Nor-Lake LABORATORY REFRIGERATORS AND FREEZERS User Manual

LABORATORY

REFRIGERATORS AND FREEZERS

Installation, Operation and

Maintenance Instructions

INSPECTION

When the equipment is received, all items should be carefully checked against the bill of lading to
insure all crates and cartons have been received. All units should be inspected for concealed
damage by uncrating the units immediately. If any damage is found, it should be reported to the
carrier at once, and a claim should be filed with the carrier. This equipment has been inspected and
tested in the manufacturing facility and has been crated in accordance with transportation rules and
guidelines. Manufacturer is not responsible for freight loss or damage.

INSTALLATION

GENERAL

After the unit crate and crate base have been removed, locate the casters or legs if applicable
found inside the cabinet (casters may be pre-installed). Attach the casters or legs to the unit base
by screwing them into the same threaded fittings that were used to secure the crate base to the
cabinet. Insure that the legs or casters are screwed completely into the base.

For shipping purposes, the condensing unit compressor is secured on some of the Laboratory
Freezer models. Remove the spring clips and loosen the mounting bolts prior to operation.
See the label attached to the condensing unit if applicable.

If for some reason the doors are not squared up on the cabinet, the doors can be adjusted. Opening
the door(s) and loosening the screws that hold both the top and bottom hinges to the cabinet can
accomplish this. After adjusting the door so that it is aligned correctly, tighten the screws to securely
hold the hinges in place.

VAPORIZER INSTALLATION

The Extra Low Temperature Freezers require the installation of the condensate vaporizer, which is
shipped inside the unit compartment. The vaporizer should be mounted to the cabinet bottom.
Reference View 1. In lieu of the vaporizer, these units can be plumbed to a floor drain following
local plumbing codes. For those models equipped with a hot gas vaporizer, field installation is not
required.

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Note: Disconnect power prior to installation.

1. Connect the power cord to the vaporizer and
place it in the vaporizer bracket.

2. Attach the vaporizer bracket to the back of the
unit using the four screws as shown, making sure
the plastic drain tube is in the vaporizer pan.

LOCATION

The refrigeration system located at the top of the
cabinet requires free air access for proper operation.
Allow a minimum four (4) inch clearance on the top,
rear, and sides of the cabinet. The cabinet should
also be leveled when it is placed in its permanent
location. Refer to the serial tag for complete physical
specifications.

View 1

ELECTRICAL

Check the proposed outlet to be used to insure that the voltage, phase, and current carrying
capacity of the circuit from the electrical panel correspond to the requirements of the cabinet.
NEVER use an extension cord to wire any unit. On permanently connected units, those not
furnished with a plug-in service cord, all inter-wiring between the electrical panel and the unit must
be done in accordance with the National Electric Code and all state and local codes. Refer to the
serial tag for all pertinent electrical information.

Observe all Warning Labels. Disconnect power supply to eliminate injury from electrical
shock or moving parts when servicing equipment.

GENERAL OPERATION

The laboratory refrigerators and freezers employ a unit cooler evaporator located inside the cabinet
as the heat removing source. Through the refrigeration process, heat is captured in the evaporator,
transferred to the condensing unit on top of the cabinet, and expelled to the surrounding outside air.
It is extremely important to allow a four (4) inch clearance on the top, rear, and sides of the unit for
the refrigeration process to function properly.

These refrigerators and freezers utilize a programmable controller to control the temperature and
defrost settings. The controller, which is located on the facade of the unit, is factory set. Please see
the default settings sheet and separate instructions that are included on the operation of this
controller.

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REFRIGERATORS

During the operation of a refrigerator, frost will periodically form on the coil surface. Each time the
compressor cycles "off", the evaporator fans will continue to run, which will keep the internal
temperature uniform and at the same time remove any frost build up on the coil. The water
produced will collect in the unit cooler drain pan and travel down the drain tube to the condensate
vaporizer.

FREEZERS

After shutting the door on freezer models, a short amount of time must be allowed before the door
can be reopened. This is due to the tight seal maintained between the door and the cabinet. Waiting
a few moments for the pressure to equalize permits the door to be opened easily.

A positive defrost is required to remove frost from the coil in freezer models. This is accomplished
by energizing heaters during the defrost cycle that are positioned on the coil surface. The
programmable controller is factory set to allow four defrosts per day.

As the preset defrost time is reached, the controller automatically terminates the refrigeration
process by turning off the condensing unit and unit cooler fan motors, and energizes the defrost
heaters. As the coil temperature increases, the frost begins to melt producing water that runs down
the coil to the unit cooler drain pan and exits through the drain tube to the vaporizer. After all the
frost has been removed and the coil temperature reaches approximately 50°F, the defrost is
terminated through the action of the defrost termination control located on the unit cooler, and the
refrigeration process resumes. In order to insure that any excess water remaining on the coil is not
sprayed into the cabinet interior, and all heat generated by the defrost is removed, the unit cooler

fans will not operate until the coil temperature reaches approximately 25°.

GENERAL MAINTENANCE

PERIODIC CLEANING

Beginning with the initial installation, the interior surfaces of the cabinet should be periodically
wiped down with a solution of warm water and baking soda. This solution will remove any odors
from spillage that has occurred. The exterior of the cabinet should also be cleaned frequently with a
commercial grade glass cleaner.

Monthly cleaning of the condenser will aid the heat transfer characteristics of the refrigeration
system and increase its efficiency. Dust, dirt, and lint will tend to accumulate on the fins of the
condensing unit. This obstruction will affect the flow of air through the condenser, thereby lowering
the efficiency of the system. A wire brush or a brush with stiff bristles can be used to loosen these
particles that are attached to the fins so that they may be removed with a vacuum cleaner. Failure

to keep the condenser coil clean and clear of obstructions could result in temperature loss
and damage to the compressor.

All moving parts have been permanently lubricated and will generally require no maintenance.

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MAINTENANCE SERVICE AND ANALYSIS GUIDE

REFRIGERATION SYSTEMS - ALL MODELS

MALFUNCTION POSSIBLE CAUSE SOLUTION

Compressor will not start - 1. Service cord unplugged 1. Plug in service cord
no hum 2. Fuse blown or removed 2. Replace fuse

3. Overload tripped 3. Determine reasons and correct

4. Control stuck open 4. Repair or replace

5. Wiring incorrect 5. Check wiring against the diagram

Compressor will not start - 1. Improperly wired 1. Check wiring against the diagram
hums but trips on overload 2. Low voltage to unit 2. Determine reason and correct
protector 3. Starting capacitor defective 3. Determine reason and replace

4. Relay failing to close 4. Determine reason, correct or replace

Compressor starts and runs, 1. Low voltage to unit 1. Determine reason and correct
but short cycles on overload 2. Overload defective 2. Check current, replace overload protector
protector 3. Excessive head pressure 3. Check ventilation or restriction in
refrigeration system

4. Compressor hot-return gas hot 4. Check refrigerant charge, fix leak if

necessary
Compressor operates long 1. Short of refrigerant 1. Fix leak, add refrigerant

or continuously 2. Control contact stuck 2. Repair or replace

3. Evaporator coil iced 3. Determine cause, defrost manually

4. Restriction in refrigeration 4. Determine location and remove restriction

system

5. Dirty condenser 5. Clean condenser

Compressor runs fine, but 1. Overload protector 1. Check wiring diagram
short cycles 2. Cold control 2. Differential too close - widen

3. Overcharge 3. Reduce charge

4. Air in system 4. Purge and recharge

5. Undercharge 5. Fix leak, add refrigerant

Starting capacitor open, 1. Relay contacts stuck 1. Clean contacts or replace relay
shorted or blown 2. Low voltage to unit 2. Determine reason and correct

3. Improper relay 3. Replace

Relay defective or burned out 1. Incorrect relay 1. Check and replace

2. Voltage too high or too low 2. Determine reason and correct

Refrigerated space too warm 1. Control setting too high 1. Reset control

2. Refrigerant overcharge 2. Purge refrigerant

3. Dirty condenser 3. Clean condenser

4. Evaporator coil iced 4. Determine reason and defrost

5. Not operating 5. Determine reason, replace if necessary

6. Air flow to condenser or 6. Remove obstruction for free air flow

evaporator blocked
Standard temperature system 1. Control setting is too low 1. Reset the control

freezes the product 2. Control points stuck 2. Replace the control
Objectionable noise 1. Fan blade hitting fan shroud 1. Reform or cut away small section of shroud

2. Tubing rattle 2. Locate and reform

3. Vibrating fan blade 3. Replace fan blade

4. Condenser fan motor rattles 4. Check motor bracket mounting, tighten

5. General vibration 5. Compressor suspension bolts not loosened

on applicable models - loosen them

6. Worn fan motor bearings 6. Replace fan motor

Pan Area 1. No cooling 1. Make sure switch is in the "on" position

2. Too cold 2. Adjust temperature control - see instructions

under pan area

3. Too warm 3. Adjust temperature control - see instructions

under pan area

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