3iE Energy-Monitoring Thermostat
The Warmup 3iE Energy-Monitoring Thermostat is a programmable touchscreen thermostat for electric floor heating systems. It supports 120V and 240V configurations and can control additional heating systems through relays. The 3iE carries a 3-year warranty. The FAQs below cover installation, wiring, programming, troubleshooting, and more.

Choose a category
Troubleshooting
Browse guides and FAQs for Troubleshooting.
Programming
Browse guides and FAQs for Programming.
Installation
Browse guides and FAQs for Installation.
Wiring
Browse guides and FAQs for Wiring.
Miscellaneous questions
Browse guides and FAQs for Miscellaneous questions.
About
Browse guides and FAQs for About.
Indoor
Browse guides and FAQs for Indoor.
Thermostats
Browse guides and FAQs for Thermostats.
Preparing for your project
Browse guides and FAQs for Preparing for your project.
Programming & Temperature Control
Browse guides and FAQs for Programming & Temperature Control.
Errors & Troubleshooting
Browse guides and FAQs for Errors & Troubleshooting.
Product Documentation
View or download all available product documents.
Questions & Answers
Select a category to filter the available help articles.
1 “ER1 Out” Thermostat Reading on the Display
It indicates that the thermostat is not set up correctly. Click "Read More" for details.
Learn more2 Heater Error: What Does it Mean if my Thermostat Reads “Heater Error” on the Display?
Heater error will occur if the heating system is not properly wired to the thermostat. Please click "Read More" for details.
Learn more3 Is it normal if I hear a clicking noise from my thermostat?
The clicking noises are the relay opening and closing to let the power through to the heating system. While it should be hardly noticeable, it can be reduced by insulating the surrounding of the electrical…
Learn more4 Output Fault Detected on the Display
It is likely to be a wiring or installation issue. Please consult our installation manual for further assistance. Troubleshooting steps will need to be done with a licensed electrician. Please have the electrician call us…
Learn more5 Thermostat Reads Error Message “ER2” on the Display?
The ER2 message will occur if the floor sensor has a short circuit or has a loose connection. Click "read More" for details.
Learn more6 Un-Mounting Your Thermostat
Please click "Read More" for instructions on how to un-mount your thermostat
Learn more7 What does “ER1” on the thermostat display mean?
The ER1 message will also occur if no floor sensor is connected to the thermostat. Have your electrician make sure that the sensor probe wires are securely connected in ports 1 and 2 of the…
Learn more8 What if my thermostat screen is black and won’t turn on?
If your thermostat has no display and will not turn on when power button is pushed, the thermostat could be wired incorrectly. Click here for more details.
Learn more9 Why is my floor heat not working even though there are no error messages on my thermostat?
Discover why your floor heat is not working despite there being no error messages showing on your thermostat. This guide explains common causes of heating issues and troubleshooting tips to restore your system.
Learn more10 Why is my floor temperature reading incorrect?
If your floor temperature reading varies significantly from the actual temperature of the floor, it could indicate an issue with how the sensor probe was installed. Continue reading to learn how to identify and fix…
Learn more11 Why is my Floor Temperature Reading Incorrect?
If your floor temperature reading significantly varies from the actual temperature of the floor, the sensor probe and cold tail lead may be in the same conduit. Putting both in the same conduit can cause…
Learn more12 Why is my thermostat flashing?
Is your thermostat display flashing? We'll be happy to help get you on the right track in this quick post.
Learn more13 What can I do if my old thermostat has stopped working?
Does it appear that your old thermostat has stopped working? Learn more here about what you can do next to get your floors warm again.
Learn more14 Why is my thermostat stuck on the Warmup screen?
Is your thermostat stuck on the Warmup screen? To advance you'll want to confirm a few details found in this useful post.
Learn more15 ER1 on the Thermostat Meaning
The ER1 message will also occur if no floor sensor is connected to the thermostat. Have your electrician make sure that the sensor probe wires are securely connected in ports 1 and 2 of the…
Learn more16 What Does the Control Fault Error Message Mean?
The Control Fault message might occur for several reasons. Please contact your electrician to have them test the resistance of your heating system based on the heating model that was installed in your floor using…
Learn more17 3iE Adjusting the time
If for some reason you need to change the time, do the following. Touch check under “wake.” Now the word “menu” will appear above the check. Touch it to begin. Next, touch the dash next…
Learn more18 3iE Making Temporary Temperature Adjustments
Your 3IE allows the ability to temporarily change the floor temperature setting for a specific period of time. You will first need to “wake” your thermostat by touching the checkmark on the front screen. Notice…
Learn more19 Why can’t I program my thermostat to read air temperature?
If you have set the floor type to any kind of floating floor, a safety feature in the thermostat will not allow you to increase the target temperature any higher than 81 degrees. Click "Read…
Learn more20 How do Warmup thermostats work?
Wondering how Warmup thermostats work? Learn all about how they work by reading more here.
Learn more21 Can I turn my thermostat above 86°F?
You may be able to alter your advanced settings, allowing your floor to heat above 86°F, depending on the finished flooring type you have.
Learn more22 Can I Have Another Thermostat as an Acting Relay?
When you have multiple floor heating systems being powered that require more than 15amps, you can use an additional 3iE as a relay as opposed to purchasing a separate generic relay which Warmup can supply.
Learn more23 Can I swap my 3iE to a 4iE or Tempo?
Yes. The box and mounting requirements are identical for all horizontal Warmup thermostats and the sensor is compatible. If you'd like to swap a 3iE for a 4iE or Tempo thermostat you will need to…
Learn more24 Can I upgrade to the 6iE?
Do you have an old Warmup thermostat that you'd like to upgrade to the 6iE? Learn all you need to know in this post.
Learn more25 Can my sensor probe be extended?
Yes, please click "Read More" for details.
Learn more26 How do turn on my thermostat unit?
To turn on your system once your thermostat has been installed, simply turn on the breaker. The thermostat screen will light up. After setting the basic parameters of the thermostat, select a steady temperature in…
Learn more27 Master/Relay (relay reading ER1)
When setting up a large installation and connecting two or more thermostats as Master and Relays, all devices MUST have a floor sensor hooked up. Click "Read More" for details.
Learn more28 Can you trim the floor sensor?
The floor probe wire can be trimmed. Learn more here.
Learn more29 Mounting the 3iE Energy Monitoring Floor Heating Thermostat
Read this before choosing your gang box. Click "Read More" for important information.
Learn more30 How far away from the thermostat can the relay be mounted?
Are you wondering about the mount location of your relay? Learn more about mounting your relay in this post.
Learn more31 Can multiple relays be used?
Do you have a large project that you'd like to use multiple relays for? Learn more about connecting more than one relay in this post.
Learn more32 Do you have to wire the floor sensor probe that comes with the 3iE thermostat?
That floor probe is an important part of having your floor heating system function properly. Click "Read More" for details.
Learn more33 How to wire the 3iE Energy-Monitoring Floor Heating Thermostat
Learn how to wire your 3iE and probe for both 120V and 240V configurations. Always use a licensed electrican. Click "Read More" for details.
Learn more34 Does the 3iE have a battery backup?
In the event of a power outage, the capacitor will hold the charge for approx 1 hour, after which time the device will require re-programming.
Learn more35 How can I turn my system on or off completely?
Powering off your thermostat is an important function to be familiar with, as it allows you to completely shut down your system when needed. Whether you prefer visual guidance or step-by-step instructions, we have you…
Learn more36 When my screen goes dark, will my floor continue to heat?
Yes! Click "Read More" for details.
Learn more37 Why is my Floor not Reaching Target Temperature?
If your heating system was installed on a concrete slab or over an unheated space and insulation boards were not used, it is possible that the heat loss into the subfloor will cause your floors…
Learn more38 Initial Set up of the 3iE Energy Monitoring Floor Heating Thermostat
Warmup's 3iE is designed to make the initial programming incredibly easy. Click "Read More" where we outline how to do it.
Learn more39 Do Warmup Thermostats Need Wi-Fi? Smart Home and Matter Compatibility
Matter, previously known as Project Connected Home over IP (CHIP), is now compatible with Warmup's new 7iE floor heating thermostat. Click to learn more.
Learn more40 How Do I Identify Which Warmup Thermostat I Have?
Do you have a Warmup Thermostat but are unsure which model you have? Read this post to help identify which model you have installed.
Learn more41 How to Set a Weekly Heating Schedule on Your Warmup Thermostat
Learn how to both set and delete a weekly programming schedule on your Warmup 7iE Smart Thermostat.
Learn more42 How to Test the GFCI and Fix a Ground Fault Error on a Warmup Thermostat
That "Ground Fault" error on your thermostat after several years could indicate your floor heating system had been damaged during installation. Click "Read More" to learn why.
Learn more43 Do Warmup thermostats zone?
If you are looking to heat multiple spaces separately, you will require multiple thermostats. Read more in this post about zoning.
Learn more44 Does every room with floor heat need its own thermostat?
Want to learn more about the thermostat requirements for floor heating? This post explores several factors you should consider.
Learn moreStill need help?
Our support team is here to help you.