Heatcraft H-IM-QRC, Installation And Operation Manual, Page: 4 / 40

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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 Heatcraft Quick Response Controller 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 Heatcraft Quick Response Controller systems,the main power
for the evaporator is supplied separately from the power supply of
the condensing unit. All wiring, however, must comply with local
electrical codes.
Installation
Wiring
Wiring at 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 is connected to a separate
power supply from the condensing unit.
See unit cooler spec. plate for ampacity.
• Low voltage wiring must be 18 gauge
minimum. For low voltage wiring, maximum
distances are:
Between evaporators 500 ft.
• Multiple units – The multi-in and multi-out
are the communication connections.
Connection sequence must follow the multi-
out terminal to the multi-in terminal and
the multi-out back to the multi-in terminal in
a daisy chain loop.
• Alarm circuit - The onboard alarm is a dry set of NC
contacts which closes to indicate an alarm or loss of
power. The type and wiring for the alarm is customer
specified. Note that the alarm circuit does not distinguish
or indicate what has caused the alarm.These contacts can
handle up to a 2 Amp load.
• All wiring must comply with all applicable codes and
ordinances.
Refrigerant Line Brazing (Caution)
CAUTION:
All 24v wiring must be run separate from the line
voltage wiring. Wires/Leads must not touch other component
connection points or power wires to avoid damage to the
board or its components.