Kelvinator R-404A Installation Manual Download

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SECTION III

MAINTENANCE & REPAIR

MAINTENANCE & REPAIR

TOOLS:

To provide full service diagnostics and repairs on
these cabinets the following tools are needed:

A Volt Meter

An Amp Meter

An Ohm Meter or tiplet meter to handle all three functions

An Electronic Leak Detector

An Electronic Micron Gauge

A Vacuum Pump capable of pulling to 50 microns

Four Hand Valves

A Refrigerant Reclaimer

A Compound Gauge Set

A cylinder of nitrogen with a regulator capable of 10 to
400 pounds.

Standard refrigeration hand tools like: wrenches,
tubing cutter, swage and flare tools, wire strippers,
wire crimpers, wire cutters, standard and phillips head
screwdrivers.

PRODUCT HISTORY

The first rule in accurately servicing a refrigeration
system is to determine if the problem is an electrical
or mechanical failure within the refrigeration system.
First, try to obtain the product’s history of operation
from the customer. This will help identify the source of
the problem.

Good facts from the cabinet user can help identify
whether the problem is electrical, within the
refrigeration system, or a “misapplication by the user.”
Get the history of operation and failure by asking
these questions:

1) Were there any brown-outs or power outages that

they are aware of?

2) Is the cabinet on a dedicated circuit?

3) Has any other equipment in this area had

operational problems?

4) When was the last time the cabinet’s operation was

confirmed as working properly?

5) When was a problem noticed?

6) How long has the equipment run without this

problem? (Years? Weeks? Days? Hours?)

7) Was anything tried prior to your arrival?

8) Was the warm-up fast, as in three to six hours, or

over a prolonged time, as in three to five days?

9) If the cabinet was running for a long time, was the

temperature recovery after entering the cabinet
always within an hour, or did it appear as though
recovery time was longer as usage went on?

The refrigeration system should only be entered if it is
absolutely necessary. It is critical that a clean,
uncontaminated system be maintained.

If a system is unable to reach the proper operating
temperature, a test of the unit’s mechanical
refrigeration components is required.

COMPRESSOR EFFICIENCY TEST

If the cabinet has a semi-hermetic compressor, begin
by testing the compressor’s efficiency.

To test a semi-hermetic compressor, place compound
gauge on the compressor’s suction port.

While the compressor is running, close off the suction
line so that only the port and valve are part of the
compressor’s low side.

When the valve is closed and vacuum has started,
time how long it takes to pull the compressor’s low
side to its lowest possible vacuum.

Compressors used on these cabinets should be
capable of pulling at least 20 to 22 inches of vacuum
in less than 40 seconds.

Next, shut off the compressor and watch the gauge. A
one or two inch rise in pressure is acceptable, since a
small amount of freon may remain on the low side of the
compressor, after which the reading should stabilize.

If the pressure continues to rise, the discharge reeds
in the valve head are bad, allowing high pressure gas
to return to the compressor.

If the compressor pulls less than 20 inches, the
suction reeds are bad in the valve head.

If it takes longer than 40 seconds to pull the
compressor, to its ultimate low vacuum, one or both
cylinders are not functioning as they should. Any
reading less than these will require replacement of the
compressor.

Dipping Cabinet 1298.02 2/3/03 1:14 PM Page 32