7.3.6 Identify factors that cause combustion spillage.

  • air tight homes with combustion appliances are at risk
  • Negative pressure in the house due to kitchen and bathroom exhaust fans and/or central vacuums
  • Mechanical draft created by a device upstream of the combustion zone such as fan assisted draft (forced or induced draft)
  • Blocked or restructured chimney flue
  • Wind conditions
  • Unbalanced HRV or ERV