SB-110-4
52
• Avoid refrigerant migration from the high-pressure
side to the low-pressure side or into the compressor
during long shut-off periods!
– Always maintain oil heater operation when the
system is at standstill. This is valid for all applica-
tions.
When installing the system in zones where the
temperatures are low, it may be necessary to in-
sulate the oil separator. At compressor start, the
oil temperature, measured under the oil sight
glass, should be 15 .. 20 K above the ambient
temperature.
– Automatic sequence change for systems with sev-
eral refrigerating circuits (approximately every 2
hours).
– Mount an additional check valve in the discharge
gas line if no temperature and pressure compens-
ation is reached even after long standstill times.
– If needed, mount a time and pressure-dependent
controlled pump down system or suction side suc-
tion accumulators – particularly for high refrigerant
charges and/or when the evaporator may become
hotter than the suction gas line or the compressor.
• For further information about pipe layout, see
manual SH-110.
Information
In the case of refrigerants with low isentropic ex-
ponent (e.g. R134a), a heat exchanger between
the suction gas line and the liquid line may have
a positive effect on the system's operating mode
and coefficient of performance.
Arrange the temperature sensor of the expan-
sion valve as described above.
7
Operation
7.1
Regular tests
Check the system at regular intervals according to na-
tional regulations. Check the following points:
• Operating data, see chapter Operation, page 52.
• Oil supply, see chapter Operation, page 52.
• Safety and protection devices and all components
for compressor monitoring (check valves, discharge
gas temperature limiters, differential oil pressure
switches, pressure limiters, etc.).
• Tight seat of electrical cable connections and
screwed joints.
• Screw tightening torques.
• Check refrigerant charge.
• Tightness test.
• Update data protocol.
8
Maintenance
8.1
Use of flammable refrigerants of safety group
A2L
• When replacing components, only use identical ori-
ginal parts from the manufacturer.
• Seals must only be replaced with original parts.
WARNING
Danger due to toxic combustion residues in
case of insufficient ventilation in the device!
Clean the filter mat at the front of the switch
cabinet regularly or replace it.
Information on maintenance and repair when using A2L
refrigerants, see A-541 (HTML)
• When carrying out maintenance work that requires
an intervention in the refrigerating circuit, stop the
power supply of the system.
• When adding or extracting refrigerant, avoid penetra-
tion of air into the system or the refrigerant bottle and
formation of ignitable blends.
WARNING
Danger due to toxic combustion residues in
case of fire!
Do not inhale combustion gases.
When extinguishing the fire, observe the inform-
ation on the safety data sheet of the refrigerant.
8.2
Arranging for removal clearances
When installing the compressor in the system, arrange
for sufficiently large clearances for removal and main-
tenance:
• HS.95: for dismantling the slider maintenance ac-
cess cover to replace the entire slider unit, provide a
minimum clearance of 70 mm for unscrewing the
screws forward!
• HS.85: in front of the oil filter chamber, for replace-
