Typical Thermostat Operation
Your thermostat is the control center for your Split System. It is very important that the thermostat be located where it can best “sense” the average room temperature. It must not be located where it is exposed to hot or cold drafts or to hot or cold spots on the wall, such as those received from outside walls, walls with pipes inside, or from openings into the attic. Because of the wide variety of programmable thermostats available, we cannot describe how all of them work. However, a typical thermostat has two switches: a SYSTEM switch and a FAN switch.
WARNING
To avoid possible equipment damage, personal injury, fire or death, the following instructions must be observed regarding unit location, air requirements and operating procedures.
The SYSTEM switch can include settings of HEAT, OFF, COOL, AUTO:
HEAT – Your comfort system provides heat when the temperature in the room falls below the temperature selected. No matter how warm the room becomes, cooling will not be pro- vided.
OFF – Your comfort system will not provide heating or cooling, no matter how cold or hot the room becomes.
COOL– Your comfort system provides cooling when the temperature in the room rises above the temperature selected. No matter how cold the room becomes, heat will not be pro- vided.
AUTO– Your comfort system will provide heat when the temperature in the room falls below the temperature selected, and will provide cool- ing when the temperature in the room rises above the temperature selected. With most of these thermostats, you will have a tem- perature range in which neither heating or cooling is being provided. The AUTO set- ting will help your building avoid tempera- ture extremes, but it may increase your operating costs.
Room Temperature |
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Thermostat |
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Temperature |
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| Control Dials |
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| System | Fan | Action |
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| Switch | Switch | |
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| OFF | AUTO | None |
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| COOL | AUTO | System only cools, fan |
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| cycles off and on. | ||
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| COOL | ON | System only cools, fan |
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| runs all the time. | ||
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| HEAT | AUTO | System only heats, fan |
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| cycles off and on. | ||
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| HEAT | ON | System only heats, fan |
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| runs all the time. | ||
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| OFF | ON | No heating or cooling, |
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| Cool/Heat | fan runs all the time. | ||
| Fan Switch |
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| Switch |
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Typical Thermostat
EMERGENCY
HEAT – EMERGENCY HEAT is only used with heat pumps. Emergency heat means the com- pressor (i.e., the outdoor unit) is turned off, and your backup source (if present) will pro- vide heat when the temperatures in the room falls below the temperature selected. (No matter how warm the room becomes, cooling will not be provided.) The backup source is usually electricity, but it may be a gas or oil furnace. The EMERGENCY HEAT setting may be used if you suspect a prob- lem exists with the heat provided by the compressor, but your dealer is not able to service it immediately. With some comfort systems, the EMERGENCY HEAT setting may also be used to provide a quicker
NOTE: Keeping your windows closed whenever the thermostat SYSTEM switch is in the HEAT, COOL or AUTO setting will keep operating costs down.
The Fan switch may include settings of AUTO and ON:
AUTO– The indoor fan is operating when heating or cooling is being provided. NOTE: With some comfort systems, the indoor fan may continue to run for a short time after the compressor shuts off. With most gas fur- naces, the indoor fan will start a short time after the burners are lit, and will keep run- ning for a short time after the burners shut off. When your comfort system is not heat- ing or cooling, the fan will not run.
ON – The indoor fan runs continuously.
