Manitowoc Ice QF2200 Section, Refrigeration System, Procedure, Discharge Pressure High Checklist

Section 7 Refrigeration System

ANALYZING DISCHARGE PRESSURE DURING FREEZE OR HARVEST CYCLE

Procedure

1. Determine the ice machine operating conditions:

Air temp. entering condenser	______
Air temp. around ice machine	______
Water temp. entering water reservoir	______

2.Refer to Cycle Times/24 Hour Ice Production/ Refrigeration Pressure Chart for ice machine being checked.

Use the operating conditions determined in step 1 to find the published normal discharge pressures. Compare to actual discharge pressure readings.

3.Measure the actual discharge pressure.

4.Compare the actual discharge pressure (step 3) with the published discharge pressure (step 2).

The discharge pressure is normal when the actual pressure falls within the published pressure range for the ice machine’s operating conditions.

Discharge Pressure High Checklist

Possible Cause	Check/Correct
Improper installation	See “Installation/Visual Inspection Checklist”
Restricted condenser air flow	High inlet air temperature
	Condenser discharge air recirculation
	Dirty condenser fins
	Defective fan motor
	Defective fan cycle control (QC700/QF800 only)
Improper refrigerant charge	Overcharged
	Non-condensables in system
	Wrong type of refrigerant
Other	Non-Manitowoc components in system
	High side refrigerant lines/component restricted (before mid-condenser)
	Defective head pressure control valve (RFC2085/RFC2385 only)

Discharge Pressure Low Checklist

Possible Cause	Check/Correct
Improper installation	See “Installation/Visual Inspection Checklist”
Improper refrigerant charge	Undercharged
	Wrong type of refrigerant
Other	Non-Manitowoc components in system
	Defective head pressure control valve (RFC2085/RFC2385 only)
	Defective fan cycle control (QC700/QF800 only)
	Suction pressure is too low and affecting discharge pressure. Refer to
	suction pressure low checklist.
	No water or insufficient pressure
	Starving expansion valve
	Defective compressor
	Moisture in refrigeration system

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

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