Manitowoc Ice QF2300, QF0800, QC0700 Refrigeration System, Section, Analyzing Suction Pressure

Refrigeration System Section 7

ANALYZING SUCTION PRESSURE

NOTE: Analyze discharge pressure before analyzing suction pressure. High or low discharge pressure may be causing high or low suction pressure.

Suction Pressure High Checklist

Possible Cause	Check/Correct
Improper installation	See “Installation/Visual Inspection Checklist”
Discharge pressure	Discharge pressure is too high, and is affecting suction pressure
	(See “Freeze Cycle Discharge Pressure High Checklist”
Improper refrigerant charge	Overcharged
	Wrong type of refrigerant
	Non condensables in system
Other	Non-Manitowoc components in system
	TXV flooding (check bulb mounting)
	Defective compressor
Suction Pressure Low Checklist

Possible Cause	Check/Correct
Improper installation	See “Installation/Visual Inspection Checklist”
Discharge pressure	Discharge pressure is too low, and is affecting suction pressure (See “Freeze Cycle
	Discharge Pressure Low Checklist”)
Improper refrigerant charge	Undercharged
	Wrong type of refrigerant
Other	Non-Manitowoc components in system
	Restricted/plugged liquid line drier
	Restricted/plugged tubing in suction side of refrigeration system
	Expansion valve starving
	No water or insufficient pressure
	Defective compressor
	Moisture in refrigeration system
	Dirty Evaporator
	Defective Fan Cycle Control
	RFC2085/RFC2385 Only - Defective Head Pressure Control

NOTE: Do not limit your diagnosis to only the items listed in the checklists.

7-8 Revised 8/2003 Part No. 80-1214-3