Bard WH301D Installation Instructions Manual Download Page 13

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Manual 2100-357
Page 11

WIRING — MAIN POWER

Refer to the unit rating plate for wire sizing information
and maximum fuse or “HACR" type circuit breaker
size. Each outdoor unit is marked with a “Minimum
Circuit Ampacity”. This means that the field wiring
used must be sized to carry that amount of current.
Depending on the installed KW of electric heat, there
may be two field power circuits required. If this is the
case, the unit serial plate will so indicate. All models are
suitable only for connection with copper wire. Each unit
and/or wiring diagram will be marked “Use Copper
Conductors Only”. These instructions must be adhered
to. Refer to the National Electrical Code (NEC) for
complete current carrying capacity data on the various
insulation grades of wiring material. All wiring must
conform to NEC and all local codes.

The electrical data lists fuse and wire sizes (75ºC
copper) for all models, including the most commonly
used heater sizes. Also shown are the number of field
power circuits required for the various models with
heaters.

The unit rating plate lists a “Maximum Time Delay
Relay Fuse” or “HACR" type circuit breaker that is to
be used with the equipment. The correct size must be
used for proper circuit protection and also to assure that
there will be no nuisance tripping due to the momentary
high starting current of the compressor motor.

The disconnect access door on this unit may be locked
to prevent unauthorized access to the disconnect. To
convert for the locking capability, bend the tab located
in the bottom left hand corner of the disconnect opening
under the disconnect access panel straight out. This tab
will now line up with the slot in the door. When shut, a
padlock may be placed through the hole in the tab
preventing entry.

WIRING — LOW VOLTAGE WIRING

230/208V, 1 phase and 3 phase equipment dual primary
voltage transformers. All equipment leaves the factory
wired on 240V tap. For 208V operation, reconnect from
240V to 208V tap. The acceptable operating voltage
range for the 240 and 208V taps are:

LOW VOLTAGE CONNECTIONS

These units use a grounded 24 volt AC low voltage
circuit.

The "R" terminal is the hot terminal and the "C"
terminal is grounded.

"G" terminal is the fan input.

"Y" terminal is the compressor input for cooling.

"B" terminal is the reversing valve input. The reversing
valve must be energized for heating mode.

"R" terminal is 24 VAC hot.

"C" terminal is 24 VAC grounded.

"L" terminal is compressor lockout output. This
terminal is activated on a high or low pressure trip by
the electronic heat pump control. This is a 24 VAC
output.

"W2" terminal is second stage heat (if equipped).

"O1" terminal is the ventilation input. This terminal
energizes any factory installed ventilation option.

"E" terminal is the emergency heat input. This terminal
energizes the emergency heat relay.

"W3" terminal is the 24 VAC dehumidification circuit.

"W1" terminal is the compressor input of heat pump
heating.

NOTE: For total and proper control using DDC, a total

of 8 controlled outputs are required (7 if no
ventilation system is installed). For proper
system operation under Emergency Heat
conditions where the compressor needs to be
deactivated, the B-W2-E outputs need to be
energized. Removing the W1 (compressor)
signal alone turns the compressor off, but does
not activate the additional circuitry embedded
in the heat pump for proper and complete
operation.

NOTE: The voltage should be measured at the field

power connection point in the unit and while
the unit is operating at full load (maximum
amperage operating condition).

Nine (9) wires should be run from thermostat subbase to
the 24V terminal board in the unit. A nine conductor, 18
gauge copper, color-coded thermostat cable is
recommended. The connection points are shown in
Figure 7 and 8.