Bard MIS-656 installation instructions Wiring - Low Voltage Wiring, Table Operating Voltage Range

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:

TABLE 4

OPERATING VOLTAGE RANGE

TAP	RANGE
240V	253 – 216
208V	220 – 187

NOTE: The voltage should be measured a the field power connection point in the unit and while the unit is operating at full load (maximum amperage operating condition.)

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 10.

TABLE 5

THERMOSTAT WIRE SIZE

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

TABLE 6

WALL THERMOSTAT AND SUBBASE COMBINATIONS

Thermostat	Subbase	Predominate Features
8403-002	8404-003	1 stage heat, 1 stage cool
T87F3111	Q539A1220	System: heat-off-cool	Fan: auto-on
8403-041	---	1 stage heat, 1 stage cool
T8034C		System: heat-off-cool	Fan: auto-on
8403-019	8404-012	1 stage cool, 2 stage heat
T874C1760	Q674A1001	System: heat-auto-cool	Fan: auto-on
8403-021	8404-012	2 stage cool, 2 stage heat
T874D1934	Q674A1001	System: heat-auto-cool	Fan: auto-on
8403-049	---	2 stage cool, 2 stage heat
1F93-380		Electronic 7 day programming w/ventilation control
8403-043	---	1 stage heat, 1 stage cool
CM-200		System: heat-off-cool	Fan: auto-on

Manual 2100-404 Page 7