Emerson 1F83-277 Troubleshooting, Automatic System Changeover, Second Stage Time Delay

OPERATION

The system "mode" is selected by pressing the SYSTEM button. Icons on the bottom right corner of the display will indicate the mode: COOL (), AUTO (), HEAT (), EMER, or OFF. In any mode except OFF, the setpoint temperature will be shown on the right side of the display. In OFF, this area will be blank. The current temperature will be displayed on the left side of the display.

To operate properly in the AUTO mode, the heat setpoint temperature cannot be the same as or higher than the cool setpoint temperature. The heat setpoint must be at least 1° lower than the cool setpoint.

Automatic System Changeover

When the thermostat is in the AUTO mode, both the Flame and Snowflake icons are displayed. The thermostat will call for heat or cool depending on the room temperature. The setpoint temperature displayed will be that of the last mode called. If the last system cycle was heat, the HEAT setpoint will be displayed. If the room temperature raises above the HEAT setpoint and the COOL setpoint and a call for cool is required, the temperature displayed will change to be the COOL setpoint.

Second Stage Time Delay

Your thermostat is designed to determine the optimum time to activate the second stage. Simply raising the temperature in heating or lowering it in cooling will not always force the thermostat to bring the second stage on quickly. There is a time delay from 0-30 minutes depending on the performance of the first stage of the system.

EXAMPLE: For the last 2 hours the thermostat is set on 70° and

the room temperature is 70° with the equipment using only the first stage of heat. Since the equipment is keeping the tempera- ture within 1° of setpoint, the thermostat will delay second stage for a longer time if you manually raise the temperature or if the room temperature quickly changes. Once the second stage comes on, it will come on sooner the next time there is a difference between the setpoint and the room temperature. The net effect of the staging program is that when the first stage is capable of making temperature the second stage will delay longer. When the thermostat calculates that first stage cannot make temperature in a reasonable time, the second stage will come on sooner. This built in function automatically optimizes the use of additional stages of heat or cool.

LOW BATTERY INDICATOR

If the 2 “AA” alkaline batteries are low and should be replaced, the display will be blank except for “LO BATT”. We recom- mend replacing batteries every 2 years. If the home is going to be unoccupied for an extended period (over 3 months), the batteries should be replaced before leaving. When the batteries are low, pressing any button will cause the display to operated for ten seconds. After ten seconds, the display will be blank except for “LO BATT”. You cannot program with low batteries, but you can override setpoint temperature. After “LO BATT” has been displayed for 4 weeks, the thermostat will raise the temperature 10 degrees above your setpoint in COOL mode and will drop the temperature 10 degrees below your setpoint in HEAT mode. If the “LO BATT” condition continues, and when it reaches certain value, the thermostat will turn off all the loads and “LO BATT” will flash.

TROUBLESHOOTING

Reset Operation

If a voltage spike or static discharge blanks out the display or causes erratic thermostat operation, you can reset the thermo- stat by removing the wires from terminals R and C and removing batteries for 2 minutes. After resetting the thermostat, replace the wires and batteries. If the thermostat 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	1. Blown fuse or tripped circuit breaker.	Replace fuse or reset breaker.
(common problems)	2. Furnace power switch to OFF.	Turn switch to ON.
	3. Furnace blower compartment door or	Replace door panel in proper position to engage
	panel loose or not properly installed.	safety interlock or door switch.
No Heat	1. Pilot light not lit.	Re-light pilot.
	2. SYSTEM button not set to HEAT.	Press SYSTEM button to HEAT and raise setpoint
		above room temperature.
	3. Loose connection to thermostat or	Verify thermostat and system wires are securely
	system.	attached.
	4. Furnace Lock-Out Condition. Heat	Many furnaces have safety devices that shut down
	may also be intermittent.	when a lock-out condition occurs. If the heat works
		intermittently contact the furnace manufacturer or
		local service person for assistance.