Manitowoc Ice STH003 manual Procedure, Step

PROCEDURE

Step						.
1. Determine the ice	Air temp. entering condenser:
machine operating			°				°
conditions.					90 F/32.2 C
	Air temp. around ice machine:
					80°F/26.7°C
	Water temp. entering water fill valve:
					70°F/21.1°C
2A. Refer to “Cycle Time”
and “Operating Pressure”	19.1 - 21.7 minutes
charts for ice machine
	Published freeze cycle time:
model being checked.
Using operating conditions	20-3 PSIG
from Step 1, determine
	Published freeze cycle
published freeze cycle time
	suction pressure:
and published freeze cycle
suction pressure.
			Published Freeze Cycle Time
					(minutes)
2B. Compare the published	1		5			10	15	20
freeze cycle time and
published freeze cycle
suction pressure. Develop a
chart.	20		16			12	8	3
		Published Freeze Cycle Suction
				Pressure (psig)
	In the example, the proper suction
	Pressure should be approximately 16
	PSIG at 5 minutes; 12 PSIG at 10
	Minutes; etc.
3. Perform an actual suction	Manifold gauges were connected to the
pressure check at the	example ice machine and suction pressure
beginning, middle and end	readings taken as follows:								PSIG
of the freeze cycle. Note the	Beginning of Freeze cycle:
times at which the readings			30 (at			1 min.)
are taken.
	Middle of freeze cycle:
			22 (at			10 min.)
	End of freeze cycle:
			8 (at 20 min.)
4. Compare the actual	In this example, the suction pressure is
freeze cycle suction	considered high throughout the freeze
pressure (Step 3) to the	cycle. It should have been:
published freeze cycle time	Approximately 20 PSIG
and pressure comparison	(at 1 minute) – not 30
(Step 2B). Determine if the	Approximately 12 PSIG
suction pressure is high,
	(at 10 minutes) – not 22
low or acceptable.
	Approximately – 3 PSIG
	(at 20 minutes) – not 8

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