DB-309-3
19
5.1
Oil thermostat
Do not operate the system without oil thermostat!
During standstill, the oil thermostat (see chapter Mount-
ing, page 16, "Simple electrical equipment") switches
the oil heater on if the oil temperature in the oil separ-
ator drops below the setpoint.
• Adjust the setpoint to 60°C (or at least to a value 20
K above the maximum ambient temperature)
• Incorporate the oil thermostat into the intrinsically
safe circuit according to the schematic wiring dia-
gram.
DANGER
Risk of explosion due to an incorrectly connec-
ted oil thermostat!
Only use an oil thermostat which is suitable for
the use in a potentially explosive atmosphere
and connect it together with the section switch
amplifier!
5.2
Oil heater
Observe the information in the operating instructions of
the heater manufacturer!
During standstill of the system, the oil heater prevents
back condensation of the refrigerant into the oil separ-
ator. It may only be switched on if the heater element is
completely covered with oil. Therefore, it is electrically
locked by the oil level switch (see schematic wiring dia-
gram in the Operating Instructions SB-509). During
standstill of the system, the function of the heater must
be ensured if the oil temperature in the oil separator
drops below the set point of the oil thermostat.
The heating capacity is set to such a value that the
maximum permitted surface temperature cannot be ex-
ceeded. The oil heater for models OA4188(A)-EX to
OA25112(A)-EX has an additional integrated temperat-
ure limiter and a temperature controller.
• Connect the oil heater according to the schematic
wiring diagrams indicated in the Operating Instruc-
tions SB-509.
DANGER
Risk of explosion due to an incorrectly mounted
oil heater!
Only use the oil heater approved by BITZER
and authorised for the use in potentially explos-
ive atmosphere!
Temperature limiter of the oil heater for OA4188(A)-
EX to OA25112(A)-EX
• Break point 100°C.
• Manual fault reset:
– Remove the oil heater cover.
– Press the button (see figure 6, page 19, position
1).
– Carefully screw on the oil heater cover again. Ob-
serve the information in the operating instructions
of the heater manufacturer!
Temperature controller of the oil heater for
OA4188(A)-EX to OA25112(A)-EX
• Remove the oil heater cover.
• Adjust the set point at the setting wheel to 60°C (or
at least to a value 20 K above the maximum ambient
temperature). see figure 6, page 19, position 2.
• Carefully screw on the oil heater cover again. Ob-
serve the information in the operating instructions of
the heater manufacturer!
3
2
1
Fig. 6: Oil heater for OA4188(A)-EX..OA25112(A)-EX, the dark-grey
parts are located underneath the cover
1
Press-button for manual fault reset of the tem-
perature cut-out
2
Set knob for setting the temperature on the
temperature regulator
3
Terminal cover
