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Publications GAS TRADE: UNIT 30 (5th ed. pub. 2016)

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GAS TRADE: UNIT 30 (5th ed. pub. 2016) - Controls: Purpose and operation

Publication Year:

  • 2016

Total Pages:



  • CSA
CSA Group's 2015 Gas Trade materials reference the Red Seal Program's trade outlines for your preparation to become a nationally recognized gasfitter. Please visit the Red Seal Program's website for more details.

Unit 30 - Controls: Purpose and operation


Controls are mechanical, electrical, or electro-mechanical components that determine when and how a controlled device will operate or stop operating. A control in its simplest form is a manually operated mechanical device such as a manual shutoff valve. Simple automatic controls can be mechanical, like a pressure relief valve, or electro-mechanical, such as a bi-metal thermostat.

Electrical controls determine when and how power will be delivered to an electrical load. An electrical control, in its simplest form, will apply or remove a voltage to a single load. In more complex control systems, the initial switch of one control will govern the action of another control that may control a load.

Learning Objectives:

At the end of this unit you will be able to:

  • Describe the basic functions of controls.

  • Define common control terms.

  • List the function and selection criteria for mechanical controls.

  • List the function and selection criteria for electrical controls.

  • Describe the interaction of mechanical and electrical control devices.

  • Describe troubleshooting procedures for control systems.

  • State the propane and natural gas code requirements for controls on appliances over 400,000 Btu/h (120kW).

  • Review a control system application to ensure manufacturer and Code requirements are met.

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