Webasto BCT010300C Repair Manual download pdf (Page 33)

Troubleshooting – Refrigerant Compressor

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6.4 Identifying Compressor Electrical

Problems

This section describes procedures for checking the

compressor’s electrical circuits and components. Before

doing so, follow the BlueCool Truck System service

information under “Troubleshooting – BlueCool Truck

Electrical System” starting on page 14 to make sure the

system is getting proper voltage and that the digital

temperature sensor, control module, and relays are

working properly.

Whenever you suspect that there is an electrical problem

with the compressor (for example, there has been a

tripped circuit breaker):

• FIRST, check for a ground fault (also known as a

short circuit to ground) in the motor using a

megohmmeter (“megger”) or a Hi-Potential

Ground Tester (“Hi-Pot”) (Section 6.4.1).

• SECOND, check the motor windings for proper

continuity and resistance (Section 6.4.2).

• THIRD, check the compressor’s electrical

components (Section 6.4.3).

When checking for electrical problems, it is important to

follow all safety precautions (see warning below) and use

the proper equipment and procedures.

Oil and refrigerant can spray out of the

compressor if one of the terminal pins is

ejected from the hermetic terminal.

This can occur as a result of a ground fault in the

compressor. The oil and refrigerant spray can be ignited

by electricity and produce flames that can lead to serious

burns or death. If this spray is ignited it is called

“terminal venting with ignition”.

To reduce the risk of electrocution, serious burns or death

from terminal venting with ignition:

• Disconnect ALL electrical power before removing

the protective terminal cover.

• Never energize the system unless:

• the protective terminal cover is securely

fastened, and

• the compressor is properly connected to

ground.

• Never reset a breaker or replace a fuse without first

checking for a ground fault. An open fuse or

tripped circuit breaker is a strong indication of a

ground fault.

• Be alert for sounds of arcing (sputtering or

popping) inside the compressor. If you hear these

sounds, IMMEDIATELY move away from the area

of the compressor.

Unit runs OK, but run cycle

is shorter than normal (due

to component (s) other

than thermal protector)

System components, such as digital temperature sensor,

control module, relays, not functioning properly.

Refer to the BCT “Troubleshooting - BlueCool Truck

Electrical System” starting on page 14.

High pressure cut-out due to:

a. Insufficient air or coolant supply.

b. Overcharge or refrigerant.

c. Air in system.

Refer to the BCT service information.

Same as “a”.

Low pressure cut-out due to:

a. Refrigerant leaking.

b. Undercharge of refrigerant.

c. Restriction in Thermal Expansion Valve.

Refer to the BCT service information.

Same as “a”.

Unit operates long or

continuously

Undercharge of refrigerant. Refer to the BCT service information.

System components, such as digital temperature sensor,

control module, relays, not functioning properly.

Refer to the BCT service information.

Restriction in refrigeration circuit. Refer to the BCT service information.

Dirty condenser. Refer to the BCT service information.

System rattles or vibrates

during operation.

Loose parts or mountings, tubing rattle, bent fan blade

causing vibration, fan motor bearings worn, etc.

Refer to the BCT service information.

Table 9. Troubleshooting Table – Refrigerant Compressor and Related Components

Symptom Possible Causes Remedy

WARNING

1 2 ... 28 29 30 31 32 33 34 35 36 37 38 ... 53 54

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