Nortek B6BV Series, Installation Instructions Manual

11

humidistat (see 

page  9

). During normal operation, the 

motor will gradually change speeds during start-up, shut 

down, when thermostat inputs change, and when the duct 

static pressure changes (vents closed or opened, filter 

clogging, etc.). The air handler is configured by setting 

the selector switches on the control board.
Selecting Basic Heating Airflow
The fixed speed motor control board (

Figure 12 (page 

19)

) contains a set of dip switches for setting the blower 

speed. Use pins 1 to 4 to set the blower speed for heating 

and pins 5 to 8 to set the speed for cooling. To determine 

the appropriate switch settings for your installation, see 

Table 6 (page 14)

NotE:

 The minimum electric heat airflow setting may be 

set higher, but must never be set lower than the setting 
shown in 

Table 6

.

Selecting Basic Cooling / Heat Pump Airflow

The basic cooling/heat-pump airflow is controlled by setting 

switches 5 - 8 on the thermostat input board (mounted 

on the blower). All airflows for other modes of operation 

(except electric heat) are determined by this basic setting. 

FAN ONLY would deliver 50% of the selected cooling 
airflow. 

Table 6 (page 14)

 lists the basic airflow values 

versus the airflow selector switch settings and ranges of 

basic air flow settings.

•  When  operating  in  the  heat  pump  mode,  a  higher 

basic airflow setting will increase the energy efficiency 

and capacity but will also decrease the supply air 

temperature.

•  For maximum capacity and energy efficiency, select an 

airflow at or near the top of the range for that nominal 

capacity.

•  For maximum dehumidification, select an airflow near the 

middle or bottom of the range for that nominal capacity. 

Additional information on humidity control can be found 

in the Humidistat and Delay Setting sections.

•  For thermostats with a dehumidifier output, use a field 

supplied wire to connect the thermostat’s dehumidifier 
output to the terminal marked 

DHUm

. The thermostat 

should be set so that the 

DHUm

 output should be high 

(positive) when dehumidification is needed. See also 

Dehumidification Options section.

ImpoRtANt!

 If coil icing is observed, the basic cooling/

heat-pump airflow selected may be too low. Verify the 
setting selected is within the range shown in 

Table 6 

(page 14)

 and that the the system is properly charged. 

Please refer to the instructions supplied with the outdoor 

unit. If icing continues to occur, raise the selected airflow 

one or two steps.

UNIt mAINtENANcE

Proper maintenance is most important to achieve the best 

performance from a air handler. Some of the components 
and their locations are shown in 

Figure 7 (page 12)

. If 

any component of the air handler must be replaced, use 

only factory authorized replacement parts specified in the 

Replacement Parts List provided online.

 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 the air handler.

•  When servicing controls, label all wires prior 

to disconnecting. Reconnect wires correctly.

•  Verify proper operation after servicing.

•  These maintenance instructions are primarily intended 

to assist qualified technicians experienced in the proper 

maintenance and operation of this appliance.

•  Always  reinstall  the  doors  on  the  air  handler  after 

servicing or cleaning/changing the filters. Do not operate 

the air handler without all doors and covers in place.

•  Verify that the thermostat is properly installed and is 

not being affected by drafts or heat from lamps or other 

appliances.

•  To  achieve  the  best  performance  and  minimize 

equipment failure, it is recommended that a yearly 

maintenance checkup be performed. At a minimum, 

this check should include the following items:

Air Filter(s)

 WARNING:

Never operate the air handler without a filter in 

place. Dust and lint in the return air can build 

up on internal components, resulting in loss of 

efficiency, equipment damage, and possible fire.

B6BV series air handlers are not supplied with a single air 

filter when shipped from the factory. It is recommended 

that the filter be cleaned or replaced monthly. Newly built 

or recently renovated homes may require more frequent 

changing until the construction dust has minimized. Filter 
sizes shown in 

Table 2

 are available at most local retailers.

Filters designed to remove smaller particles such as 

pollen, may require additional maintenance.

cABINEt SIZE

FILtER SIZE

A

12 

x

 20 

x

 1

B

18 

x

 20 

x

 1

C

20 

x

 20 

x

 1

table 2. Filter Sizes