Nortek B6BM Series, Installation Instructions Manual

10

ELEctRIcAL coNNEctIoNS

 WARNING:

ELEctRIcAL SHocK, FIRE oR

EXPLoSIoN HAZARD

Failure to follow safety warnings exactly could 

result in serious injury or property damage.
Improper servicing could result in dangerous 

operation, serious injury, death or property 

damage.
Before servicing, disconnect all electrical power 

to furnace.
•  Before  servicing,  disconnect  all  electrical 

power to the air handler.

•  When servicing controls, label all wires prior 

to disconnecting. Reconnect wires correctly.

•  Verify proper operation after servicing.

•  Electrical  connections  must  be  in  compliance  with 

all applicable local codes and ordinances, and with 

the current revision of the National Electric Code  

(ANSI/NFPA 70).

•  For Canadian installations, the electrical connections and 

grounding shall comply with the current Canadian Electrical 

Code (CSA C22.1 and/or local codes).

Pre-Electrical checklist

√

 Verify the voltage, frequency, and phase of the supply 

source match the specifications on the unit rating plate.

√

 Verify that the service provided by the utility is sufficient 

to handle the additional load imposed by this equipment. 

See the unit wiring label or 

Table 11, (page 21)

 & 

Table 

12, (page 22)

 for proper MCA & MOP information.

√

 Verify factory wiring is in accordance with the unit wiring 

diagram (

Figure 19 (page 28)

, 

Figure 20 (page 29)

, & 

Figure 21 (page 30)

). Make sure the connections didn’t 

loosen during shipping or installation.

Line Voltage

• 

An electrical disconnect must be located within sight 

of and readily accessible to the unit. This switch shall 

be capable of electrically de-energizing the outdoor unit. 

See unit data label for proper incoming field wiring. Any 

other wiring methods must be acceptable to authority 

having jurisdiction.

•  It  is  recommended  that  the  line  voltage  to  the  unit  be 

supplied from a dedicated branch circuit containing the 

correct fuse or circuit breaker for the unit.

•  Overcurrent  protection  must  be  provided  at  the  branch 

circuit distribution panel and sized as shown on the unit 

rating label and according to applicable local codes. See 

the unit rating plate and 

Table 11, (page 21)

 & 

Table 12, 

(page  22)

 for maximum circuit ampacity and maximum 

overcurrent protection limits.

•  The installer should become familiar with the wiring diagram/

schematic before making any electrical connections to the 

unit. See the unit wiring label or 

Figure 19 (page 28)

, 

Figure 20 (page 29)

, & 

Figure 21 (page 30)

.

•  Use only copper wire for the line voltage power supply 

to this unit. Use proper code agency listed conduit and a 

conduit connector for connecting the supply wires to the 

unit. Aluminum supply wire may be used if a heater kit is 

installed.

•  If replacing any of the original wires supplied with the unit, 

the replacement wire must be copper wire consisting of 

the same gauge and temperature rating.

•  Provide power supply for the unit in accordance with the 

unit wiring diagram, and the unit rating plate. Use UL listed 

conduit and conduit connectors for connecting the supply 

wires to the unit and for proper grounding. Field supplied 

bushings for the power supply cables must be added to 

support and protect the power supply cables. 

•  All 208/230 Volt units are shipped from the factory wired for 

240 volt operation. For 208V operation, remove the lead 

from the transformer terminal marked 240V and connect 

it to the terminal marked 208V.

thermostat connections

•  Thermostat connections shall be in accordance with the 

instructions supplied with the thermostat. The thermostat 

used with this equipment must operate in conjunction 

with any installed accessories. Typical AC and air handler 

hookups are shown in 

Figure 13 (page 25)

.

 cAutIoN:

Isolation must be maintained from the external 

class 2 output of any transformer in a cooling 

circuit. use a thermostat with isolating contacts 

to prevent inter-connection of class 2 outputs.

•  Where local codes require that the thermostat wiring must 

be routed through a conduit or raceway, splices can be 

made inside the unit; however, all wiring must be NEC 

Class 1 and separated from incoming power leads.

•  The thermostat should be mounted about 5 feet above the 

floor on an inside wall. DO NOT install the thermostat on 

an outside wall or any other location where its operation 

may be adversely affected by radiant heat from fireplaces, 

sunlight, or lighting fixtures, and convective heat from 

warm air registers or electrical appliances. Refer to the 

thermostat manufacturer’s instruction sheet for detailed 

mounting and installation information.

•  Install the grommet, which is packed with the unit, in the 

hole for low-voltage wires. Properly connect the low-voltage 

wiring between the thermostat, outdoor unit, and control 

board. 

NotE: When the low voltage wires are positioned 

in this grommet, the grommet will prevent chafing and/or 

shorting of the low voltage leads.

Grounding

 WARNING:

the unit cabinet must have an uninterrupted or 

unbroken electrical ground to minimize personal 

injury if an electrical fault should occur. Do not 

use gas piping as an electrical ground!

This unit must be electrically grounded in accordance with 

local codes or, in the absence of local codes, with the National 

Electrical Code (ANSI/NFPA 70) or the CSA C22.1 Electrical 

Code. Use the grounding lug provided in the control box for 

grounding the unit.

control Board

The control board in the air handler controls the timing 

sequence of the elements. The board is equipped with a 3 

second blower on delay and a 15 second blower off delay in 

heating and a 40 second blower off delay in cooling.