Nortek B5BM, Installation Instructions Manual

13

5. Inspect the unit rating plate for the proper type of 

refrigerant and quantity.

6. Weigh in the proper amount of new (or reclaimed) 

refrigerant.

Refrigerant Charging
The system refrigerant charge can be checked and 
adjusted through the service ports provided at the front 
panel of the outdoor unit. Use only gauge lines which have 
a Schrader depression device present to actuate the valve.

Air Circulation
Running the Blower Continuously
Set the thermostat’s system mode to OFF and the 
thermostat’s fan mode to ON. The blower motor should 
run continuously. Check for air delivery at the register(s). 
Ensure that there are no obstructions at the registers or 
in the ducts.

Turning the Blower Off
Set thermostat’s fan mode to AUTO, the blower will shut 
down immediately.

NOTE: If blower is turning opposite of arrow direction, shut 
off main power to the unit and switch any two field wires 
at the disconnect. DO NOT alter unit wiring.

Continuous low speed fan operation
(Standard Blower)
The air handler is equipped with an option of continuous 
low speed fan operation. When G is energized without Y/
Y2, the air handler will operate using the heating speed. 
With  G & Y/Y1 or Y/Y2 energized, the air handler will 
operate in the selected cooling speed (including 40 sec 
blower-off delay).

System Cooling
1. Set the thermostat’s system mode to COOL and fan 

mode to AUTO. Lower the thermostat’s temperature 
mode below room temperature and observe that the 
blower energizes. Check the air being discharged at 
the register is cooler than room temperature. Verify 
unit refrigerant pressures are in order. Blower should 
be turning in direction indicated by arrow.

 NOTE: DO NOT alter unit wiring. Listen for any unusual 

noises. Locate the source and correct as needed.

2. Allow the unit to run for several minutes and then set 

the thermostat’s temperature above room temperature. 
Verify the blower cycles off with the thermostat.

System Heating
1. Set the thermostat’s system mode to HEAT and the fan 

mode to AUTO. Increase the thermostat’s temperature 
above room temperature and observe that the blower 
energizes. Check the air being discharged at the register 
is warmer than room temperature.

2. Allow the unit to run for several minutes and then set 

the thermostat’s temperature below room temperature. 
Verify the blower cycles off with the thermostat.

Minimum Electric Heat Airflow
The minimum electric heat airflow setting controls the 
minimum air flow that will be produced whenever electric 
heater kits are used. When the electric heater kit is 
energized along with a heat pump, the airflow may be 
higher depending on the basic cooling/heat-pump airflow 
setting. The minimum electric heat airflow is selected by 
the red blower wire on 3-speed models.

Blower Configurations
Determining Nominal System Capacity
To select the appropriate airflows for the air handler, the 
nominal system capacity must be known. The nominal 
system capacity is always the nominal capacity of the 
outdoor unit. However, in some situations the nominal 
system capacity may not be the same as the nominal 
capacity of the air handler. Always refer to the outdoor 
unit rating label to determine the nominal system capacity.

NOTE: The CFM values listed in Table 2 (page 17) are 
not dependent on duct static pressure. The VSHE motor 
automatically compensates for changes in duct static 
pressure (within the limits of the motor).

3-Speed Units
The blower speed is preset at the factory for operation 
at the same speed for heating and cooling, by using the 
jumping terminal on the blower motor and connecting it 
to the desired speed with both the red and black wires 
connected to the jumping terminal. NOTE: The control 
board is programmed with a 40 second off delay in the 
cooling mode for optimum system performance and 
efficiency.

 CAUTION:

To avoid personal injury or property damage, 
make sure the motor leads do not come into 
contact with any uninsulated metal components 
of the unit.

For optimum system performance and comfort, it may be 
necessary to change the factory set speed. See Table 2 
(page 17) for airflow data. To change the blower speed:
1. Disconnect all electrical power to the unit and remove 

the upper door.

2. Remove the black and red wires from the blower motor 

jumping terminal. Discard the blower motor jumping 
terminal.

3. Connect the heating speed wire (red) and the cooling 

speed wire (black) to the desired blower speed marked 
on the terminal block of the blower motor.

•  Terminal 4 = Hi speed
•  Terminal 5 = Med speed
•  Terminal 6 = Low speed

4. Replace the upper door and secure it to the unit.
5. Restore power to the unit..