Carrier Miracool owner manual Refrigeration System, Malfunction, Possible Cause, Solution

TABLE 3 – REFRIGERATION SYSTEM SERVICE AND ANALYSIS CHART

REFRIGERATION SYSTEM

MALFUNCTION		POSSIBLE CAUSE		SOLUTION
	1.	Line cord not plugged in.	1.	Plug in the cord.
Compressor will not start	2. Fuse removed or blown.		2.	Replace fuse.
	3.	Overload protector tripped.	3.	Refer to electrical section.
- no hum -	4. Temp control stuck in open position.		4.	Repair or replace temp control.
	5.	Wiring improper or loose.	5.	Check wiring against diagram.
Compressor will not start	1.	Low voltage to unit.	1.	Determine reason and correct.
			2.	Determine reason and correct, replace if
	2.	Relay failing to close
				necessary.
- hums but trips on overload
	3.	Starting capacitor defective.	3.	Determine reason and replace.
protector.
	4.	Improperly wired.	4.	Check wiring against diagram.
	1.	Low voltage to unit.	1.	Determine reason and correct.
	2.	Relay failing to open.	2.	Determine reason and correct, replace if
Compressor starts but does not				necessary.
switch off of start winding.	3. Run capacitor defective.		3.	Determine reason and replace.
	4.	Compressor mounting winding is open or	4.	Determine cause, correct, and replace
		shorted.		compressor.
	1.	Additional current passing through overload	1.	Check wiring diagram. Check for added fan
				motors, pumps, etc. connected to wrong side of
		protector.
				protector.
Compressor starts and	2.	Low voltage to unit.	2.	Determine reason and correct.
	3.	Overload protector defective.	3.	Check current, replace protector.
runs, but short cycles on
	4.	Run capacitor defective.	4.	Determine reason and replace.
overload protector.
			5.	Check ventilation, restrictions in cooling medium,
	5.	Excessive discharge pressure.
				restrictions in refrigeration system.
	6.	Compressor too hot - return gas hot.	6.	Check refrigerant charge (fix leak if necessary).
				Check airflow across condenser.
	1.	Overload protector.	1.	Check wiring diagram for correct wiring.
Unit runs OK, but short	2.	Cold control.	2.	Differential set too close.
	3.	Overcharge.	3.	Reduce refrigerant charge.
cycles.
	4.	Air in system.	4.	Recover and recharge.
	5.	Undercharge.	5.	Fix leak and recharge with refrigerant.
	1.	Dirty condenser.	1.	Clean condenser.
Unit operates long or	2.	Shortage of refrigerant.	2.	Fix leak, add charge, correct charge.
	3.	Temperature control contacts stuck or frozen.	3.	Replace temperature control.
continuously.
	4.	Evaporator coil iced.	4.	Defrost.
	5.	Restriction in refrigeration system.	5.	Determine location and remove.
Start capacitor open, shorted or	1.	Relay contacts not opening properly.	1.	Replace relay.
	2.	Low voltage to unit.	2.	Determine reason and correct.
blown.
	3.	Improper relay.	3.	Replace.
Run capacitor open, shorted	1.	Improper capacitor.	1. Determine correct size and replace.
	2.	Excessively high line voltage (110% of rated
or blown			2. Determine reason and correct.
		max).
	1.	Incorrect relay.	1. Check and replace.
Relay defective or burned out	2.	Line voltage too high or too low.	2. Determine reason and replace.
	3.	Relay being influenced by loose vibrating
			3. Remount rigidly.
		mounting.
	1.	Control setting too high.	1. Reset control.
Space temperature too high	2. Overcharged with refrigerant.		2. Recover refrigerant and recharge with proper
				charge specified on data plate.
	3.	Inadequate air circulation.	3. Improve air movement.
Cooler freezing beverage	1. Temperature control		1.	Reset control.
	1.	Loose parts or mountings.	1.	Find and tighten.
Unit noisy	2.	Tubing rattles.	2.	Reform to be free of contact.
	3.	Bent fan blade causing vibration.	3.	Replace blade.
	4.	Fan motor bearings worn.	4.	Replace motor.

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