Heatcraft Refrigeration Products H-IM-79B - Manual (Page 5)

5
Refrigerant Line Brazing ( CAUTION)
The electric expansion valve and the suction temperature sensor on the suction line are
factory installed. Care must be taken when brazing these lines at the evaporator.
Too high
a temperature may destroy these components. Heat absorbing compounds or “wet
rags” must be used to protect the electric expansion valve when brazing the
refrigerant line connections. The suction line sensor should be removed before
brazing.
POWER SUPPLY
The Beacon II board gets its 24 VAC power supply from a transformer mounted in the
electrical end of each evaporator. On 208-240 volt systems the multi-tap transformer is
shipped from our factory wired for 240 volts. If your supply voltage is 208 volt you must
change to the 208 volt tap on the transformer.
VERY IMPORTANT: If the supply voltage to the evaporator is 208 volts, the primary tap of
the transformer must be moved to the 208 volt tap.
This must be done for all the
evaporators on that system.
If the 24 VAC power supply falls below 18 VAC the system may power down and shut off.
When the power supply is corrected to 24 VAC the system will restart after the four minute
hold-off period and resume normal operation.
On Beacon II systems the main power for the evaporator can be supplied separately from
the power supply of the condensing unit. All wiring, however, must comply with local
electrical codes.
WIRING
Wiring between the condensing unit and the unit cooler(s) will be as follows (see wiring
diagrams):
• High voltage - There may be high voltage on the defrost heater relay and the fan relay.
The evaporator may also be connected to a separate power supply from the condensing
unit. See unit cooler spec. plate for ampacity.
• Low voltage - 24V Class II control circuit. A total of five low voltage leads are required to
connect the condensing unit to the evaporator. (See wiring diagram.) Two of these leads
are for connecting the outdoor temperature sensor. The other three leads are for
connecting the compressor relay, service relay and 24V Common inputs.
All 24 volt
wiring must be run separate from the line voltage wiring.
• Low voltage wiring must be 18 gauge minimum. For low voltage wiring, maximum
distances are:
Condensing unit to Master evaporator 500 ft.
Between evaporators 500 ft.
Smart Controller to Master evaporator 1000 ft.
Brazing