What is a Heat Exchanger and How Does It Work?

Overview

• A heat exchanger is a critical component in an HVAC system responsible for transferring heat.
• It transfers heat between two or more liquids, separated by a wall to prevent mixing.
• It can involve gas and liquid exchanges, useful for heating and cooling.

Common Liquids in Heat Exchangers

• Heating coils: Water, steam, or water-glycol mixture.
• Cooling coils: Chilled water or refrigerant.
• As air is heated, it holds more moisture, which is recovered as condensation on the cooling side.

How Does a Heat Exchanger Work?

• Gas Furnace: Located near the combustion chamber.
• Electric Furnace: Located near the coil.
• Heat source warms the exchanger, heating the air which is then distributed via a blower fan.
• Dual Heat Exchangers:
  • Primary: Often made of aluminized steel for efficient heat transfer.
  • Secondary: Equipped with fins to convert exhaust gases into water.

Why Do Heat Exchangers Crack?

• Metal expands with heat and contracts when cooling, leading to potential cracking over time.
• Cracks can allow combustion gases, including carbon monoxide, to leak into ductwork.
• Causes of overheating:
  • Dirty filters
  • Improper adjustment
  • Worn-out gas valves
  • Improperly sized ductwork
• Life expectancy: 10-20 years; some manufacturers offer lifetime warranties indicating quality.

Identifying a Cracked Heat Exchanger

• Older furnaces may lack sensors to shut down upon detecting carbon monoxide.
• Newer models have sensors to prevent operation if a crack is detected.
• Regular maintenance includes inspecting the heat exchanger.
• Carbon monoxide monitors are recommended in homes.

Services Offered

• Unique Heating & Air Conditioning Inc. serves Northglenn, CO, and surrounding areas.
• They provide HVAC installation, repair, maintenance, and indoor air quality services.
• Technicians can handle major brands like Rheem, Trane, Goodman, Bryant, Amana, Carrier, and Lennox.
• Contact Unique Heating & Air Conditioning Inc. for assistance with heat exchangers or HVAC components.