Nortek B6BV Series, Installation Instructions Manual

9

•  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. See 

Figure 11 (page 19)

 or 

Figure 12 (page 

19)

. for control board layout and 

Table 8 (page 15)

for element sequences.

twinning

These instructions are to be used when connecting two 

B5 or B6 air handlers (2-5 ton models) to a common 

single stage A/C condensing unit or heat pump. Twinning 

is possible for B5 units with PSC or X-13 motors and B6 

units with PSC or fixed speed (FSHE) motors. Twinning 

is not possible for units with variable (VSHE) speed 

motors. All low voltage wiring instructions, cautions, and 

warnings accompanying the air handler remain applicable, 

except for:
Line & Low Voltage Connections

a. The line voltage connections for both air handlers must 

be the same phase and on the same leg of power.

b. When matched with an S3BM or an S3BW series AC 

outdoor unit, both air handler’s 24V transformers must 

be removed from the control circuit by removing and 

discarding the RED wire located on the transformer’s 

secondary. These outdoor units come standard with 24V 

power supply sufficient for powering both air handlers.

c. Low voltage wiring should be connected as shown in 

Figure 10 (page 18)

.

d. Wire all other low voltage thermostat terminals to both 

air handlers as shown in 

Figure 9 (page 18)

.

Humidifier

The unit has an output to power a humidifier when the 

blower is running. This output is rated to 1.0 amp at 

208/240V. Connection is made to the 

HUm

 terminal on 

the motor control board. See 

Figure 6

.

Dehumidification options

The motor control board (

Figure 12 (page 19)

) has a 

DHUm

 connection that allows the system to increase the 

amount of humidity that is removed from the circulating air. 

This is accomplished by reducing the CFM and allowing 

the cooling coil to become colder. This will only occur 

when there is a call for cooling. There are many ways 

that this can be electrically wired.
1. If the room thermostat incorporates a humidity sensor 

and 

DHUm

 output, connect the 

DHUm

 on the thermostat 

to the 

D

 terminal on the motor control board. See 

Figure 

6

.

2. If using a separate humidistat, connect the 

DHUm

 & 

R

terminals on the humidistat to the 

D

 & 

R

 terminals on 

the motor control board of the air handler. In this option, 

the 

DHUm

 output of the humidistat must be set so it is 

only closed when there is a call for dehumidification.

3. If a humidistat is not available, it is an acceptable option 

to connect the 

R

 & 

D 

terminals on the motor control board 

together with a field supplied wire. This option causes 

the blower to run at a reduced CFM for 10 minutes after 

a call for cooling. 

NotE:

 If outdoor unit is a heat pump, 

connect the

 o 

terminal to the 

D

 terminal.

Electronic Air cleaner (EAc)

The unit has an output to power an electronic air cleaner 

when the blower is running. This output is rated to 1.0 
amp at 208/240V. See 

Figure 12 (page 19)

.

StARtUp & ADjUStmENtS

Before You Start the Unit

Prior to start-up, complete the following inspections:

√

  Verify the unit is level and properly located with adequate 

clearances for servicing the unit. See 

Figure 1 (page 

4)

.

√

 Check condensate drain line(s) for proper drainage (if 

applicable).

√

 Verify the surrounding area and top of the unit is free 

from obstructions and debris.

√

 Check all duct connections. Make sure the duct work 

is adequately sealed to prevent air leakage.

√

 Check all coil connections for leaks (if applicable).

√

 Verify that the line voltage power leads are securely 

connected and the unit is properly grounded. Make 

sure all doors are installed before restoring power to 

the unit

DHUM

R

R

DHUM

HUMIDISTAT

MOTOR

CONTROL BOARD

Figure 6. DHUm Wiring configuration