Foster FMIC180 manual Service Specification, Component Description, Service Diagnosis

At this point, the unit initiates the defrost cycle. The hot gas circulating into the evaporator serpentine causes a slight melting of the ice cubes which get released from their moulds. Once entirely released the ice cubes drop simultaneously into the ice storage bin below; in doing so they move apart from the evaporator bottom end of the plastic deflector. This plastic deflector has on its upper left corner a metal actuator which, on account of the deflector’s swinging motion, caused by the ice dropping in the bin, pushes the microswitch plunger to open and close the N.C. contacts. This will, in turn, de-activate the relay contacts that control the hot gas and water drain valve which get de-energised allowing the unit to start a new freezing cycle. On later models the sequence is controlled by a magnetic switch attached to the bottom right hand side of the deflector.

When the ice bin is full of ice, the last batch of ice cubes released from the evaporator accumulates to keep the bottom end of the plastic deflector in open position; with the N.C. microswitch/magnetic switch contact open for longer than 30sec the entire unit stops.

7.Service Specification

In servicing a machine, it is offen useful to compare individual units operating characteristics to those of a normally operating machine. The data that follows gives those characteristics; however, be aware that these values are for a NEW, CLEAN machine. USE THESE NUMBERS AS A GUIDELINE ONLY.

COMPONENT	R22 - R404A Machines
Reservoir level	30-35 mm
Cube Size Control Ice Sensor
distance from evaporator	7mm
High Pressure Safety Switch
Water-cooled	C/IN 13 bar - C/OUT 20 bar
Fan Pressure Control
Air-cooled only	C/IN 15 bar - C/OUT 13 bar

7.1Operating Characteristics

On air-cooled models during the freezing cycle the discharge pressure is maintained between 13 and 15 bar by means of fan pressure control and at the same time, the suction pressure will also decline reaching its lowestpoint just before harvest. Compressor amps experience a similar drop.

On water-cooled models the discharge pressure is constantly maintained during the freeze cycle by the water regulating valve at 13 bar. However, suction pressure and compressor amps, will still decline as the machine freezes ice.

7.2	Freeze Cycle
		R22 Machines	R404A Machines
	Suction Pressure at the beginning of the Freeze Cycle	2.8/2.5 bar	3.5 bar
	Average Discharge Pressure A/C	14 bar	15.5 bar
	Average Discharge Pressure W/C	13 bar	17 bar
	Suction Pressure at the end of the Freeze Cycle	1.5/1.3 bar	1.7 bar
	Freeze Time	20/25 Minutes	20/25 Minutes
	Amps. drawn at the beginning of the Freeze Cycle FMIC 180	5.5	5.0
	Freeze Cycle FMIC 260 Beginning	7.6	8.0
	Amps. drawn at the end of the Freeze Cycle FMIC 180	4.4	4.0
	Freeze Cycle FMIC 260 End	4.6	5.5
	Suction Pressure at the end of the Freeze Cycle	1.5	1.7

7.3	Harvest Cycle
		R22 Machines	R404A Machines
	Average Discharge Pressure	9 bar	13/15 bar
	Average Suction Pressure	7.5 bar	7.5 bar

The values listed are representative of values seen at a wide range of air and water temperatures and are for a normal cube size. When comparing these figures to field data, allow a variation from each end of the range given.

Refrigerant charge	R22	Machines	R404A Machines
Model	FMIC180	FMIC260	FMIC180	FMIC260
Air cooled	l000gr	l500gr	1200gr	1700gr
Water cooled	650gr	700gr	1200gr	900gr
Refrigerant metering device
Expansion valve

NOTE: Always check nameplate on individual ice machine for special refrigerant charge before charging the refrigeration system. Such refrigerant charge is the average charge for the Modular Cubers. However, it is important to check nameplate for each machine.

8.Component Description

8.1Toggle Switch - ICE/OFF/WASH

Is a double pole-double throw switch. In OFF position keeps the electric circuit open through the P.C. Board built-in ON-OFF switch. In ICE position the unit electric circuit is closed for normal operation of electric component.

In WASH position opens the electric circuit to the compressor contactor and fan motors and closes the circuit for the water pump.

8.2Electronic Control Board

Located in the control box, this board is the brain of the system as it governs the ice machine cyclematic through sensors, relays and switches. The sensor is the ice thickness control which signals to the P.C. Board to energise the built-in relay that controls the Hot Gas Valve and Water Drain Valve. The other contactor to which the P.C. Board supply power is on the compressor line.

The switches are: the Toggle ICE/OFF/WASH switch and the N.C. microswitch/magnetic switch actuated by the evaporator deflector that signals to the P.C. Board that ice has been defrosted and released, so that the relay controlling the defrost can be disconnected.

The P.C. Board is equipped with an electronic safety timer that turns-on automatically the unit to defrost cycle when the freezing cycle is longer than 40 minutes and trips-off the complete unit when defrost cycle is longer then 4 minutes.

9.Service Diagnosis.

The table below is intended as a quick reference to aid the service engineer to determine the cause of a particular malfunction as well as the recommended repair. It is not intended to be an exclusive list.

Reference to other portions of the manual inclusive of wiring diagrams, installation and operating instructions are recommended to better determine the cause of a problem.

Symptom	Possible cause	Correction
Warning RED LED ON	See Page 20.	See Page 20.
No Warning RED LED ON	P.C. Board inoperative	Remove board and check.
	No power to machine	Check electrical source.
Bin Full Amber LED ON	Bin Full of Ice.	None.
	Magnetic Switch inoperative	Check and replace.
Machine Runs but compressor not running.	P.C. Board compressor relay open.	Test and Replace.
	Compressor Contactor open.	Test and Replace.
	Compressor relay open.	Test and Replace.
	Compressor Winding open.	Test and Replace.
Machine runs, makes ice,	Ice thickness control open.	Check sensor fingers to determine if covered
does not try to harvest.		with scale or sediment.
	Water Too soft	Water electrical conductivity must be higher
		than 20 uS.
		Machine will not run with demineralized water.
	Built in relay on P.C. Board open.	Check and replace P.C. Board.
Machine runs makes ice and	Low Refrigerant Charge.	Check system for correct refrigerant charge.
harvests ice but very slowly.		Check system for leak.
Low ice capacity	High discharge pressure due to under	Reclaim refrigerant and recharge with the
	condensing or refrigerant overcharge.	correct amount.
	Inefficient Compressor.	Replace compressor.
	Dirty condenser.	Clean Condenser.
	Low water flow (water cooled only).	Check and repair.
	High air temperature (Air-cooled only).	Check temperature of air entering condenser.
Machine makes irregular ice.	Water distributor blocked.	Clean water distributor.
	Expansion valve superheat wrong.	Adjust or replace.
	Low refrigerant charge.	Check for leak, reclaim refrigerant and
		recharge with correct amount.

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