Typical System Compatibility Chart | 1F78 |
Standard Heat Only Two Wire 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) | Yes |
Hot Water Zone Heat Only (Two Wire) Systems | Yes |
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 | Yes |
12 VDC Mobile Home Application | Yes |
Multistage Systems | No |
Systems Exceding 30VAC, 1.5 Amp | No |
Assemble tools required below.
Failure to follow and read 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.
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.white-rodgers.com for location to send product containing mercury.
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.
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 (see fig. 1) 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.
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.
Attach Thermostat Base to Wall
This thermostat requires 2 “AAA” alkaline batteries to operate. If
NOTE To prevent static discharge problems, touch side of the thermo-stat 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.
Fan Operation
If your system does not have a G terminal connection, skip to Heating System.
Cooling 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.
Heating System
Before you begin using your thermostat, you should be familiar with its features and with the display and the location and operation of the thermostat buttons. Your thermostat consists of two parts: the thermostat cover and the base. To remove the cover, gently pull it straight out from the base. To replace the cover, line up the cover with the base and press gently until the cover snaps onto the base.
The Thermostat Buttons and Switches
Now that you are familiar with the thermostat buttons and display, read the following information to learn about the many features of the thermostat.
TEMPERATURE DISPLAY ADJUSTMENT — Your new thermostat has been accurately set in our factory. However, if you wish, you may adjust your new thermostat temperature display to match your old thermostat. This can be accomplished (within a ±3° range) as follows:
DISPLAY BACKLIGHT — (Not available on earlier models.) The display backlight improves display contrast in low lighting conditions. Selecting backlight ON will turn the light on for a short period of time after any button is pressed. Selecting backlight OFF (default) will keep the light off. Turn the display backlight feature ON as follows:
ELECTRICAL DATA
THERMAL DATA
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
Batteries
For best results, replace batteries once a year with new premium brand alkaline batteries such as Duracell® or Energizer®.
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.
5. Heating system requires service or thermostat requires replacement. | Re-light pilot. Set SYSTEM Switch to HEAT and raise setpoint temperature above room temperature. Verify thermostat and system wires are securely attached. Many furnaces have safety devices that shutdown when a lock-out condition occurs. If the heat works intermittently contact the furnace manufacturer or local service person for assistance. 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 below. 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 setpoint temperature below room temperature. 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. |
Symptom | Possible Cause | Corrective Action |
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 above. 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, clip Jumper W-905 as for Hydronic Heating Systems. It is not possible to shorten the cycle time. If an acceptable cycle rate is not achieved as received or by clipping W-905 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 +/- 3 degrees. See Temperature Display Adjustment in the Operation section. |
Blank Display and/or Keypad Not Responding | 1. Voltage spike or static discharge. 2. Battery change required. | Replace batteries and check the heat/cool system for proper operation. If a voltage spike occurs use the Reset Operation listed above. |
White-Rodgers is a division of Emerson Electric Co.
The Emerson logo is a trademark and service mark of Emerson Electric Co.
Homeowner Help Line: 1-800-284-2925
www.white-rodgers.com
www.emersonclimate.com
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