Compressor Start; Checking The Rotation Direction; Lubrication/Oil Level Monitoring; Set High Pressure And Low Pressure Switches (Hp + Lp) - Bitzer CSH6553-35Y Operating Instructions Manual

When a reciprocating compressor is replaced:
▶ Completely remove the oil from the system. The new
oil is not only more viscous. It is an ester oil with dif-
ferent chemical and physical properties.
NOTICE
!
!
Risk of damage to the compressor!
The new oil has a great cleaning effect in the re-
frigerant circuit.
On the suction side, mount a cleaning filter suit-
able for bidirectional operation!
Mesh size: 25 µm
• Mount a filter for bidirectional operation with perfor-
ated metal tubes around the inside and outside dia-
meter of the filter element.
▶ After several operating hours: Change the oil filters
and cleaning filters.
▶ If needed, repeat the operation, see chapter Oil
change, page 75.

4.6 Compressor start

4.6.1

Checking the rotation direction

NOTICE
!
!
Risk of compressor failure!
Operate the compressor only in the intended ro-
tation direction!
Even if the protection device SE-E1 or the optional pro-
tection device SE-i1 monitors the rotating field, a test is
recommended:
Rotation direction test with integrated suction shut-off
valve:
• Connect the pressure gauge to the suction shut-off
valve. Close the valve spindle and open again by
one turn.
• Let the compressor start shortly (approximately 0.5 ..
1 s).
• Correct rotation direction: Suction pressure drops im-
mediately.
• Incorrect rotation direction: Suction pressure in-
creases or protection device shuts off.
▶ Incorrect rotation direction: Change the poles of the
terminals on the common power supply line.
Direction rotation test without suction shut-off valve:
• Close the solenoid valves on the evaporator and the
economiser. The pressure changes measured in
48
such a case are much lower than with throttled suc-
tion shut-off valve!
• Let the compressor start shortly (approximately 0.5 ..
1 s).
• Correct rotation direction: Suction pressure drops a
bit.
• Incorrect rotation direction: Suction pressure stays
the same or increases a bit, or protection device
shuts off.
▶ Incorrect rotation direction: Change the poles of the
terminals on the common power supply line.
After the rotation direction test:
▶ Let the compressor start while opening slowly the
suction shut-off valve.
4.6.2

Lubrication/oil level monitoring

▶ Check the lubrication of the compressor directly after
the compressor start.
➙ The oil level must be visible in the zone of both sight
glasses.
▶ Check the oil level repeatedly within the first hours of
operation!
➙ During the start phase, oil foam may arise but its
level should decrease at stable operating conditions.
Otherwise high proportions of liquid in the suction
gas are suspected.
NOTICE
!
!
Risk of wet operation!
Maintain the discharge gas temperature well
above the condensing temperature: at least
20 K.
At least 30 K for R407A, R407F and R22.
NOTICE
!
!
Risk of compressor failure due to liquid slug-
ging!
Before adding larger quantities of oil: check the
oil return!
4.6.3 Set high pressure and low pressure
switches (HP + LP)
Check exactly the cut-in and cut-out pressure values
according to the operating limits by testing them.
4.6.4

Set the condenser pressure

▶ Set the condenser pressure so that the minimum
pressure difference is reached within 20 s after the
compressor start.
SB-170-10