Gas Trade: Unit 30 - Controls: Purpose and operation
CSA Group's 2020 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.
Controls are mechanical, electro-mechanical, or electrical 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 shut-off 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 to or remove from a voltage 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.
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 (120 kW); and
• Review a control system application to ensure that manufacturer and code requirements are met.
The 7th Edition of the Training materials are revised to include the following changes:
• Updated to current standards and codes.
• Updated assignment questions and added chapter numbers.
• Assignment questions now included at the end of each chapter.
• New preface with a listing of standards and codes referenced in each module.