ®lter drier.	4.	Clean or replace.
SYSTEM IS NOISY
1.	Piping vibration.	1.	Support piping as required.
2.	Compressor noisy.	2.	Check valve plates for valve noise. Replace compressor
			if bearings are worn.
COMPRESSOR LOSES OIL
1.	Leak in system.	1.	Repair leak.
2.	Crankcase heaters not energized during shutdown.	2.	Check wiring and relays. Check heater and replace if
3.	Improper interconnecting piping design.		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.	1.	Repair leak and recharge.
2.	Expansion valve opens too wide.	2.	Adjust expansion valve.
FROSTED LIQUID LINE
1.	Restricted ®lter drier.	1.	Remove restriction or replace.
COMPRESSOR WILL NOT UNLOAD
1.	Defective unloader.	1.	Replace unloader.
2.	Defective capacity control solenoid valve (if used).	2.	Replace valve.
3.	Miswired capacity control liquid line solenoid (if used).	3.	Rewire correctly.
4.	Weak, broken, or wrong valve body spring.	4.	Replace spring.
COMPRESSOR WILL NOT LOAD
1.	Miswired capacity control liquid line solenoid (if used).	1.	Rewire correctly.
2.	Defective capacity control solenoid valve (if used).	2.	Replace valve.
3.	Plugged strainer (high side).	3.	Clean or replace strainer.
4.	Stuck or damaged unloader piston or piston ring(s).	4.	Clean or replace the necessary parts.

Copyright 1998 Carrier Corporation

Manufacturer reserves the right to discontinue, or change at any time, speci®cations or designs without notice and without incurring obligations.

Book	1	PC 111	Catalog No. 563-704	Printed in U.S.A.	Form 38AH-15SI	54	10-98	Replaces: 38AH-14SI
Tab	3a