Compressor and accessories

This chapter describes the additional residual risks posed by the condensing compressor when using A3 safety group refrigerants and provides explanations. This information helps the system manufacturer carry out the required risk assessment of the system. The information alone can in no way replace the risk assessment for the system.

Design, maintenance and operation of refrigeration systems using flammable refrigerants of the safety group A3 are subject to particular safety regulations.

When installed according to the Operating Instructions, the compressors for R290 and R1270, including the fitted accessories, are, in normal operation without malfunction, free of ignition sources that may ignite the flammable refrigerants. They are considered technically tight. In their basic version, the compressors and, if applicable, the additional fan must not be operated in an ignitable atmosphere. Operation in an Ex zone requires special Ex designs that include a suitable electrical system and approval.

The separately supplied components, such as additional fan and compressor protection device, are not free of ignition sources. They must not be operated in an ignitable atmosphere.

The following description includes only components affected by the safety regulations. Otherwise, the above-mentioned regulations shall apply.

• Electrical terminal box
• The terminal box has at least the enclosure class IP54. The protection device must not be installed in the terminal box of the compressor.
• Compressor protection devices
• Semi-hermetic reciprocating compressors: SE-B*
• Screw compressors: SE-E* or SE-i1
• Scroll compressors: SE-E4, SE-G4 or SE-B*

The protection device is delivered in each case as a separately packaged item and must be installed in the switch cabinet or a separate terminal box.

Schematic wiring diagrams for the connection of the compressor protection devices can be found in the Technical Information AT-300 (HTML).

When installing the protection devices for screw compressors and scroll compressors in the switch cabinet, observe the following:

• Connect cables to the motor connecting pins in the following order:
• black cable to 1 for screw compressors or L1 for scroll compressors
• brown cable to 2 for screw compressors or L2 for scroll compressors
• blue cable to 3 for screw compressors or L3 for scroll compressors
• Check with a rotating field measuring device!

• Additional fuses (500 mA) must be installed in the connecting cables of the protection device leading to the motor pins 1/2/3 for screw compressors or L1/L2/L3 for scroll compressors.

• Danger of induction! Only shielded or twisted cables must be used for the connection to the motor and oil PTC.

• Terminals T1-T2 with screw compressors or M1-M2 with scroll compressors on compressor and 1-2 on SE-B* and SE-E* as well as 1-8 on SE-C1 must not come into contact with control or operating voltage.

• Use of external frequency inverters (FI), for example, BITZER VARIPACK frequency inverter for speed control
• Install the FI in the switch cabinet. Use shielded cables between FI and compressor and metallic screwed cable glands.
• Do not use BITZER VARIPACK frequency inverters in an ignitable atmosphere!
• Start unloading / Capacity control / Oil heater / Additional fan for semi-hermetic reciprocating compressors
• Available as optional accessories. They have at least enclosure class IP54 (exception: with additional fan for 2KESP .. 2CESP: enclosure class IP44).
• Differential oil pressure switch / Oil level monitoring
• Electronic oil level monitoring OLC-K1 (compressor series CE3 / CE4S), electronic differential oil pressure switch Delta P-II (compressor series BE5 / BE6 / CE8) and optoelectronic oil level monitoring OLC-D1-S (compact screw compressor CSH/CSW) and OLC-D1-D (oil separator for screw compressors) are available as optional accessories. They are designed in enclosure class IP54 or higher.
• Pressure relief valve
• Reciprocating and screw compressors for R290 and R1270 are equipped as standard with an internal back-pressure-dependent pressure relief valve.
• Safety devices for limiting the pressure
• Safety pressure cut-outs for protection against excessive pressure must be designed and used in accordance with the requirements of the safety regulations (e.g. EN 378- 2).
• A pressure limiter to protect against too low pressure is also recommended. It should be set such that vacuum operation is reliably prevented. In the event of leakage, air could be sucked in and lead to an ignitable mixture with the refrigerant. The risk assessment of the compressors only includes operation above ambient pressure.

• Marking
• Description, Marking of the propane/propene compressors.