Webasto BCT010300C Repair Manual download pdf (Page 38)

Compressor Replacement and System Service

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7. Compressor Replacement and

System Service

7.1 System Cleanup and Compressor

Replacement After Compressor

Failure

Once you determine that a compressor needs to be

replaced you must then determine whether the system

has been contaminated. Compressor motor failure can

lead to such contamination. (While compressor motor

failure is sometimes referred to as motor “burnout”, it

does not mean that a fire actually occurs inside a

hermetic compressor.) Even small amounts of

contamination must be removed from the system to

avoid damaging the replacement compressor. Therefore,

it is important to thoroughly clean a refrigeration/air

conditioning system if system contamination is present.

If a compressor motor failure has

occurred, refrigerant or mixtures of

refrigerant and oil in the system can be

acidic and cause chemical burns.

As always, to avoid injury, wear appropriate protective

eye wear, gloves and clothing when servicing an air

conditioning or refrigeration system. If refrigerant or

mixtures of refrigerant and oil come in contact with skin

or eyes, flush the exposed area with water and get

medical attention immediately.

The following outlines a process for compressor

replacement and system clean-up for a system equipped

with a Tecumseh compressor. You should refer to the

original equipment manufacturers (OEM) service

information.

A. Determine Extent of System Contamination

Following the precautions in “Refrigerants and Other

Chemicals” and “Compressor Removal” on page 27,

remove the compressor.

Use the following guidelines to determine whether

contamination, if any, is limited to the compressor or

extends to the system.

If the discharge line shows no evidence of contamination

and the suctions tub is clean or has only light carbon

deposits, then the contaminants are limited to the

compressor housing (Compressor Housing

Contamination). A single installation of liquid and

suction line filter-driers should clean up the system.

If, however, the discharge line or the suction line shows

evidence of contamination, the compressor was running

at the time of the motor failure and contaminants were

pumped throughout the system (System Contamination).

If System Contamination has occurred, several changes

of the liquid and suction line filter-driers will be needed

to cleanup the system. In addition, the thermal

expansion valve will need to be replaced.

B. Install Replacement Compressor and

Components

1. Install the replacement compressor with new

external electrical components (capacitors, relay,

overload, etc., where applicable).

2. Install an oversized liquid line filter-drier.

3. Install a generously sized suction line filter-drier

immediately upstream of the compressor. The drier

when permanently installed in a clean system must

have a pressure drop not more than 2 psi, or initially

installed in a dirty system temporarily, must have a

pressure drop not more than 9 psi. Pressure taps

must be supplied immediately before and after the

suction filter-drier to permit the pressure drop to be

measured.

If a suction line accumulator is present and System

Contamination has occurred, it must be thoroughly

flushed to remove any trapped sludge and thus

prevent if from plugging the oil return hole. The

filter-drier should be installed upstream of the

accumulator and the compressor.

In case of Compressor Housing Contamination, the

filter-drier should be installed between the

compressor and the suction line accumulator.

Rubber refrigeration hoses are not satisfactory for

temporarily hooking up the suction line filter-drier to

the system since the acid quickly breaks down the

rubber and plastic.

4. Follow the Precautions in “System Flushing, Purging,

and Pressure Testing for Leaks” on page 28, to purge

the system and pressure test for leaks.

C. Evacuate the System

Evacuate the system to less than 1000 microns, using a

good vacuum pump (not a compressor) and an accurate

high vacuum gauge. Operate the pump at 1000

microns, or less, for several hours to be sure the vacuum

is maintained.

Alternate method of removing moisture and non-

condensable material from the systems is:

WARNING

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Webasto BCT010300C Repair Manual Page 38

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