The White Rodgers 1F79 is a non-programmable heat pump thermostat designed for single-stage heat pump systems with or without auxiliary/emergency heat. It features electronic accuracy, large LCD with backlight, selectable °F/°C display, and compressor lockout protection. Below are the key specifications, installation, operation, and troubleshooting instructions.
Assemble tools required: hand or power drill with 3/16 inch drill bit (if needed), flat blade screwdriver, wire cutter/stripper, level.
Operator: Save these instructions for future use! FAILURE TO READ AND FOLLOW ALL INSTRUCTIONS CAREFULLY BEFORE INSTALLING OR OPERATING THIS CONTROL COULD CAUSE PERSONAL INJURY AND/OR PROPERTY DAMAGE.
CAUTION! To prevent electrical shock and/or equipment damage, disconnect electrical power to the system at the main fuse or circuit breaker until installation is complete.
Before removing wires from old thermostat’s switching subbase, label each wire with the terminal designation it was removed from.
A standard heat/cool thermostat consists of three basic parts: the cover (snap-on or hinge type), the base (loosened by captive screws), and the switching subbase (unscrewed from wall or adaptor plate).
Shut off electricity at the main fuse box until installation is complete. Remove the front cover of the old thermostat. With wires still attached, remove wall plate from the wall. If the old thermostat has a wall mounting plate, remove the thermostat and the wall mounting plate as an assembly.
Identify each wire attached to the old thermostat using the labels enclosed with the new thermostat. Disconnect the wires from the old thermostat one at a time. DO NOT LET WIRES FALL BACK INTO THE WALL.
ATTENTION! This product does not contain mercury. However, this product may replace a unit which contains mercury. Do not open mercury cells. If a cell becomes damaged, do not touch any spilled mercury. Wearing non-absorbent gloves, take up the spilled mercury and place into a container which can be sealed. If a cell becomes damaged, the unit should be discarded. Mercury must not be discarded in household trash. When the unit this product is replacing is to be discarded, place in a suitable container. Refer to www.thermostat-recycle.org for location to send product containing mercury.
Your thermostat replaces:
| Description | Supported |
|---|---|
| Heat Pump (No Aux or Emergency Heat) | Yes |
| Heat Pump (with Aux or Emergency Heat) | Yes |
| Standard Heat & Cooling Systems | No |
| Standard Heat Only Systems | No |
| Millivolt Heat Only Systems – Floor or Wall Furnaces | No |
| Standard Central Air Conditioning | No |
| Gas or Oil Heat | No |
| Electric Furnace | No |
| Hydronic (Hot Water) Zone Heat – 2 Wires | No |
| Hydronic (Hot Water) Zone Heat – 3 Wires | No |
CAUTION! To prevent electrical shock and/or equipment damage, disconnect electrical power to the system at the main fuse or circuit breaker until installation is complete.
CAUTION! Failure to follow and read all instructions carefully before installing or operating this control could cause personal injury and/or property damage.
WARNING! Do not use on circuits exceeding specified voltage. Higher voltage will damage control and could cause shock or fire hazard. Do not short out terminals on gas valve or primary control to test. Short or incorrect wiring will damage thermostat and could cause personal injury and/or property damage. Thermostat installation and all components of the system shall conform to Class II circuits per the NEC code.
CAUTION! Take care when securing and routing wires so they do not short to adjacent terminals or rear of thermostat. Personal injury and/or property damage may occur.
CAUTION! To prevent compressor and/or property damage, if the outdoor temperature is below 50°F, DO NOT operate the cooling system.
WARNING! For California Residents: This product contains a chemical known to the state of California to cause cancer and birth defects and other reproductive harm.
Remove the packing material from the thermostat. Gently pull the cover straight off the base. Forcing or prying on the thermostat will cause damage to the unit.
Electric/Gas Jumper (Fan Option) If your emergency or auxiliary system will energize the blower, then jumper W906 on the thermostat base must be cut. If your emergency or auxiliary heat system requires that the thermostat energize the fan circuit, do not cut jumper W906. If you are unsure of your application, contact a qualified service person.
°F or °C Selection The factory default setting for temperature display is Fahrenheit. If you want the temperature in Celsius, clip jumper W904.
Fast or Slow Cycle Selection The factory default setting is fast cycle, which cycles 1st stage at approximately 1.2°F and 2nd stage 0.75°F. If you prefer slow cycle, clip jumper W905. The 1st stage and 2nd stage would be 1.5°F and 1.2°F respectively.
O/B Terminal Switch Selection The O/B switch on this thermostat is factory set to “O” position. This will accommodate the majority of heat pump applications, which require the changeover relay to be energized in COOL. If the thermostat you are replacing or the heat pump being installed with this thermostat requires a “B” terminal, to energize the changeover relay in HEAT, the O/B switch must be moved to the “B” position.
Battery Location This thermostat does not require batteries to operate. The 2 “AAA” alkaline batteries are for the thermostat to remember the configuration menu selections if AC voltage is lost. If the display shows BATT or when AC power is not present, the batteries are low and should be replaced with fresh “AAA” Energizer® alkaline batteries. For best results, replace all batteries with new premium brand alkaline batteries such as Duracell® or Energizer®. To replace the batteries, install the batteries along the top of the base. The batteries must be installed with the positive (+) ends to the right.
Figure 2. Typical wiring diagram for single transformer systems
THERMOSTAT; SYSTEM TRANSFORMER (Class II); L; R; E; 24 VAC; 120 VAC Hot; SYSTEM MONITOR SWITCH; Neutral; G; W2; Changeover Relay*; C; Y; O/B; Compressor Contactor; Aux Relay (Stage 2); Fan Relay; Emergency Relay. See Note ** Jumper required to use a single Aux Heat for both Second Stage Heat and Emergency. NOTE: If safety circuits are in only one of the systems, remove the transformer of the system with NO safety circuits. * Changeover Relay is energized in COOL when O/B switch is in the “O” position. Changeover Relay is energized in HEAT when O/B switch is in the “B” position.
Figure 3. Typical wiring diagram for two transformer systems with NO safety circuits
THERMOSTAT; L; R; E; 24 VAC; 120 VAC Hot; SYSTEM MONITOR SWITCH; Neutral; SYSTEM; G; W2; TRANSFORMER (Class II); Changeover Relay*; C; Y; O/B; Compressor Contactor; Aux Relay (Stage 2); Fan Relay; Emergency Relay; Limit or Safety Switches; HOT; NEUTRAL; 120 VAC; 24 VAC; CUT AND TAPE OFF! See Note ** TWO COMMONS MUST BE JUMPERED TOGETHER! * Changeover Relay is energized in COOL when O/B switch is in the “O” position. Changeover Relay is energized in HEAT when O/B switch is in the “B” position. ** Jumper required to use a single Aux Heat for both Second Stage Heat and Emergency. NOTE: Polarity must be observed. If the HOT side of the second transformer is jumpered to the COMMON side of the first transformer a short will be made. Damage to equipment will occur when power is restored.
Figure 4. Typical wiring diagram for two transformer systems with safety circuits in BOTH systems
L; R; E; SYSTEM MONITOR SWITCH; G; W2; Changeover Relay*; C; Y; O/B; Compressor Contactor; * Changeover Relay is energized in COOL when O/B switch is in the “O” position. Changeover Relay is energized in HEAT when O/B switch is in the “B” position. Aux Relay (Stage 2); Fan Relay; Emergency Relay; TWO COMMONS MUST BE JUMPERED TOGETHER! 24 VAC; 120 VAC HOT; NEUTRAL; THERMOSTAT; SYSTEM; HOT; NEUTRAL; 120 VAC; Limit or Safety Switches; Limit or Safety Switches; Limit or Safety Switches; 24 VAC; Limit or Safety Switches; COMMON; COMMON; Auxiliary Heating Transformer (Class II); 24 VAC; ACCESSORY RELAY N.O. CONTACT The accessory relay scheme is required when safety circuits exist in both systems. NOTE: See Note ** ** Jumper required to use a single Aux Heat for both Second Stage Heat and Emergency Heat Pump Transformer (Class II)
NOTE To prevent static discharge problems, touch side of thermostat to release static build-up before touching any keys. If at any time during testing your system does not operate properly, contact a qualified serviceperson.
If your system does not have a G terminal connection, skip to Heating System.
EMER bypasses the Heat Pump to use the heat source wired to terminal E on the thermostat. EMER is typically used when compressor operation is not desired, or you prefer back-up heat only.
NOTE To prevent static discharge problems, touch side of thermostat to release static build-up before touching any keys. If at any time during testing your system does not operate properly, contact a qualified serviceperson.
| Symptom | Possible Cause | Corrective Action |
|---|---|---|
| No Heat/Cool/Fan | Blown fuse or tripped circuit breaker; Furnace power switch to OFF; Furnace blower compartment door or panel loose or not properly installed. | Replace fuse or reset breaker; Turn switch to ON; Replace door panel in proper position to engage safety interlock or door switch. |
| No Heat | SYSTEM switch not set to HEAT; Loose connection to thermostat or system; Thermostat or heating system requires replacement or service. | Set SYSTEM switch to HEAT and raise temp above room temp; Verify thermostat and system wires are securely attached; Your furnace manufacturer or service person can describe how to test the heating system to verify it is operating correctly. If the heating system is capable of operation and the no heat condition persists, replace the thermostat. |
| No Cool | SYSTEM switch not set to COOL; Loose connection to thermostat or system; Thermostat or cooling system requires replacement or service. | Set SYSTEM switch to COOL and lower temp below room temp; Verify thermostat and system wires are securely attached; Your cooling system manufacturer or service person can describe how to test the cooling system to verify it is operating correctly. If the cooling system is capable of operation and the no cooling condition persists, replace the thermostat. |
| Heat, Cool or Fan Runs Constantly | Possible short in wiring; Possible short in thermostat; Possible short in heat/cool/fan system. | Check each wire connection to the thermostat to verify it is neatly looped under the terminals. No extra wire should stick out from under the terminals. |
| Compressor Lockout (Flashing Snowflake and Flame Icons) | Compressor cycling too quickly. | The thermostat is in lockout mode to prevent compressor damage. Wait 5 minutes for lockout to reset. |
| BATT Display | Low batteries. | Replace with fresh AAA alkaline batteries. |