The White Rodgers 1F78H is a 5/2 Day Programmable Thermostat for heating and air conditioning systems. It features digital programming for weekdays and weekends, manual overrides, and compatibility with various 24V HVAC systems including gas, oil, electric heat. Requires common wire and 3 AA batteries. Below are the key specifications, installation, programming, operation, and troubleshooting instructions.
Assemble tools required: flat blade screwdriver, wire cutter/stripper, hand or power drill with 3/16 inch drill bit (if needed), spirit level.
WARNING: Failure to follow and read all instructions carefully before installing or operating this control could cause personal injury and/or property damage.
The 1F78H thermostat includes terminals for RH, RC, G, W, Y, O, B, C; ELEC/GAS switch; clips for Celsius display (W904) and Hydronic system (W905); requires 3 AA batteries.
Terminal Layout: W, C, RH, B, RC, G, O, Y
Figure 1 Description: Thermostat base with mounting holes, terminals labeled, clip for Hydronic System, ELEC GAS switch, clip for Celsius Display.
Electric Heat or Single-Stage Heat Pump Systems: This thermostat is configured from the factory to operate a heat/cool, fossil fuel (gas, oil, etc.), forced air system. It is configured correctly for any system that DOES NOT require the thermostat to energize the fan on a call for heat. If your system is an electric or heat-pump system that REQUIRES the thermostat to turn on the fan on a call for heat, locate the GAS/ELECTRIC switch and switch it to the ELECTRIC position. This will allow the thermostat to energize the fan immediately on a call for heat. If you are unsure if the heating/cooling system requires the thermostat to control the fan, contact a qualified heating and air conditioning service person.
Hydronic (Hot Water or Steam) Heating Systems: This thermostat is set to operate properly with a forced-air heating system. If you have a hydronic heating system (a system that heats with hot water or steam), you must set the thermostat to operate properly with your system. The factory default setting is forced air heat. Clipping jumper W905 on the circuit board will produce a longer heating cycle which is normally for hot water or steam (hydronic) systems. Both settings produce a very accurate temperature control and can be set to your personal preference. As received, the thermostat cycles the system just under 1°F. With W905 clipped, the system cycles at approximately 1.5°F.
Typical System Compatibility Chart
| System Type | Compatible |
|---|---|
| Standard Heat Only Gas or Oil Fired Systems (24 volt)* | Yes |
| Electronic Ignition Heat Only Two Wire Systems (24 volt)* | Yes |
| Electronic Ignition Heat Only Gas or Oil Fired Systems (24 volt)* | Yes |
| Standard Heat/Cool Systems (24 volt)* | Yes |
| Heat/Cool Systems Electric Heat (24 volt)* | Yes |
| Heat Only Electric Heat Systems (24 volt)* | Yes |
| Cool Only Systems (24 volt)* | Yes |
| Heat Pump Systems (No Aux or Emergency Heat)* | No |
| Hot Water Zone Heat Only Systems | No |
| Hot Water Zone Heat Only (Three Wire) Systems | No |
| Line Voltage Heating or Baseboard 110/240 Volt Systems | No |
| Millivolt Systems Floor or Wall Furnaces | No |
| 12 VDC Mobile Home Application | No |
| Multistage Systems | No |
| Systems Exceeding 30VAC, 1.5 Amp | No |
* Requires common wire for 24VAC at the thermostat
Figure 2 Description: Typical wiring diagram for heat only, 4-wire, single transformer systems. Connections to RH, W; note for 2-wire heat only attach to RH and W.
Figure 3 Description: Typical wiring diagram for cool only, 4-wire, single transformer systems. RED jumper wire must be used on single transformer systems.
Figure 4 Description: Typical wiring diagram for heat/cool, 5-wire, single transformer systems. Jumper between RH and RC.
Figure 5 Description: Typical wiring diagram for heat/cool, 6-wire, two-transformer systems.
Figure 6 Description: Typical wiring diagram for heat pump with reversing valve energized in COOL. Jumper wires on O/B and Y.
Figure 7 Description: Typical wiring diagram for heat pump with reversing valve energized in HEAT.
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 service person.
If your system does not have a G terminal connection, skip to Heating System.
CAUTION: To prevent compressor and/or property damage, if the outdoor temperature is below 50°F, DO NOT operate the cooling system.
This thermostat has a time delay between cooling cycles to allow the head pressure in the compressor to stabilize. If the temperature is adjusted to call for cool within 5 minutes of the last cycle the snowflake icon will blink indicating the thermostat is locked out. After 3 to 5 minutes, the compressor will start and the snowflake icon will stop flashing. This helps prevent the compressor from cycling too quickly and is normal operation for the thermostat.
The Thermostat Buttons and Switches:
The Display:
The configuration menu allows you to set certain thermostat operating characteristics to your system or personal requirements.
Press RUN to make sure the thermostat is in the run program mode, then press PRGM and RUN at the same time to enter the configuration menu. The display will show the first item in the configuration menu.
Press HOLD to change to the next menu item or press TIME to go backwards to the previous item in the menu. To exit the menu and return to the program operation, press RUN. If no keys are pressed within fifteen minutes, the thermostat will revert to normal operation.
| Step | Press Button(s) | Displayed (Factory Default) | Comments |
|---|---|---|---|
| 1 | PRGM and RUN | SL (FA) | Select FA or SL (Fast or Slow) heating cycle rate |
| 2 | HOLD* | d-L (ON) | N/A |
| 3 | HOLD* | E (ON) | Select Energy Management Recovery OFF or ON |
| 4 | HOLD* | LOC (OFF) | Select compressor lockout OFF or ON |
| 5 | HOLD* | 0 HI (0) | Select temperature display adjustment higher or lower |
| 6 | HOLD* | (F) | Select temperature display to F or C |
| 7 | HOLD* | OFF | Returns to normal operation |
| - | RUN | - | - |
* Press HOLD to advance to next item or TIME to move backwards to previous item
This section will help you plan your thermostat’s program to meet your needs. For maximum comfort and efficiency, keep the following guidelines in mind when planning your program.
Look at the factory preprogrammed times and temperatures shown below. If this program will suit your needs, simply press the RUN button to begin running the factory preset program.
Set Current Time and Day
Enter Heating Program
Enter Cooling Temperatures
CAUTION: If the outside temperature is below 50°F, disconnect power to the cooling system before programming. Energizing the air conditioner compressor during cold weather may cause personal injury or property damage.
Check your programming
YOUR THERMOSTAT IS NOW COMPLETELY PROGRAMMED AND READY TO AUTOMATICALLY PROVIDE MAXIMUM COMFORT AND EFFICIENCY!
SAMPLE Heating/Cooling Schedule Plan (Factory Program)
| Heating/Cooling Schedule Plan | |||||
|---|---|---|---|---|---|
| WEEKDAY (5 DAY) | Period | Start Time | Temperature | ||
| 1ST | 6:00 AM | 70 F | |||
| 2ND | 8:00 AM | 62 F | |||
| 3RD | 5:00 PM | 70 F | |||
| 4TH | 10:00 PM | 62 F | |||
| WEEKEND (2 DAY) | Period | Start Time | Temperature | ||
| 1ST | 6:00 AM | 70 F | |||
| 2ND | 8:00 AM | 62 F | |||
| 3RD | 5:00 PM | 70 F | |||
| 4TH | 10:00 PM | 62 F | |||
| WEEKDAY (5 DAY) | Period | Start Time | Temperature | ||
| 1ST | 6:00 AM | 78 F | |||
| 2ND | 8:00 AM | 85 F | |||
| 3RD | 5:00 PM | 78 F | |||
| 4TH | 10:00 PM | 82 F | |||
| WEEKEND (2 DAY) | Period | Start Time | Temperature | ||
| 1ST | 6:00 AM | 78 F | |||
| 2ND | 8:00 AM | 85 F | |||
| 3RD | 5:00 PM | 78 F | |||
| 4TH | 10:00 PM | 82 F | |||
Reset Operation: If a voltage spike or static discharge blanks out the display or causes erratic thermostat operation you can reset the thermostat by pressing up, down and TIME at the same time. This also resets the factory defaults. If the thermostat has power, has been reset and still does not function correctly contact your heating/cooling service person or place of purchase.
| Symptom | Possible Cause | Corrective Action |
|---|---|---|
| No Heat/No Cool/No Fan (common problems) | 1. Blown fuse or tripped circuit breaker. 2. Furnace power switch to OFF. 3. 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 | 1. Pilot light not lit. 2. System Switch not set to Heat. 3. Loose connection to thermostat or system. 4. Furnace Lock-Out Condition. Heat may also be intermittent. | Re-light pilot. Set System Switch to Heat and raise temp above room temp. Verify thermostat and system wires are securely attached. Many furnaces have safety devices that shut down when a lock-out condition occurs. If the heat works intermittently contact the furnace manufacturer or local service person for assistance. |
| No Heat (continued) | 5. Heating system requires service or thermostat requires replacement. | Diagnostic: Set System Switch to Heat and raise the setpoint above room temperature. Within a few seconds the thermostat should make a soft click sound. This sound usually indicates the thermostat is operating properly. If the thermostat does not click, try the reset operation listed above. If the thermostat does not click after being reset contact your heating and cooling service person or place of purchase for a replacement. If the thermostat clicks, contact the furnace manufacturer or a service person to verify the heating is operating correctly. |
| No Cool | 1. System Switch not set to Cool. 2. Loose connection to thermostat or system. 3. Cooling system requires service or thermostat requires replacement. | Set System Switch to Cool and lower temp below room temp. Verify thermostat and system wires are securely attached. Same procedure as diagnostic for No Heat condition except set the thermostat to Cool and lower the setpoint below the room temperature. There may be up to a five minute delay before the thermostat clicks in Cooling. |
| Heat, Cool or Fan Runs Constantly. | 1. Possible short in wiring. 2. Possible short in thermostat. 3. Possible short in heat/cool/fan system. 4. Fan Switch set to Fan On. | Check each wire connection to verify they are not shorted or touching together. No bare wire should stick out from under terminal screws. Try resetting the thermostat as described below. If the condition persists the manufacturer of your system or service person can instruct you on how to test the Heat/Cool system for correct operation. If the system operates correctly, replace the thermostat. |
| Furnace Cycles Too Fast or Too Slow (narrow or wide temperature swing) | 1. The location of the thermostat and/or the size of the Heating System may be influencing the cycle rate. | Digital thermostats normally provide precise temperature control and may cycle faster than some older mechanical models. A faster cycle rate means the unit turns on and off more frequently but runs for a shorter time so there is no increase in energy use. If you would like to increase the cycle time, change the cycle rate to “SL” in the configuration menu. It is not possible to shorten the cycle time. If an acceptable cycle rate is not achieved as received or by changing the cycle rate. Contact a local service person for additional suggestions. |
| Cooling Cycles Too Fast or Too Slow (narrow or wide temperature swing) | 1. The location of the thermostat and the size of the Cooling System can influence the cycle rate. | The cycle rate for cooling is fixed and can not be adjusted. Contact a local service person for suggestions. |
| Thermostat Setting and Thermostat Thermometer Disagree | 1. Thermostat thermometer setting requires adjustment. | The thermometer can be adjusted +/- 4 degrees. See Temperature Display Adjustment in the Configuration menu. |
| Thermostat Does Not Follow Program | 1. AM or PM set incorrectly in program. 2. AM or PM set incorrectly on the clock. 3. Voltage spike or static discharge. | Check current clock and program settings including the AM or PM designations for each time period. If a voltage spike or a static discharge occurs use the Reset Operation listed above. |
| Blank Display and/or Keypad Not Responding | 1. Voltage spike or static discharge. 2. Loss of power to thermostat. | If a voltage spike occurs use the Reset Operation listed above. See No Heat/No Cool/No Fan (common problems) above for items to check in the system. |
| Clock Loses or Gains Time | The thermostat will maintain its program in memory even with no power but the clock time will be incorrect when power is restored. | See No Heat/No Cool/No Fan (common problems) above for items to check in the system. |
| Heat or Cool Starts Early | 1. EMR activated. | See Configuration Menu (Item 4). |