Blue Box SIGMA 2002 - External Interlock; Microprocessor Controllers

Blue Box - 47
4.16.5 Circulating pump electrical connections
The external interlocks of unit must close for the unit to operate. The normally open external water circulating
pump contactor terminals must be wired in series with terminals 1 and 2, on the unit control panel, to ensure that
the chiller can only start after the pump is in operation.
Turn on the pump before the unit starts and stop it after the unit has
stopped (recommended time delay: 60 sec).
4.16.3 Potential free contacts
The following potential free contacts are available:
- 1 potential free contact for general alarm (terminals 100 - 101 - 102)
- 1 potential free contact for each compressor (option)
4.16.4 Flow switch electrical connections
Flow switch electrical connections (see paragraph 4.5 ) must be connected to terminal 1-14 for chiller units.
For heat pump units evaporator (user exchanger) flow switch must be connected to terminals 1-15 while condenser
(source exchanger) flow switch must be connected to terminals 14-15.
4.16.6 External interlock
If a remote ON-OFF is required connect the external interlock to terminals 1 and 2. If an external interlock is not
required, bridge therminals 1 and 2 to enable the unit to start.
4.16.2 Power supply to crankcase heaters
1) Close the main disconnect switch by turning it from position "0" to position "1"
2) Check that the word "OFF" is shown on the display
3) Ensure that the unit is in "OFF" status and that the external enabling contact is open
4) After a few moments, if the phase sequence is incorrect the alarm "INCORRECT PHASE SEQUENCE" will be
displayed (4-compressor models from 14.4 to 26.4 only, with pCO
2
controller). In this case invert the connections
of two of the power line phase wires.
5) Leave the unit in this condition for at least 12 hours to allow the crankcase heaters to perform their function
4.17 MICROPROCESSOR CONTROLLERS
Chillers in the SIGMA 2002 series with 2 scroll compressors, models from 3.2 to 13.2, are equipped with the
mCHILLER type microprocessor controller.
Chillers in the SIGMA 2002 series with 4 scroll compressors, models from 14.4 to 26.4, are equipped with the
pCO
2
microprocessor controller.