Bard P1124A3, P1224A2 Wiring Main Power, Wiring 24V LOW Voltage Control Circuit, Transformer Taps

WIRING – MAIN POWER

Refer to the unit rating plate for wire sizing information and maximum fuse 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. If field installed heaters are added to the basic unit, a second separate power supply circuit will be required. The heater rating plate located adjacent to the basic unit rating plate will show the appropriate circuit ampacity fuse size, etc. (Also see “Electrical Specifications” on pages 3, 4 and 5.) All models are suitable for connection with copper wire only. These instructions must be adhered to. Refer to the National Electrical Code for complete current carrying capacity data on the various insulation grades of wiring material.

The electrical specifications list fuse and wire sizes (75°F copper) for all models including the most commonly used heater sizes.

The unit rating plate lists a “Maximum Time Delay 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.

WIRING – 24V LOW VOLTAGE CONTROL CIRCUIT

Five (5) wires should be run from thermostat subbase to the 24V terminal board in the unit. A five conductor, 18 gauge copper, color-coded thermostat cable is recommended. The connection points are shown in Figure 9.

TABLE 9

THERMOSTAT WIRE SIZE

			Maximum
			Distance
Transformer VA	FLA	Wire Gauge	In Feet
		20	45
		18	60
55	2.3	16	100
		14	160
		12	250

TRANSFORMER TAPS

230/208V, 1 phase and 3 phase equipment employ 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:

TAP	RANGE
240	253 – 216
208	220 – 187

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).

THERMOSTATS

See specific wiring information for the different models, heater KWs, and voltages on unit and heating wiring diagrams..

TABLE 10

WALL THERMOSTAT AND SUBBASE COMBINATIONS

Thermostat	Subbase		Predominant Features
8403-022	8403-003	1 stage heat, 1 stage cool,		Mercury
T87F3111	Q539A1220	System: Heat-off-cool		Fan: on-auto
8403-041	——	1 stage heat, 1 stage cool,		Mercury
T8034C1499		System: Heat-off-cool		Fan: on-auto
8403-049	——	2 stage heat, 2 stage cool,
1F93-380		Electronic	Programmable
8403-043	——	1 stage heat, 1 stage cool,		Mercury
CM200		System: Heat-off-cool		Fan: on-auto Snap Action
8403-048		1 stage heat, 1 stage cool,		Mercury
	——	System: Heat-off-cool		Fan: on-auto
T8400C1313
		Electronic	Non-Programmable
8403-019	8404-012	1 stage heat, 1 stage cool,		Mercury
T874C1760	Q674C1760	System: Heat-auto-cool		Fan: on-auto

IMPORTANT NOTE: Only the thermostat and subbase combinations as shown above will work with this equipment. The thermostat and subbase MUST be matched, and correct operation can be assured only by proper selection and application of these parts.

Manual 2100-353

Page 15