Emerson 3000/ITR manual Troubleshooting

		Troubleshooting
Table 14 Compressor and refrigeration system troubleshooting
Symptom	Possible Cause	Check or Remedy
	Power Off	Check main switch, fuses or CBs and
		wiring
		Re-set units with overload option
Compressor will not start	Current overload open	manually. Allow compressor to cool for
		internal overloads to reset.
	Loose electrical connections	Tighten connections
	Compressor motor burned out	Check and replace compressor if
		defective.
	No call for cooling	Check monitor status.
		Hold screwdriver over solenoid and check
Compressor will not operate,	Solenoid valve not energizing	for magnetic field. This indicates solenoid
contactor not pulling in		is energized.
	Low pressure switch not making contact	Check gas pressure - manually energize
		low pressure switch.
Compressor will not operate,	High pressure switch open	Reset switch. Refer to other refrigeration
contact not pulling in		troubleshooting suggestions.
Compressor contactor pulled in but	Blown fuse or tripped CB	Check for line voltage after fuses or CBs,
compressor will not operate		and after contactors.
		Check for low gas pressure. Compressor
Compressor runs for three minutes	Low pressure switch not closing	is running on Positive Start Kit (air cooled
then stops; contactor drops out.		systems only)
	Liquid line solenoid valve not opening	Check magnetic field to see if energized.
	Dirty condenser or drycooler fins	Clean coil.
	Condenser equipment not operating	Check operation.
High discharge pressure	High refrigerant charge	Check refrigerant charge.
	Hot gas bypass valve adjusted	Adjust properly.
	improperly
	Water regulating valve adjusted	Adjust properly.
	improperly
	Excessive fluid flow through condenser	Adjust fluid regulating valve
	Suction service valve partially closed	Open the valve.
Low discharge pressure	Faulty head pressure control valve or	Replace if defective.
	condenser fan speed control
	Compressor rotation in reverse direction	Check for proper power phase wiring to
		unit and to compressor motor.
		Check for leaks, repair, and add
	Insufficient refrigerant in system	refrigerant for air cooled. Evacuate and
		recharge for water/glycol unit.
	Dirty air filters	Change filters.
	Plugged filter-drier	Replace filter.
	Improper superheat adjustment	Reset expansion valve for 10-15°F
		(6-8°C)
Low suction pressure
	Defective expansion valve sensing	Replace element
	element
		Check duct work for closed dampers.
	Poor air distribution	Check for under-floor restrictions at or
		near the unit.
	Low condensing pressure	Check head pressure control device.
	Slipping belts	Inspect and adjust

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