Pros, Join Our TradeMaster Program!
RS321N Premier Digital Non-Programmable Thermostat
  • Universal Control with 2-Heat / 1-Cool Control for Gas / Electric / Heat Pump / Oil equipment
  • Auto Heat/Cool Changeover, or Heating Only or Cooling Only Configuration
  • Intuitive Setup Menu for Easy Configuration of Options
  • Fan Selector for Automatic, Continuous or Recirculation Fan Operation
  • Adjustable Deadband between Heat and Cool Setpoint in Auto Changeover, from 2°F (1°C) and 8°F (4°)
  • Adjustable Fan Purge Timer to Use All Conditioned Air at the End of a Heating or Cooling Call
  • High and Low Setpoint Limits for Heating and Cooling
  • Commercial Lockout Mode with adjustable 0 to 24 Hour Override in 10min Increments
  • Restricted Temperature Adjustment in Commercial Lockout Mode; +/- 3°F (1°C) or +/-5°F (2°C)
  • Resume Button for Cancelling Commercial Override
  • 2 Occupied (Day-Cool & Day-Heat) and 2 Unoccupied (Night-Cool & Night-Heat) Setpoints
  • Adjustable Balance Points for Heat Pump Compressor and Aux Heat Lockout when Used with Outdoor Sensor
  • Selectable Fahrenheit or Celsius Display
  • Lockable Access Cover
  • Two Digital Inputs with LEDs: LED1 (Green - Filter) and LED2 (Yellow - Fault) with or without LCD Icon Indications
  • LED3 (Red - Emergency Heat; HP Operation Only)
  • Setback Input for Use as Occupied/Unoccupied Trigger with Optional Occupancy Sensors (Ceiling and Wall Mount)
  • Advanced Remote Sensor Bus Sensors Allow up to 6 Indoor, plus Outdoor, Aux1, Aux2 and Aux3 (think Supply Air, Return Air, Walk-In Refrigerator or Freezer, etc.)
  • Random Restart on Power Up Staggers Restart of HVAC System After a Power Outage to Minimize Peak In-Rush Current for any Installation
  • Thermostat Family: RS300 Series - NEW
  • Type: Electronic
  • HVAC Equipment: Gas, Electric, Oil, Heat Pump
  • Control: Heat, Fan, Cool, Auto, Off
  • Humidity: No
  • Programmability: n/a
  • Voltage Type: Low
  • Voltage: 24V
  • Battery: No
  • Remote Sensors: Aux, Indoor, Outdoor
  • Color: White
  • Orientation: Vertical

  • 2 Heat / 1 Cool with Auto Changeover, Heat Only or Cool Only Operation - Operates on both 1-Heat / 1-Cool gas/electric furnaces, and 2-Heat / 1-Cool heat pumps.
  • Set-Up Wizard - Launches installation menu to quickly enter the settings for thermostat functions.
  • Adjustable Vibrant Blue Backlight - Makes viewing and setting the temperature easier any time of the day.
  • Worry-Free Memory Retention - Maintains set point and programmed parameters, even during power outages.
  • Circulating Fan - Maintains optimal air circulation between demand cycles for improved comfort with minimal energy use.
  • High and Low Setpoint Limits - Protects the heating and cooling systems by limiting temperature settings.

  • Heat: 2
  • Cool: 1

  • Rated Voltage: 20V to 30VAC, 24VAC nominal
  • Rated A.C. / D.C. Current: 0.05 to 0.75 AC / 0.0 to 0.75 DC Amp continuous, per output, surges to 3 Amps max.
  • Control Range: Heating: 38 to 88°F (6 to 30°C) in 1° steps Cooling: 60 to 108°F (16 to 40°C) in 1° steps
  • Thermostat Sensing Range: 20 to 124°F (0 to 48°C) Control Accuracy: +/-1°F @ 68°F (0.5°C @ 20°C)
  • Minimum Deadband: (between Heat and Cool) 2°F (1°C)
  • Dimensions: 4.5”H x 4”W x 1”D (114mm x 102mm x 26mm)
  • Thermostat LEDs: Red – Emergency Heat, Yellow – Fault, Green – Filter
  • Equipment Terminations: R - 24V switching voltage, G - Fan, Y1-Compressor1, O - Rev. Valve in Cooling, B-Rev. Valve in Heating
  • Power Terminations: 24V - remote power by removing jumper, 24V(c) - power common (from HVAC equipment)
  • Input Terminations: LED1 (Green LED / Filter Icon), LED2 (Yellow LED / Fault Icon)
  • Occupancy Terminations: CLK1 ( + ), CLK2 ( - )
  • Remote Sensor Terminations: RS+V - Power, RS2 - Return, RS1 – Data
Read more
Multi-Stage (Heat/Cool)
2 Heat/1 Cool
User Interface:
Push Button
Auto Changeover
Large Display
Works with Sensor
Fan Control
Temperature Range (F):
38°F - 88°F
Low voltage
Height (Inches):
Width (Inches):
Depth (Inches):
Speak with a real person who will go out of their way to help!
Closed Now: Phone Hours
Monday – Thursday
8am–7:45pm ET
9am–7:45pm ET

This item is compatible with the following Robertshaw model numbers.

Click on any model number to view complete parts list

warning icon  There are no compatible model numbers that match your entry.

Load More

Please note: Many replacement parts have subtle differences between them and can be easily confused. Attempting to install the incorrect part voids the return coverage. If you are not completely sure your order is correct please give us a call at 1-888-757-4774.

Need help finding a replacement part?

Fill out the part request form and someone will get back to you shortly.

Part request form

Product Reviews

Product Q&A

Add-on Item

This item is cost-prohibitive to ship on its own but is available to ship with orders over $200.

Why don't we show the price of this item?

We try to always offer you the lowest prices possible, but some manufacturers require that we only show these low prices once you take further action.

To see the price, simply add the item to your cart or sign in.