Bryant 604D--A Two Cooling Fan Speeds Set-up Dehumidification feature used

604D-- -- A

Two Cooling Fan Speeds Set-up (Dehumidification feature used)

IMPORTANT: Dehumidification control must open control circuit on humidity rise above set point.

Use of the dehumidification cooling fan speed requires use of either a 24 VAC dehumidistat or a thermostat which includes control of a 24 VAC dehumidistat connection. In either case, the dehumidification control must open the control circuit on humidity rise above the dehumidification set point. Dehumidification controls are available with the reverse logic; these must not be used.

1.Using Fig. 15, move the two pin DEHUM jumper from the “STD” position to the “DEHUM” position.

2.Remove fan speed tap wire from the “LOW” terminal on the interface fan board (IFB) (See Fig. 15).

3.Determine correct normal cooling fan speed for unit and application. Add the wet coil pressure drop in Table 5 to the system static to determine the correct cooling airflow speed in Table 4 that will deliver the nominal cooling airflow as listed in Table 1 for each size.

NOTE: If accessory electric heat is installed, the dry airflow must meet or exceed the minimum airflow speed specified in Table 2 for the specific size unit. The electric heat fan speed will be the same as the normal cooling fan speed.

4.Remove the vinyl cap off of the desired speed tap wire (Refer to Table 3 for color coding) for the normal cooling fan speed and place desired speed tap wire on “HIGH” on the interface board.

5.Refer to airflow tables (Table 4) to determine allowable speeds for the dehumidification cooling fan speed. In Table 4, speeds that are not allowed for dehumidification cooling are shaded.

6.Remove the vinyl cap off of the desired speed tap wire (Refer to Table 3 for color coding) for the dehumidification cooling fan speed and place desired speed tap wire on the “LOW” connection on the interface board (IFB). Verify that static pressure is in the acceptable range for the speed tap to be used for dehumidification cooling.

7.Use any spare vinyl plugs to cap any unused speed tap wires.

Table 3 – Color Coding for Indoor Fan Motor Leads

Black = High Speed

Orange = Med--High Speed

Red = Med Speed

Pink = Med--Low Speed

Blue = Low Speed

Single Speed Cooling With Higher Electric Heat Speed

This unit can also be configured to operate with single speed cooling and a higher speed for an accessory electric heater.

1.Using Fig. 15, move the two pin DEHUM jumper from the “STD” position to the “DEHUM” position.

2.See Table 2 for minimum airflow for electric heat operation. Add electric heater and filter pressure drop to duct system static pressure to determine total external static pressure.

3.Select speed tap from Table 4 that will achieve required airflow from Table 2.

4.Remove the vinyl cap off of the desired speed tap wire (Refer to Table 3 for color coding).

5.Connect the desired speed tap wire to the “HIGH” terminal on the interface fan board (IFB).

!CAUTION

UNIT OPERATION HAZARD

Failure to follow this caution may result in unit component damage or improper operation.

To use this mode, a speed connection must be made on the “HIGH” terminal that meets or exceeds the minimum airflow found in Table 2.

!WARNING

ELECTRICAL SHOCK HAZARD

Failure to follow this warning could result in personal injury or death.

Disconnect electrical power to the unit and install lockout tag before changing blower speed.

Continuous Fan Operation

When the DEHUM feature is not used, the continuous fan speed will be the same as cooling fan speed. When the DEHUM feature is used, the continuous fan will operate on IFB “LOW” speed when the DH control lead is not energized, or IFB “HIGH” speed when the DH lead is energized (see Fig. 15).

20