Title: Assignment: Heating/Air Conditioning Controls Lab (Room 278)
Course: Canvas Practice Course

AC 107 Lab Project - Electrical Control System

The student shall construct an electrical control system based the approved ladder line schematic from the previous assignment.
1. Power to the board shall be switched and fuse protected 115 volts ac via a "pigtail" power cord.
2. A Heating/Cooling thermostat shall be used to provide a call for cooling when the set point is below ambient room temperature and shall energize a circuit which turns "on" a 115 volt ac lamp and fan.  The lamp and fan shall be de-energized when the set point is above the ambient room temperature.  The high-speed winding of the 2-speed blower shall also be energized during a call for cooling.  (NOTE: A SPDT Fan Relay shall be wired into the circuit in such a way that the low speed winding shall be energized during the heating cycle and the high speed shall be energized during the cooling cycle or when the AUTO/ON switch is set to on.
3. A heating/cooling thermostat shall be used to provide a call for heat when the set point is above ambient room temperature and shall energize a circuit which turns "on" a 115 volt heat lamp.  (A standard 75 watt minimum light bulb will suffice.)  The lamp shall be de-energized when the set point is above the ambient room temperature.
4. A normally open Fan Temp Switch shall be mounted so that the temperature sensing element of the switch is close to or touching the heat lamp.  When the switch senses the heat from the lamp, it will close and energize the low speed winding of the blower to move air across the heat lamp.  The circuit shall be such that the fan will remain on after the heat lamp is de-energized until the temp switch opens.
5. The high-speed winding of the 2-speed blower shall be energized when the thermostat "FAN" switch is moved to the "ON" position.   At no time shall both the low and high speed windings be energized simultaneously.
6. All wiring shall be neat, of the correct wire color (see wire color chart below), with properly made connections.
7. All switched loads such as lamps, fans, relay coils, and transformers shall be switched on the hot side of the load.
8. The instructor shall review and approve the completed project.  The student shall  indicate on the schematic the maximum total watts the system will draw (based upon actual measurements taken during operation of the system).

Wire Color Chart

115 volt ac hot | Black
115 volt ac neutral | White
115 volt ac ground | Green
24 volt ac hot | Red
24 volt ac common | Blue
24 volt ac heating | White
24 volt ac cooling | Yellow
24 volt ac fan | Green