Course: HET 119 HVACR Electricity II

Unit 10 Outline

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Unit 10 Outline

1. Operation Controls
  - Thermostats
  - Pressure Switches
  - Flow Switches
  - Humidistats
  - Sequencers
2. Limit and Safety Controls
  - Flame Roll-out Switches
  - Cad-Cell Operation on Oil Burners
  - High Limit Controls
  - Fan Limit Switches
  - Pilot Safety Controls
  - Static Pressure Switches
3. Sequence of Operation
  - Call from the thermostat
  - Combustion Air Switch
  - Ignition Module
  - Pilot/Main Burner Ignition
  - Main Burners
  - Satisfying of the thermostat
4. Troubleshooting Heating Controls
  - Knowing What Should be Happening at any time
  - Using the Volt/Ohm Meter to Troubleshoot
  - Eliminating unnecessary Information and Concentrating on the Task at Hand
  - Replacing the Correct Component

Summary

- Control Devices are the part of an electrical system to operate when, how, where, and what will be turned on, off, and by a variable signal.
- HVAC/R systems need to control the temperature, pressure, flow, humidity, and level for the comfort of humans; thereby, it will be necessary to know all possible sequence of operations of a HVAC/R system.
- Controls can be binary (off and on), analog (variable), or integral (variable and adjusting) controls to give the most efficient control of a HVAC/R system.

Review the vocabulary terms listed below and look up their definitions / descriptions before taking the Vocabulary Quiz.

Vocabulary

- Limit Control
- Operator Control
- Flame Sensor
- Flame Rectification Control
- Air Flow Switch
- Gas Valve
- Thermocouple
- Igniter Control