Rheem RHPL-HM2421JC, Installation Instructions Manual

5.16 AIRFLOW ADJUSTMENT (TRIM) 

Cooling and heat pump airflow can be ad/-10% to suit the installation. To adjust
the airflow, set DIP switches 5 & 6 per Table 8: 

IMPORTANT: The DIP switches are active only when using conventional a 24VAC ther-
mostat.  If  using  the  Comfort  Control

2

System™,  refer  to  Section  5.15  for  adjusting  air-

flows. 

NOTE: Airflow adjustment is active for cooling and heat pump operation only. They are
ignored when electric heat is activated. 

5.17 ELECTRIC HEAT AIRFLOW 

The RHPL-series of air handlers are shipped with the “Low KW airflow” feature turned
OFF. Activate lower airflow feature for lower KW electric heater applications by turning DIP
switch 8 ON.

IMPORTANT: The DIP switches are active only when using a conventional 24VAC ther-
mostat. If using the Comfort Control

2

System™, refer to section 5.8 for low KW heat air-

flow adjustment.

5.18 COOLING MODE DEHUMIDIFICATION 

TABLE 8

AIRFLOW ADJUSTMENT SELECTION TABLE

23

ELECTRIC HEAT AIRFLOW FOR THE RHPN AIR HANDLERS

FIGURE 20

DIP SWITCH SETTING FOR AIRFLOW ADJUSTMENTS

10

Figure X – DIP switch setting for airflow adjustments 

Cooling and heat pump airflow can be ad/-10% to suit the installation.  To adjust the 

airflow, set DIP switches 5 & 6 per Table X.X: 

Airflow Adjustments 

DIP Switch Settings 

2-ton 3-ton 4-ton 5-ton 

Position Switch 

5 

Switch 

6 

Y1 Y2 Y1 Y2 Y1 Y2 Y1 Y2 

A  OFF  OFF  625 775 900 1200 1200 1625 1375 1675 

B ON 

OFF 

700 

850 

1000 1325 1325 1800 1525 

1850 

C  OFF  ON  575 700 800 1075 1075 1475 1250 1500 

D 

ON  ON  625 775 900 1200 1200 1625 1375 1675 

Table X.X – Airflow Adjustment Selection Table. 

IMPORTANT:

  The DIP switches are active only when using conventional a 24VAC 

thermostat.  If using serial communications, refer to section 5 for adjusting airflows. 

NOTE:

  Airflow adjustment is active for cooling and heat pump operation only.  They are 

ignored when electric heat is activated. 

6.7 Electric Heat Airflow

The (-)HPL-series of air handlers are factory programmed to provide adequate airflow for 

electric heat (auxiliary heat).  Airflow for electric heat is fixed and cannot be field adjusted.   

Electric Heat Airflow 

Thermostat 

Input 

2-ton 3-ton 4-ton 5-ton 

W1 or W2 

800 CFM 

1200 CFM 

1600 CFM 

1800 CFM 

6.8 Cooling Mode Dehumidification

CONVENTIONAL THERMOST

A

T WIRING

RHPL-HM2421JC

800 CFM

600 CFM

RHPL-HM3621JC

1200 CFM

600 CFM

RHPL-HM4824JC

1600 CFM

800 CFM

RHPL-HM6024JC

1800 CFM

800 CFM

Air Handler

Model

Above
15KW:

15KW and

below:

RHPL-HM2421

RHPL-HM3621

RHPL-HM4824 RHPL-HM6024

Position

Switch

5

Switch

6

Y1

Y2

Y1

Y2

Y1

Y2

Y1

Y2

A

OFF

OFF

625

775

900

1200

1200

1625

1375

1675

B

ON

OFF

700

850

1000

1325

1325

1800

1525

1850

C

OFF

ON

575

700

800

1075

1075

1475

1250

1500

D

ON

ON

625

775

900

1200

1200

1625

1375

1675

DIP Switch Settings

Airflow Adjustments

10

Figure X – DIP switch setting for airflow adjustments 

Cooling and heat pump airflow can be ad/-10% to suit the installation.  To adjust the 

airflow, set DIP switches 5 & 6 per Table X.X: 

Airflow Adjustments 

DIP Switch Settings 

2-ton 3-ton 4-ton 5-ton 

Position Switch 

5 

Switch 

6 

Y1 Y2 Y1 Y2 Y1 Y2 Y1 Y2 

A  OFF  OFF  625 775 900 1200 1200 1625 1375 1675 

B ON 

OFF 

700 

850 

1000 1325 1325 1800 1525 

1850 

C  OFF  ON  575 700 800 1075 1075 1475 1250 1500 

D 

ON  ON  625 775 900 1200 1200 1625 1375 1675 

Table X.X – Airflow Adjustment Selection Table. 

IMPORTANT:

  The DIP switches are active only when using conventional a 24VAC 

thermostat.  If using serial communications, refer to section 5 for adjusting airflows. 

NOTE:

  Airflow adjustment is active for cooling and heat pump operation only.  They are 

ignored when electric heat is activated. 

6.7 Electric Heat Airflow

The (-)HPL-series of air handlers are factory programmed to provide adequate airflow for 

electric heat (auxiliary heat).  Airflow for electric heat is fixed and cannot be field adjusted.   

Electric Heat Airflow 

Thermostat 

Input 

2-ton 3-ton 4-ton 5-ton 

W1 or W2 

800 CFM 

1200 CFM 

1600 CFM 

1800 CFM 

6.8 Cooling Mode Dehumidification

10

Figure X – DIP switch setting for airflow adjustments 

Cooling and heat pump airflow can be ad/-10% to suit the installation.  To adjust the 

airflow, set DIP switches 5 & 6 per Table X.X: 

Airflow Adjustments 

DIP Switch Settings 

2-ton 3-ton 4-ton 5-ton 

Position Switch 

5 

Switch 

6 

Y1 Y2 Y1 Y2 Y1 Y2 Y1 Y2 

A  OFF  OFF  625 775 900 1200 1200 1625 1375 1675 

B ON 

OFF 

700 

850 

1000 1325 1325 1800 1525 

1850 

C  OFF  ON  575 700 800 1075 1075 1475 1250 1500 

D 

ON  ON  625 775 900 1200 1200 1625 1375 1675 

Table X.X – Airflow Adjustment Selection Table. 

IMPORTANT:

  The DIP switches are active only when using conventional a 24VAC 

thermostat.  If using serial communications, refer to section 5 for adjusting airflows. 

NOTE:

  Airflow adjustment is active for cooling and heat pump operation only.  They are 

ignored when electric heat is activated. 

6.7 Electric Heat Airflow

The (-)HPL-series of air handlers are factory programmed to provide adequate airflow for 

electric heat (auxiliary heat).  Airflow for electric heat is fixed and cannot be field adjusted.   

Electric Heat Airflow 

Thermostat 

Input 

2-ton 3-ton 4-ton 5-ton 

W1 or W2 

800 CFM 

1200 CFM 

1600 CFM 

1800 CFM 

6.8 Cooling Mode Dehumidification

8

8

FIGURE 21

ON DEMAND DEHUMIDIFICATION DIP SWITCH

11

Figure X – On Demand Dehumidification DIP Switch 

The (-)HPL-series air handler is shipped with “On Demand Dehumidification” (ODD) turned 

OFF.  On Demand Dehumidification is used in conjunction with a traditional 24VAC thermostat 

equipped with an on-board humidity sensor.  Activate ODD by turning DIP switch 7 ON.  When 

ODD is turned ON, the thermostat sends a 24VAC signal to the ODD input of the air handler.  

Operation is: 

Normal Humidity (humidity BELOW the thermostat set point): 

Normal Humidity 

Result 

A 24VAC signal is applied to 

the ODD terminal 

Full rated airflow is delivered 

by the blower 

High Humidity (humidity ABOVE the thermostat set point): 

High Humidity 

Result 

No signal applied to the ODD 

terminal 

Airflow is reduced by a preset 

amount to increase latent 

capacity 

The (-)HPL air handler is programmed to provide maximum efficiency and optimum humidity 

removal.  When high humidity is detected, the air handler reduces cooling airflow defined in 

Table X.X. 

Air Handler 

Cooling Airflow 

Reduction 

2-ton 85% 

3-ton 

4-ton 

5-ton 

80% 

Table X.X – ODD Airflow Reduction 

IMPORTANT:

  The DIP switches are active only when using conventional a 24VAC 

thermostat.  If using serial communications, refer to section 5 for adjusting airflows.