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Medium and large cabinet freezers – Heatcraft Refrigeration Products Refrigeration System H-IM-82B User Manual

Page 8

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8

Service Information

All

units are designed for maximum durability, reliability and

simplicity.

comes to you ready for operation, fully charged and

with all controls preset at the factory. The following information is

provided as an aid in the event that service is required.

Maintenance

The evaporator section of a

system should be checked at

least once for proper defrosting because the amount and pattern

of frosting can vary greatly. The frost build-up is dependent on

the temperature of the room, the type of product being stored,

how often new product is brought into the room and percentage

of time the door to the room is open. It may be necessary to

periodically change the number of defrost cycles or adjust the

duration of defrost.

System Standard Maintenance Guidelines

After first year of operation and under normal usage, maintenance

should cover the following items at least once every six months:

1. Check and tighten

ALL electrical connections.

2. Check all wiring and insulators.
3. Check contactors for proper operation and for worn

contact points.
4. Check all fan motors. Tighten motor mount bolts/ nuts

and tighten fan set screws.

5. Clean the condenser coil surface.
6. Check the operation of the control system. Make certain

all safety controls are operating properly.

7. Check that all defrost controls are functioning properly.
8. Clean the evaporator coil surface.
9. Clean the drain pan and check the drain pan and drain line

for proper drainage.

Refrigeration Sequence of Operation

1. Power is provided to the temperature control, compressor

contactor and cooler evaporator fans.

2. The temperature controller closes and energizes the

compressor contactor, starting the compressor,

evaporator and condenser fan(s).

3. When the system reaches the desired box temperature,

the temperature control will de-energize the compressor

contactor. Evaporator fans will continue to operate at

this point.

4. When the fixture temperature rises above the set point

and minimum off-time has elapsed, the temperature

control will close and re-energize the compressor contactor.

Electric Defrost Sequence of Operation
for Freezers

1. During normal operation, at the preset time intervals,

the temperature/defrost control will de-energize the

compressor contactor and evaporator fans and energize

the defrost heaters. These functions are controlled

through relays on the controller.

2. When the coil has defrosted fully and has reached the

preset coil temperature (as sensed by the coil

temperature sensor) the defrost heater de-energizes

and the fan delay and drip sequences begin.

3. The temperature/defrost control energizes the

compressor contactor, starting the compressor and

condenser fan(s).

4. Freezer evaporator fans will be energized by the

temperature/defrost control when the coil temperature

reaches 35°F or fan delay time has elapsed.

Freezer Defrost Control -
Medium & Large Cabinet

freezer units come factory equipped with an electronic

temperature/defrost control. There are 2 different models of

electronic control used and it is important to determine which

one is present on your unit before altering any factory settings.

Please refer to the picture of the controller display on this page

to determine the model used. Instructions for any necessary

reprogramming are included in this manual on pages 8-10.

Medium and Large Cabinet Freezers

Dixell Electronic Controller

The Dixell XR-60CX and the Dixell XR-60C are fully

configurable electronic refrigeration controllers. All

parameter values are reprogrammable and are stored in the

non-volatile memory.
The controllers use two levels of programming that can be

accessed through the keypad. The first level is the user level.

It gives access to six settings; temp. differential, defrost cycle

intervals, defrost termination temperature, draining time,

defrost fan delay, and fan stop temperature.
The second level is the service level. It allows access to all

other parameters. It is recommended that changes in this

level be made only by a qualified technician.

Front Panel Commands

XR-60CX Controller XR-60C Controller

USE OF LEDS
Each LED function is described in the following table.

LED

LED MODE

FUNCTION

ON

Compressor enabled

Flashing

-Programming Phase (flashing with )

- Anti-short cycle delay enabled

ON

Defrost enabled

Flashing - Programming Phase (flashing with )

- Drip time in progress

ON

Fans enabled

Flashing

Fans delay after defrost in progress

(60CX only)

ON

A temperature alarm occurred

2.

Fr

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