Emerson 1F83C-11PR Wiring: Heat Pump Y-W Jumper, O/B and C Wire

1. Which thermostat this covers

This article follows the 1F83C-11PR Installation and Operating Instructions (White-Rodgers part 37-7478A-EN), for the programmable 80 Series single stage thermostat sold under the Emerson and White-Rodgers names. The brand’s thermostat line now belongs to Copeland, whose submittal sheet R-5847 covers the same model and its non-programmable twin, the 1F83C-11NP. Copeland also makes the Wi-Fi Sensi thermostats; those are wired differently and have their own Sensi wiring article.

The applications table lists two kinds of system, each limited to one stage of heat and one of cool:

• Conventional: gas, oil or electric, millivolt or 24 V, heat only, cool only, or heat and cool.
• Heat pump: air source or geothermal, with no auxiliary heat.

The instructions rate the terminals at 1.0 A each and 1.5 A for all of them combined. Hardwired power is 20 to 30 VAC. If your old thermostat is wired to L1 and L2 with heavy wires, it is line voltage and this model does not fit; see our line voltage thermostat guide.

2. The terminals

The wiring table in the instructions lists seven terminals:

There is no W2, Y2, AUX, E or L terminal. If your old thermostat had wires on any of these, this is the wrong replacement. Our terminal letter index says what each letter usually means.

3. The three settings on the back

The instructions number three settings on the thermostat, and all three must match your system before you mount it:

1. GAS/ELEC switch. Set it to Gas for a gas or oil furnace, and to Elec for a heat pump or an electric furnace.
2. O/B switch. Factory set to O, which the instructions say suits most heat pumps, where the changeover relay is energized in cooling. Move it to B if the heat pump needs the relay energized in heating.
3. RC/RH jumper. The thermostat connects RC and RH internally, so with one transformer no jumper wire is needed. If you have separate RC and RH wires, clip the jumper so the two terminals are isolated.

Not sure whether you have one transformer or two? Our Rh and Rc page shows how to tell from the old thermostat.

4. Common systems as one table

The instructions describe terminal functions rather than drawing each system. This table applies those rules to the systems the thermostat supports. Each cell is the wire from your old thermostat that goes on that terminal.

Two-wire heat only systems are covered in more depth on our 2-wire heat only page.

5. Wiring steps

1. Turn off power at the breaker or fuse box. The instructions ask you to keep it off until installation is complete.
2. Photograph the old wiring and label each wire by the letter of the terminal it came off, not by its colour. Our wire colour guide explains why colours cannot be trusted.
3. Check the old terminals. Wires on W2, Y2, AUX, E or L mean the 1F83C-11PR is not a match (see section 2).
4. Set the GAS/ELEC and O/B switches, and clip the RC/RH jumper only if you have two separate power wires.
5. Connect the wires using the table above. On a heat pump, add the short Y-W jumper wire.
6. Install the batteries. The instructions call for premium AA alkaline batteries when there is no C wire; with C they are a backup.
7. Restore power and run the equipment test in section 7.

If the display stays blank with fresh batteries, the instructions say to remove the batteries for 2 minutes to reset. A blank display on a hardwired install is also a reason to check for 24 V between R and C; our multimeter guide shows the test.

6. Heat pumps: the Y-W jumper

This is the step that most copies of the manual leave buried in a footnote. The wiring table marks both Y and W with a double asterisk and the note reads: “For heat pump systems, add a jumper wire to connect terminals Y and W.” In practice, on a single-stage heat pump:

• The compressor wire (usually from Y on the old thermostat) goes on Y.
• A short piece of thermostat wire links Y to W, so a call for heat also runs the compressor.
• The reversing valve wire goes on O/B, with the switch set to O or B to match the old terminal.
• The GAS/ELEC switch goes to Elec.

The jumper is a rule of this thermostat, not of heat pumps in general. Some other models, such as Honeywell’s T4 Pro and RTH6360, want nothing on W for a heat pump, so follow the manual of the thermostat you are installing. A wire on B needs care too: on Rheem and Ruud heat pumps B is the reversing valve, but on many Trane, American Standard and older Carrier systems it is the common wire. Our B terminal page and Rheem/Ruud B wire page explain how to tell. For backup heat strips you need a different thermostat; see aux heat vs emergency heat.

7. Installer menu and test

Hold the Menu button for 8 seconds to open the installer menu; Next and Back move between items. The items that matter for wiring:

• 30 and 35: heat and cool cycle rates, slow, medium (default) or fast.
• 50: compressor lockout, a 5-minute delay that protects the compressor from short cycling. It is off by default; on a heat pump or air conditioner it is worth turning on.
• 65 and 66: maximum heat and minimum cool set points.
• 83: continuous backlight, which needs a C wire.

Then test each output as the instructions describe. Fan: set the fan switch to On and the blower should start, then Auto and it should stop. Heat: set the system switch to Heat and raise the setting 1° above room temperature; the system should start and the display show Heat On. Cool: set Cool and lower the setting 1° below room temperature. A “Starting Soon” message means the compressor lockout is counting down. The instructions also warn not to run cooling when it is below 50°F outside.

If one output does nothing, our thermostat troubleshooting guide walks through the checks. Comparing basic replacements? The Honeywell RTH2300 is a similar battery-powered single-stage model that also uses a Y-W jumper on heat pumps.

8. Frequently asked questions