Types
-Bi-metal
-Electronic
-Programmable

Extra low voltage stats (bi-metal)
Types:
-Heating
-Cooling + heating
-Multistage
-Heat pump

*Note: The above can have a built in sub base or separate sub base


Function of Thermostats

*Note: Thermostat functions are determined and selected by the installer of the heating and or cooling equipment


Terminology

Range: Diff between min and max operating points.
-Example: operation of 50 to 90ºF

Differential: Difference between cut in and cut out points (2ºF)
-Example: Set point for 74ºF heat. Heat off at 76ºF and heat on at 74ºF.

Interlock or Dead Band: Used on automatic change over thermostats and prevents constant cycling from heating to cooling.
-Example: Heating set point 74ºF, cooling set point 77ºF, differential of 2ºF and a dead band of 3ºF.


Identified Terminals

Anticipation: Is the addition of heat to the sensing element of the thermostat to prevent excessive temperature changes in the conditioned space

Heat Anticipator/ Heat Anticipation
-Adjustable: Set to current rating of control device, relay or electric strip heater
-Series with heat contacts
-Energized during on cycle
-Higher setting reduces anticipator heat longer
-Lower setting increases anticipator heat shorter

*Note: This device fools the t-stat by making it think that the temp of the conditioned space is higher then it actually is (during the on cycle). Thus preventing overshoot caused by plenum cool down

Cooling Anticipator/ Cooling Anticipation
-Fixed setting
-Parallel to cooling contacts
-Energized during off cycle

*Note: This device fools the t-stat by making it think that the temp of the conditioned space is higher then it actually is (during the off cycle). Thus causes the unit to come on slightly sooner to prevent excessive overshoot



Thermostat Installation

Location: With in the conditioned space select a solid wall free of vibration. Air circulation should not be affected by furniture or draperies… Avoid sources of artificial heat or cold. For example door ways, over supply registers, lights, stoves, direct sunlight, computers…

*Note: Locate 5 feet above floor level and near the return air register

Mounting
-Mounted on wall with out the need for an electrical outlet box
-Mounting base mounted securely to the wall
-Equipment with bi-metal/ mercury bulb, make sure its level

Wiring
-Done in accordance to national + local codes
-All connections tight
-Color coding of wire should be done
-Avoid wire splices
-Control cable should be selected as per the number of conductors required