How to Reset a Honeywell Thermostat: Verified Steps for Every Common Model

Most Honeywell thermostat problems don’t need a factory reset. If the thermostat lost its connection to the app, you need a WiFi reset. If the display is frozen or acting strangely, you need a restart (a simple power cycle, which erases nothing). If your programmed schedule is a mess, a schedule reset wipes just the schedule and leaves everything else alone. A factory reset is the last resort: it erases your schedule, your WiFi credentials, and your app registration, and you’ll set the thermostat up again from scratch. And no reset of any kind will fix loose wiring, a tripped breaker, or a broken furnace or AC — a reset fixes software problems, not hardware ones.

Below are the exact reset steps for the common Honeywell Home model lines, each one verified against Honeywell’s official support page or the Resideo user manual for that model — linked in every section so you can check my work. This guide was substantially rewritten and re-fact-checked in August 2026.

Key takeaways

• Start with the mildest fix that addresses your symptom: restart for a frozen screen, WiFi reset for connection problems, schedule reset for programming problems. Factory reset last.
• A factory reset erases the schedule, WiFi credentials, HomeKit pairing, and app registration. Plan on 15–30 minutes to reconnect and reprogram afterward.
• Cutting power does not erase your settings — Resideo’s T6 Pro manual confirms the thermostat keeps your settings and router info in memory even with power disconnected. That’s why a restart is always safe to try first.
• The “put the batteries in backward” trick you’ll find all over the internet — including in the old version of this article — does not appear in any Honeywell manual or support page I could find. I’ve dropped it.
• If the screen is blank, the system won’t start, or the breaker keeps tripping, stop resetting. Those are power, wiring, or equipment problems, and the fix is a checklist (below) or an HVAC tech — not a reset.

The four kinds of reset, and what each one erases

Restart (power cycle). Not a true reset at all — you cut power and let the thermostat reboot. Flip the HVAC breaker off for 30 seconds (or pull the batteries on battery-powered models), then restore it. Your settings survive — on basic battery models like the RTH2300 you may only need to re-set the clock and day: Resideo’s T6 Pro manual states the thermostat keeps your settings and home router information in memory even when disconnected from power. This clears most frozen screens and glitches, which is why it’s the first thing to try.

WiFi reset. Clears the stored network credentials (or lets you pick a new network) so you can reconnect. This is the one you need after changing your router, your WiFi password, or your internet provider, or when the app and thermostat stop talking. Your schedule and system settings survive.

Schedule reset. Returns the programmed schedule to Honeywell’s default (typically a Monday–Friday plus Saturday–Sunday pattern, per the T6 Pro manual). WiFi, registration, and system settings survive.

Factory reset. Wipes everything: schedule, WiFi credentials, HomeKit pairing, and the registration that links the thermostat to your Resideo or Total Connect Comfort account. On smart models you will re-add the thermostat to the app as if it were brand new. Use it when you’re moving out, selling the thermostat, or a support agent has walked you through everything else — the T6 Pro manual itself frames clearing your settings as the thing you do before handing the thermostat to someone else, not as routine troubleshooting.

Before you reset anything: the two-minute checklist

A reset can’t fix a thermostat that has no power or an HVAC system that’s faulted out. Before you touch a reset menu, check these — they’re the same first steps Resideo’s own troubleshooting tables start with:

• Blank display? Check the breaker for your furnace or air handler, and the power switch on the furnace itself (it looks like a light switch, usually on or near the unit). On battery-powered models, put in fresh batteries the right way around — and if the display stays dead after a battery change, that’s its own problem with its own fixes.
• “Cool On” or “Heat On” flashing? That’s not a fault. It’s compressor protection — after the compressor shuts off or power is interrupted, the thermostat forces a wait of about 5 minutes before restarting it, to prevent equipment damage (documented in Resideo’s RTH2300/RTH221 guide, and the same behavior exists across the line). Wait it out.
• Heating or cooling runs but performs badly? Weak airflow, warm air from the AC, or short cycling are equipment problems. A reset changes nothing about refrigerant, filters, or wiring.

If the display is on, the system responds, and your problem is software-ish — connection dropped, schedule scrambled, settings hopelessly tangled — carry on.

Find your model, then jump to your steps

The model number is on the back of the thermostat (pull the display gently off its wallplate), on the box, or in the Resideo app under the device’s settings. Then find your line here:

Model line	Resets available	Where the steps are
T5, T5+, T6 (RCHT8610WF, RCHT8612WF, TH6320WF2, TH6220WF2, TH6320WF2003, TH6220WF2006)	Factory, WiFi, schedule, HomeKit	T5, T5+ and T6 section
T9 (RCHT9510WF, RCHT9610WF)	Factory, WiFi (change network), schedule, HomeKit	T9 section
T10 (THX321WF)	Factory, schedule, HomeKit (behind the installer password/date code); WiFi (change network, no password needed)	T10 section
Smart WiFi 9000 touchscreens (RTH9580WF, RTH9585WF, TH9320WF)	Factory, WiFi, schedule	RTH9585WF / Smart WiFi 9000 section
WiFi 7-Day / FocusPro 6000 WiFi (RTH6580WF, TH6320WF1)	Factory, WiFi, schedule — via function codes	RTH6580WF section
VisionPRO 8000 (TH8320WF, RTH8580WF)	Factory, WiFi, schedule — via function codes	VisionPRO 8000 section
VisionPRO TH8321WF	Factory (behind date code), WiFi, schedule	VisionPRO TH8321WF section
RTH2300 / RTH221 non-touchscreen programmables	Schedule restore only (RTH2300); none documented for RTH221	RTH2300 and RTH221 section
Pro 2000 (TH2110DH, TH2210DH)	Schedule restore only (function 40)	Pro 2000 section
CT87 “The Round” dial	None — nothing to reset	CT87 section

Every procedure below comes from Honeywell Home’s official reset page or the Resideo manual linked in that section. If your model isn’t listed — Honeywell has sold a lot of thermostats — that page covers a few more devices, and Honeywell support is at 1-855-733-5465. I have deliberately not guessed at steps for models I couldn’t verify.

T5, T5+ and T6 (RCHT8610WF, RCHT8612WF, TH6320WF2, TH6220WF2)

All four reset types live in one menu. Per Honeywell’s reset page (the T6 Pro user guide documents the schedule, WiFi, and HomeKit options and what each clears):

1. Press and hold Menu on the thermostat.
2. Press the > arrow until you see Reset, and select it.
3. Press > again until you see the reset you want — Factory Reset, WiFi, Schedule, or HomeKit Reset — and select it. Confirm with Yes if asked.

The manual spells out exactly what each option clears: Schedule puts back the default Monday–Friday / Saturday–Sunday program, WiFi clears your router credentials, and HomeKit clears your Apple HomeKit pairing. After a factory reset, set the thermostat up again on-screen or through the Resideo app.

T9 (RCHT9510WF, RCHT9610WF)

The T9 buries its resets under Advanced Setup. Per Honeywell’s reset page:

1. Press the Menu icon on the touchscreen.
2. Scroll down to Advanced Setup and select it.
3. Select Reset, then choose Factory Reset, Schedule Reset, or HomeKit Reset.

For WiFi, the T9 doesn’t have a separate wipe — you switch networks instead: Menu, scroll to WiFi, select Change Network, then pick the new network and enter its password. That handles a new router or a changed password.

T10 (THX321WF)

The T10 is a pro-installed model, so its resets sit behind the installer password — which is just the thermostat’s own date code. Per Honeywell’s reset page:

1. Press the Menu icon.
2. Scroll down to Thermostat Information and write down the Date Code.
3. Press the back arrow, then scroll down to Installer Options.
4. When prompted for a password, enter the date code.
5. Select Reset, then choose Factory Reset, Schedule Reset, or HomeKit.

WiFi works like the T9: Menu, scroll to WiFi, select Change Network, and join the new network. No date code needed for that one.

RTH9585WF and the Smart WiFi 9000 touchscreens (RTH9580WF, TH9320WF)

These color touchscreens keep their resets under Preferences. Per Honeywell’s reset page and the RTH9585WF user guide:

• Factory reset: Press Menu (labeled Settings on some units), select Preferences, press Restore Factory Defaults, then confirm with Yes.
• Schedule reset: Menu, then Preferences, then Restore Default Schedule.
• WiFi reset: Menu, then Wi-Fi Setup. From there you can select Disconnect from Network (confirm with Yes) or join a different network.

One thing to know before you factory reset this line: these thermostats register to Honeywell’s Total Connect Comfort service rather than the Resideo app, and re-registering means entering the thermostat’s MAC ID and MAC CRC codes at mytotalconnectcomfort.com. Those codes are listed on the thermostat’s Register Online screen — the user guide covers the whole process. It’s not hard, but it’s a real 20 minutes, which is another reason to try the WiFi reset first if your actual problem is a dropped connection.

RTH6580WF and FocusPro 6000 WiFi (TH6320WF1)

No touchscreen menus here — this line uses two-number function codes, which look cryptic but take seconds once you know them. Per Honeywell’s reset page:

1. Press and hold the temperature up arrow and the Fan button at the same time until the display changes to two numbers.
2. Use the arrows to set the left number to the function and the right number to the value:
   • Factory reset: left 90, right 1
   • WiFi reset: left 39, right 0
   • Schedule reset: left 85, right 1
3. Press Done.

VisionPRO 8000 (TH8320WF, RTH8580WF)

Function codes again, entered through a hidden box on the touchscreen. Per Honeywell’s reset page:

1. Press System.
2. Press and hold the blank box in the center until the function screen appears.
3. Set the left number and right number:
   • Factory reset: left 0710, right 1
   • WiFi reset: left 0900, right 0
   • Schedule reset: left 0165, right 1
4. Press Done.

The old version of this article listed these same codes with no source; they check out against Honeywell’s current support page, so they stay — now with the receipt attached.

VisionPRO TH8321WF

The TH8321WF looks like the other VisionPRO units but uses a menu-driven reset gated by a date code, like the T10. Per Honeywell’s reset page:

1. Press Menu and go to Dealer Information.
2. Scroll to the bottom and write down the date code, then press Done.
3. Scroll down to Installer Options and enter the date code.
4. Select Reset to Defaults, then Yes.

For a WiFi reset, press Menu, scroll until you see WiFi Setup, and select it. For a schedule reset, press Menu, scroll to Preferences, then select Default Schedule.

RTH2300 and RTH221 non-touchscreen programmables

These basic button-and-LCD programmables have far fewer options, and it’s worth being precise about what actually exists. Per Resideo’s RTH2300/RTH221 setup guide, the RTH2300 has one documented reset — restoring the program schedule to defaults through system setup:

1. Press and hold both the up and down arrow buttons until the display changes (about 5 seconds). You’re now in system setup.
2. Press both arrows together for one second at a time to step through the numbered functions until you reach function 40.
3. Set it to 1 (On) to restore the default program schedule.
4. Press Run to save and exit.

Function 40 exists on the RTH2300 only. For the RTH221, Resideo documents no reset of any kind — if yours is misbehaving, the guide’s troubleshooting list is fresh AAA batteries installed correctly, the circuit breaker, and the system switch settings. If those don’t fix it, you’re looking at replacing an inexpensive basic thermostat, not resetting it.

One more in this family: for the 5-1-1 and 7-day RTH7400/RTH7500 series, Resideo’s manual documents no factory, schedule, or WiFi reset at all — only a filter-reminder timer reset — so if one of those is misbehaving, you’re down to fresh batteries, the breaker, and the troubleshooting table in its manual.

Pro 2000 series (TH2110DH, TH2210DH)

The Pro 2000 series works the same way as the RTH2300, with one difference at the end. Per Resideo’s installer guide for the line:

1. Press and hold the up and down arrows until the display changes.
2. Press both arrows together for one second at a time until you reach function 40.
3. Set it to 1 (On) to restore the default schedule.
4. Press and hold both arrows again to exit and save.

That schedule restore is the only reset Resideo documents for the Pro 2000 — there’s no factory or WiFi reset because there’s no WiFi.

CT87 “The Round” dial thermostat

The classic round dial has no reset because there is nothing to reset — no schedule, no WiFi, no stored settings beyond where the dial is pointing. Resideo’s CT87N/CT87K owner’s manual contains no reset procedure at all; the only controls are the dial and the system/fan switches. If a CT87 stops calling for heat, the problem is wiring, the switch settings, or the heating system itself. One caution: many old round thermostats contain a mercury switch, so if you replace one, don’t toss it in the trash — your local waste authority handles mercury disposal.

About the reversed-batteries trick

Search this topic and you’ll find the same advice repeated everywhere: pull the batteries, put them in backward for ten seconds (or thirty, or a minute — sources disagree, which tells you something), and reinstall them to “factory reset” the thermostat. The old version of this article said it too. I went looking for it in Honeywell’s documentation and came up empty: it’s not on the official reset page and not in any of the manuals linked above. Every documented factory reset is a menu procedure or function code. At best, reversing the batteries is a power cycle with extra steps; at worst you’re pushing current backward through a circuit that wasn’t designed for it. Pull the batteries out for a minute if you want a restart on a battery-powered model — right side up.

When a reset won’t fix it, and when to call a pro

Resets fix corrupted settings and connection problems. They do not fix:

• No power. A blank screen with fresh batteries and a good breaker means a wiring or transformer problem, or a safety switch (like a full condensate pan) cutting power to the thermostat circuit.
• A breaker that trips repeatedly. That’s a short somewhere. Stop resetting the breaker and call an electrician or HVAC tech — repeated resets into a short is how wires overheat.
• Equipment that won’t heat or cool. If the thermostat clicks, the display says Heat On or Cool On, and nothing happens at the furnace or condenser, the thermostat has done its job and the equipment hasn’t. For cooling specifically, run through the not-cooling troubleshooting checklist before assuming the thermostat is at fault.
• Wrong wiring after an install. If the thermostat never worked right from day one, no reset will rearrange the wires. Recheck the wiring against the labels you (hopefully) photographed, or have a pro do it.

My honest rule: resets are free and reversible, so trying one costs you nothing but time — but the second a problem involves the wires behind the wallplate or the equipment in the basement, the thermostat isn’t the patient anymore. A no-cool or no-heat service call is routine work for an HVAC tech, and it’s cheaper than replacing parts by guesswork.

FAQ

Will a factory reset remove my thermostat from the app?

Effectively, yes. A factory reset clears the WiFi credentials and registration, so the thermostat goes dark in the app until you set it up again — through the Resideo app for the T-series, or by re-registering the MAC ID and CRC codes at mytotalconnectcomfort.com for the RTH9585WF-style touchscreens. If you’re moving and leaving the thermostat behind, do this on purpose: Resideo’s manuals recommend clearing schedule, WiFi, and HomeKit so the next owner doesn’t inherit your network credentials.

Does cutting power or pulling the batteries erase my settings?

No. Resideo’s T6 Pro documentation is explicit that settings and router information survive with power disconnected, and the same persistent memory is why factory resets exist as deliberate menu options. Power cycle freely — worst case, on a battery-powered basic model, you re-set the clock.

Which reset do I use when the app says the thermostat is offline?

Start with a restart of your router, then the thermostat’s WiFi reset (or Change Network on the T9/T10). Offline almost always means the WiFi link, not the thermostat’s brain — a factory reset would fix it too, but only the way demolishing a house fixes a squeaky door.

How I put this guide together

I’m a homeowner, not an HVAC technician — and a thermostat reset doesn’t need one. Every procedure above was verified in August 2026 against Honeywell Home’s official reset support page and the Resideo user manuals for each model line, all linked in the sections where they’re used. Procedures I could not confirm from an official source — like the reversed-batteries trick earlier versions of this article recommended for several models — were removed rather than repeated on faith, and for lines with no documented reset (the RTH221 and the RTH7400/RTH7500 series), the manuals were checked directly so I could say so instead of guessing.