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Publications GAS TRADE: UNIT 23 (5th ed. pub. 2015)

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GAS TRADE: UNIT 23 (5th ed. pub. 2015) - Forced air add-on devices

Publication Year:

  • 2015

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 23 - Forced air add-on devices


Most add-on devices are optional, but filters are not. A forced-air furnace must never be operated without a filter installed. Without air filtration, dust and lint will build up on the furnace's internal parts, resulting in loss of efficiency, equipment damage, and possible fire.

Add-on devices such as filters, air cleaners, humidifiers, and cooling coils improve the air quality in a building heated by a forced-air furnace.

Filters and air cleaners of various kinds remove particulate matter from the air. Humidifiers increase the relative humidity, increasing comfort for building occupants. Cooling coils allow the forced-air furnace to function as a central air conditioner.

Learning Objectives:

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

  • Select, install, and maintain appropriate air filters and air cleaners.

  • Select, install, and maintain appropriate humidifiers.

  • Inspect and clean an add-on cooling coil.

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GST REG No R119441681
QST REG No R1006017360