The short answer
To reset a White-Rodgers (Emerson) thermostat in a Northern Virginia home, set the system switch to Cool, Heat or Emer, then hold both buttons for about 10 seconds until the screen goes blank. That’s the reset in White-Rodgers’ manual for its 1F89-0211. Its model numbers start with 1F, and other models can work differently, so check the number on yours. And if the temperature setting jumped 10 degrees on its own, don’t reset anything: the batteries are almost dead.
The 10-degree jump means batteries
This one catches people. When the 1F89-0211 has less than two months of battery life left, it shifts the setting 10 degrees on purpose: 10 cooler in Heat, 10 warmer in Cool. You notice a cold house, which is the point. You can set it back with the arrows, but it shifts again within two days until the batteries are changed.
- It takes two AA alkaline batteries. They keep the clock and the screen going through a power outage.
- A battery icon shows at about half life. When the screen says Change with the battery icon, replace them now.
- Replace them every 2 years, and before you leave the house empty for more than 3 months. Other brands’ batteries and low battery signs: thermostat batteries.
- Set the system switch to Off before you swap them.
- A C wire isn’t required if you change the batteries once a year. More on that in the thermostat C wire.
The $67 Heating Check
We check your furnace, heat pump or boiler before winter. Through December 31. See the offer
What the screen is telling you
Swipe to see all columns →
Swipe to see all columns →
| On the screen | What it means |
|---|---|
| Setting blank | The system switch is Off |
| Setting flashing | Compressor lockout: it’s holding the compressor off for up to 5 minutes |
| Flame, steady or flashing | Heat mode, or calling for heat |
| Snowflake, steady or flashing | Cool mode, or calling for cooling |
| AUX | The auxiliary heat stage is running |
| EMER flashing | Emergency heat mode |
| Save | Cool Savings is on |
| Service | A fault in the heating or cooling system, not in the thermostat |
| Change Filter | A reminder counted in blower hours; clear it by pressing both buttons |
Service is the one people miss. White-Rodgers says it points to a diagnostic fault in the heating or cooling system, and “does not indicate a fault in the thermostat”. A new thermostat isn’t the fix; the system needs a look. The Change Filter reminder is set in blower hours, 200 out of the box and adjustable from 25 to 1,975 in the installer menu (system switch Off, hold both buttons about 5 seconds). The meanings of a flashing snowflake and flame are in thermostat flashing snowflake or Wait.
The five-minute click test
White-Rodgers’ manual has a simple test that tells you whether it’s the thermostat or the furnace:
- Set the system switch to Heat and raise the setting higher than the room temperature.
- Listen at the thermostat for up to 5 minutes for a soft click.
- No click: reset the thermostat. Still no click after the reset: the thermostat needs replacing.
- A click, but no heat: the thermostat did its job, and the heating system needs service.
In Cool, the click can take up to 5 minutes if the compressor lockout is on. Don’t test cooling when it’s under 50°F outside.
No heat, no cooling, no fan
When nothing runs at all, White-Rodgers points at power before the thermostat: a blown fuse or a tripped breaker, the furnace’s power switch turned off, or the blower door not seated. If the system runs nonstop instead, it’s the Fan switch set to On, or a short in the wiring, the thermostat or the system. Furnace cycling on and off? See furnace short cycling.
When the furnace is blinking, not the thermostat
White-Rodgers also makes the control boards inside many furnaces. On its 50A55-843 and 50A65-843 boards, the light flashes a count:
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Swipe to see all columns →
| Flashes | What it means | Next step |
|---|---|---|
| 1 | System lockout | furnace lockout |
| 2 | Pressure switch stuck closed | pressure switch |
| 3 | Pressure switch stuck open | pressure switch |
| 4 | Open limit switch | Often airflow: the filter |
| 5 | Open rollout switch | Call: rollout switch |
| 6 | 115-volt power reversed, or not grounded right | Call |
| 7 | Low flame sense signal | Flame sensor cleaned: $95 to $180 |
| Flashing nonstop | Flame sensed with no call for heat | Call |
| On steady | A failure inside the control itself | Control board replaced: $550 to $1,180 |
One flash when the power comes on is normal. Other White-Rodgers boards, like the 50M56, count differently, so read the label on the furnace door before you trust any table. Rollout is the one never to keep resetting: it trips when flame rolls out of the burner area, and a technician should find out why. An igniter or flame sensor replaced runs $240 to $410 here. More on the light itself in furnace blinking light and furnace won’t turn on, and by brand: Trane, Carrier, Goodman and Lennox.
The system we put in first
Built to take a beating. Put in by our crew.
Heat lamps, snow and rain on one outdoor unit: that’s Trane’s own film. We’re a Trane Comfort Specialist, on Trane’s own dealer locator, and when you pick a Trane, our crew puts it in.
Films: Trane’s own.
When it’s a call
Call when the click test clicks and the heat still doesn’t come, when Service stays on the screen, when the board flashes 5 or 6, or when the breaker trips again. When we come out for a thermostat problem, the technician checks the whole system, not just the thermostat: the equipment, the wiring at both ends, the filter and the drain. The diagnostic is a flat $99, the repair is priced in writing before anything starts, and if the problem really is the thermostat, we say so. If the thermostat itself is done, a replacement runs $300 to $640 here, wired and set up for the furnace or heat pump it runs. Our heating check is $67 per system, through December 31: furnace, heat pump or boiler.
Every brand’s codes and warning lights are in one place: error codes and warning lights. Words on the screen instead of icons? See what thermostat messages mean.
Model details are the makers’ own, from the White-Rodgers 1F89-0211 thermostat manual and the 50A55-843 and 50A65-843 board instructions. Last checked November 10, 2026.
Book it
Book a visit online and put what the screen says in the note, or call (703) 997-9757, answered 24/7. Book from goswiftpro.com/cookiesoffer by November 30 and a box of warm cookies comes with the visit. Rated 5.0 stars across 1,138 reviews on Google, Angi, Yelp, the BBB and Facebook, Virginia Class A license 2705192276.
Questions people ask
How do I reset a White-Rodgers or Emerson thermostat?
On the 1F89-0211, set the system switch to Cool, Heat or Emer, then hold both buttons about 10 seconds until the screen goes blank. Other 1F models can differ, so check the model number.
Why did my White-Rodgers thermostat change 10 degrees by itself?
The batteries have less than two months left. It shifts the setting 10 degrees on purpose so you notice. Put in two fresh AA alkalines and set it back.
What batteries does a White-Rodgers thermostat take?
The 1F89-0211 takes two AA alkaline batteries. Change them every 2 years, or once a year if there’s no C wire, and set the system switch to Off first.
What does Service mean on a White-Rodgers thermostat?
White-Rodgers says it means a fault in the heating or cooling system, not in the thermostat. Book a service call; a new thermostat won’t clear it.
