Robertshaw RS4220C, RS4320C User Manual

Thank you for purchasing a Robertshaw RS4000C thermostat. This
user’s manual will guide you through the setup of the RS4220C two
stage, and the RS4320C three stage* thermostats. The thermostat
should already be mounted and correctly wired. The default settings
will enable the thermostat to operate efficiently.

Features

• Pop-Up Wizard

• Automatic changeover

• Circulating Fan

• Worry-Free memory retention

• Easy change battery

• Large back lit display

• Filter change reminder

• Low battery indicator

• Fahrenheit and Celsius displays

• Dual power

• Adjustable 1

st

stage temperature differential: 0.5 °F to 3.0 °F (0.5 °C

to 1.5 °C)

• Accuracy within ±1 °F

• Universal staging on multi-stage units

• Automatic heating shutdown if temperature exceeds 99 °F (37 °C)

• Keypad security lockout

• User settable Hi and Lo temperature limits

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RS4220C
RS4

3

20C

352-00058-001 Rev B

USERS MANUAL

* Three stage heating available for heat pump applications only.

Application

The Robertshaw RS4000C family of thermostats is designed to control
gas, electric, oil, heat pump, and millivolt heating and electric cooling
systems. The RS4220C is a two stage thermostat. The RS4320C can
support three stages of heating and two stages of cooling in heat pump
applications.

The RS4000C thermostats are non-programmable and operate on
separate heating and cooling setpoints.

IMPORTANT SAFETY INFORMATION
WARNING:

• Always turn off power at main fuse or circuit breaker panel before
installing, removing, cleaning, or servicing thermostat.

• Read all the information in this manual before installing
this thermostat.

• This is a 24V AC low-voltage thermostat. Do not install on voltages
higher than 30V AC.

• All wiring must conform to local and national building and electrical
codes and ordinances.

• Do not short (jumper) across terminals on the gas valve or at the
system control to test installation. This will damage the thermostat
and void the warranty.

• Do not connect ground to any terminal in this unit.

• This thermostat is configured with automatic compressor protection
to prevent damage because of short cycling or extended power
outages. Short cycle protection provides a delay between heating
and cooling cycles on heat pumps.

Detailed mounting and wiring instructions are explained in the
Installation Manual.

Refer to the pop up wizard section in the installation manual for a
complete list of factory defaults and contractor settings.

Providing Power to the Thermostat

For wiring diagrams refer to the Installation Manual.
The thermostats will operate using 24V AC or two AA batteries. When

the two AA batteries are installed the thermostat will continue to run if
the 24V AC fails.

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Installing or Changing the Batteries

To remove the battery compartment gently
squeeze the ribbed edges on both sides.

The battery compartment will pull down
from the thermostat body and will detach.
Install two AA batteries following the
polarity as shown inside the compartment.
Place compartment back into the
thermostat.

When the batteries are low the thermostat will enter a low battery mode.
Low battery mode has two levels.

• LEVEL 1: The low battery icon will be displayed.
The thermostat will continue to operate. Replace
the batteries as soon as possible

• LEVEL 2: The low battery icon will flash. If 24V AC is
present the thermostat will continue to operate if
the batteries are discharged or removed. If 24V AC
is not present the thermostat runs on batteries only
and THE SYSTEM WILL NOT OPERATE. Replace
batteries immediately.

Replace batteries if leaving thermostat unattended for more than 30 days.

Display Description

The thermostat display will show information that is being used during
operation or programming. This illustration shows all of the display’s
possibilities with an explanation.

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1

4

2

8

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1. Used with setpoint.

2. Used for current setpoint and some configuration data.

3. HVAC mode and status. Icons blink when active. A is
for Auto, 2 is for second stage, E is for emergency.
Both the 2 and E will be displayed when 3rd stage heat
is active.

4. Indicates when security is active.

5. Low battery indicator.

6. Used for ambient temperature and configuration data
(e.g., first stage differential, F or C, etc.).

7. Fan status (rotates when active).

8. Fan mode selected by pressing FAN button.

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User Settings – Defaults

During any program changes the display returns back to the operating
display if a button has not been pushed in 10 seconds.

The temperature scale is set to Fahrenheit.
Night light is on.
The first stage differential is 1 °F.
The second stage differential (RS4220C) is 2 °F.
The second stage delay is 20 minutes.
Third stage delay (RS4320C) is 20 minutes.
Auto changeover is enabled.
Auto changeover deadband is 3 °F.
Filter reminder length is off.
Temperature offset is 0 degrees.
The HI heat limit is 90 °F (32 °C).
The LO cool limit is 45 °F (7 °C).
The operation mode is OFF.
The fan setting is Auto.
The keypad has no password protection.
Refer to the Pop-Up Wizard section in the installation manual for a

complete list of factory defaults and contractor settings.

Emergency Heat

Your system may include Emergency Heat. The RS4220C and RS4320C
thermostats have an emergency heat capability for multi stage heat
pump systems. To determine if your system is capable of using

emergency heat contact your contractor. Use the button to enter
the EMER mode. An E will be displayed with the Heat symbol. This
mode is used to bypass the heat pump when it needs servicing or when
it cannot keep up with the heat demand.

Auto Changeover

Auto changeover is the ability of the thermostat to switch automatically
between heating settings and cooling settings. This is useful in Spring
and Fall when the days are warm and the nights are cool. In heat mode
if the room continues to warm beyond a set threshold the thermostat
switches to the cool mode and the associated cooling settings. The
reverse is also true.

As the room temperature changes, the thermostat will call for heating or
cooling as needed. To prevent the heating and cooling systems from
overriding each other, an auto changeover deadband is used.

The deadband is the minimum temperature swing before changing from
heating to cooling or vice versa. The larger the deadband the more the
room temperature will vary.

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Operating the Thermostat

Any setting can be changed when it is flashing by pushing or
If a button is not pushed for 10 seconds the thermostat returns to

operation.
The following buttons can be accessed from the front panel.

LIGHT BAR: Turns on the display back light for 10 seconds.
FAN: Turns fan to AUTOMATIC, CIRCULATE or ON.
UP ARROW: Raises the setpoint or increases flashing item.
DOWN ARROW: Lowers the setpoint or decreases flashing item.
HEAT/COOL: Toggles through OFF, HEATING, COOLING, and AUTO. If

configured as HP then emergency heat is also displayed.

Changing the User Settings

When and are pressed at the same time the thermostat will
display the current settings in order.

To change any setting:

When the setting is visible and flashing press the or
arrows to adjust the number on the screen.

SC = Scale in °F (Fahrenheit) or °C (Celsius)

bL = Display backlight always on ”y” or off ”n”. Also called the nightlight

feature. If the thermostat has been wired with 24V AC (R and C
terminals) then this feature will be displayed and the setting can
be changed.

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dF = The differential keeps the thermostat from turning on for small

changes in temperature. When in Fahrenheit the range is 0.5 to 3.0
Degrees. In Celsius the range is 0.5 to 1.5 Degrees. The differential
is factory set at 1.0 °F (0.5 °C). This means that whenever the room
temperature is more than 1 °F (0.5 °C) different from the set
temperature the system will turn on. If the system is turning on too
often, increase the differential setting. Note that a larger differential
will mean the room temperature changes more before the system
turns on.

d2 = Second Stage Differential = Operates with the first stage to control a

second heating/cooling system. This number will be added to the
first stage differential (See: Two Stage Systems). If the first stage is
running too often lower the settings. This will turn the second stage
on to help the first stage. If both stages are coming on too often
then increase this setting to delay the second stage.

dL = Second Stage Delay = This timer starts when the first stage turns

on. It resets when the first stage turns off. If this timer runs out the
second stage will turn on (See Two Stage Systems).

dL E2 = Third Stage Delay = This timer starts when the second stage

turns on. It resets when the second stage turns off. If this timer
runs out the third stage will turn on. Available on RS4320C only.
(See Three Stage Systems).

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Auto changeover enable = Makes the auto changeover mode available.

When chosen, the user can select auto changeover mode which
automatically switches between heating and cooling. Note that
the High and Low setpoint limits are not enforced in auto
changeover mode.

db = Deadband for auto changeover = the number of degrees that the

room temperature can move away from the active setpoint until
heating or cooling is called for. The larger the deadband the more
the room temperature will vary. This can be from heat to cool or
cool to heat. Available only when auto changeover is enabled.

Hi = High Heat Limit = This is the highest allowed heating setpoint.

The user will not be allowed to set a heating setpoint higher than
this value.
Note: High Heat Limit is not enforced in auto changover mode.

Lo = Low Cool Limit = This is the lowest allowed cooling setpoint.

The user will not be allowed to set a cooling setpoint lower than
this value.
Note: Low Cool Limit is not enforced in auto changover mode.

FL = Timer to remind the home owner to maintain the filter. Default

setting is off. The timer runs when the system is on and can be set
at 'n' (OFF) or 'y' (ON). When set to 'y' the filter reminder (FL) will

appear after 1000 hours of system operation. Press the and
buttons to restart the filter timer.

CY = Cycle Timer allows a compressor to rest between cycles. Can be

set from 0 to 5 minutes in 1 min increments.

WARNING: A wrong short cycle setting can
damage your equipment.This should only be
changed by a trained HVAC professional.

CL = Calibration offset. Changes the displayed temperature from the

actual temperature by +3 to -3 degrees in one degree increments.
Increasing the offset by +2 will cause the thermostat to display a
temperature that is 2 degrees higher than the actual room.

Creating a Password – Protect the Settings

The buttons on the front of the thermostat can be locked with a password.
To create a password:

1. Press the and buttons at the same time and hold them in
for 5 seconds.
You will be asked for a 2 digit password.

2. The digits are set using the and buttons to progress
through 00 to 99.

Press the to move to the next digit. Press to move back.

3. The password is saved after 5 seconds.

All of the front buttons are now locked out until the password is entered.
Pressing any button will cause to flash.

To unlock the buttons:

1. Push and hold the and buttons for 5 seconds until the
request for password is displayed.

2. Enter the digits for the password by pressing or to
progress through the numbers to the password.

3. When the correct password is set, wait for 5 seconds to unlock the
system.

4. If the wrong password is entered the display will flash -- for 5
seconds then return to normal.

Once the security has been disabled, a password needs to be
re-created to protect the settings.

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