Braeburn 4020 Heat Only Hydronic Universal Programmable Thermostat
NEW! Ultra-Slim Design
Key Features
- 7 Day, 5-2 Day or Non-Programmable
- Large Display with Adjustable Backlight
- Minimum Boiler off Time
- Freeze Protection
- High/Low Floor Limits
- Remote Floor/Slab Sensing*
- SmartLimit® Temperature Limits
- Indoor or Outdoor Remote Sensing*
- SpeedSet® Programming Mode
- Hardwire or Battery Powered
- User and Installer Lock Modes
- Adaptive Recovery Mode (ARM™)
- Temporary Override Limits
- Compatible with 3 Wire Hydronic Zone Systems
*Separate remote sensor required.
Product Series & Warranty
PREMIER SERIES
FREE Contractor Branding on Removable Face Plate!
Residential or Commercial Use
5 YEAR LIMITED WARRANTY
Contact Information
Toll-Free (U.S.): 866.268.5599
International: +1.630.844.1968
Website: www.braeburnonline.com
Terminal Designations
The thermostat features the following terminal designations:
- R: Heat Relay
- W: Heating
- V3: Transformer Common
- C: Transformer Power Close
- S1: Remote Sensor (Indoor, Outdoor, or Slab)
- S2: Zone Valve Power Close
The diagram also indicates connections for a Transformer and a Remote Sensor (Indoor, Outdoor, or Slab).
Architectural Specifications
The heat only hydronic thermostat is the Braeburn® model 4020. It measures 4.25" high x 5.12" wide x 1" deep. It is powered by either 24 Volt AC or two "AA" Alkaline batteries (3.0 Volt DC). In case of power failure, the unit retains all user, installer, and program settings. The thermostat is compatible with hot water, steam, or under-floor hydronic heating systems. It also supports 250mv – 750mv millivolt heating only systems and 3-wire hydronic zone systems. Key features include an adjustable bright blue backlight display, separate sub-base, and multi-level keypad lockout. The temperature control range is between 45° and 90° F (7° and 32° C), with an accuracy of +/-1° F (+/- 0.5° C). The operating humidity range is between 5% and 95% relative humidity. The thermostat includes separate installer and user setup modes, permanent non-volatile memory for user settings, Adaptive Recovery Mode (ARM™), remote sensor capability, slab sensor compatibility, freeze protection, and high/low floor limits.
Product Specifications
| Specification | Details |
|---|---|
| Dimensions | 4.25" x 5.12" x 1" |
| Electric Rating | 24 Volt AC (18-30 Volt AC) 2 amp maximum load per terminal 4 amp total maximum load (all terminals) |
| AC Power | 18-30 Volt AC |
| DC Power | 3.0 Volts DC (2 "AA" Alkaline batteries included) |
| Compatibility | Single hydronic heating systems 250mv – 750mv millivolt heating systems |
| Control Range | 45° to 90° F (7° to 32° C) |
| Display Range | 35° to 99° F (1.5° to 37° C) |
| Accuracy | +/-1° F (+/- 0.5° C) |
| Temperature Differential | 0.5°, 1°, or 2° F (0.2°, 0.5°, or 1° C) |
| Storage Temperature | 14° to 140° F (-10° to 60° C) |
| Operating Humidity | 5% to 95% Relative Humidity |
| Terminations | R, W, V3, C, S1, S2 |
Shipping Information
Individual Carton
| Specification | Details |
|---|---|
| Dimensions | 6.13" x 5.13" x 1.75" |
| Weight | 0.95 lbs. |
Master Carton
| Specification | Details |
|---|---|
| Quantity | 6 |
| Dimensions | 11" x 6.63" x 5.75" |
| Cubic Feet | 0.24 |
| Weight | 6.25 lbs. |
Braeburn 4020 Replaces*
- Honeywell® TH6100AF2004
- Tekmar® 518, 519, 561
- Azel® D-502F
- Taco® 568-22
*Verify specific application requirements. All trademarks are the property of their respective owners.
Compatible Accessories
- 2940 Universal J-Box Adapter Wall Plate
- 5970 Universal Thermostat Guard
- 5390 Remote Indoor Sensor
- 5490 Remote Outdoor Sensor
- AFTS40M Floor/Slab Sensor
Company Information
Braeburn Systems LLC
2215 Cornell Avenue • Montgomery, IL 60538
Toll-Free (U.S.): 866.268.5599
International: +1.630.844.1968
©2025 Braeburn Systems LLC. Product Code: 4020-300-03
