Compressor - Bosch ACS 561 Repair Instructions

ACS 561 Service Manual
Compressor Troubleshooting
1. Check for proper power source, circuit
breaker, and electrical connectors for dam-
age or corrosion.
2. Connect the unit directly to a known good
power source. Do not use an extension
cord.
3. Verify the ground wire between the com-
pressor electrical box and chassis ground
is securely fastened.
4. Check for 220VAC to the compressor.
• If there is no voltage to the compressor's
start components, proceed to the next
step.
• If voltage is present at the compressor,
replace the compressor thermal protector
and start relay assembly. If compressor
runs, verify the compressor amp draw is
within specs. If the compressor doesn't
run and/or is drawing locked rotor amps,
replace the compressor.
If using the output step test to run com-
pressor, the oil return solenoid must be
open before the compressor is started.
5. Check for 220VAC from the power board on
connector P4, pins 1 and 2.
When checking voltage to the compres-
sor it is normal to read low voltage at the
connector when it's disconnected and
the power to the compressor is off.
• If voltage is present, check wiring be-
tween the power board and the compres-
sor start components. Repair as needed.
• If voltage is not present, replace the relay
board.
6. Perform functional check.
Compressor Testing Procedure
1. Remove shrouding from the unit.
2. Close tank valve and depressurize the unit
in accordance to the service manual.
3. Remove all 3 lines attached to the compres-
sor.
The discharge line will be under pres-
sure.
4. Cap off the compressor oil return port.
Robert Bosch GmbH
Diagnostics and Testing

Compressor

Figure 2-1. Compressor Assembly
5. Connect a manifold set to the compressor,
high side to the compressor discharge and
the low side to the suction port. Remove
hose from center port of manifold.
6. Close both valves on the manifold.
7. Enter the service menu, scroll to the output
test and select the compressor test.
8. Start the compressor.
9. The first time the compressor is tested, the
gauges may read approximately 7 bar (100
psi) and 540 mBar (16 in-Hg).
10. Turn off the compressor and release pres-
sure from manifold.
Test the Compressor a Second Time
Studies have shown the first test may
give false compressor values due to
imbedded refrigerant in the oil.
1. Close the valves on the manifold and start
the compressor.
2. A good compressor will produce 14 bar (200
psi) discharge and 472 mBar (14 in-Hg) on
the suction side, minimum.
3. Repeat the test a third time to verify read-
ings.
4. If the suction or discharge of the compres-
sor is under specifications, replace the
compressor.
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SP00D00517 2018-07-11