Inspection of a Gas Furnace. Inspecting your natural gas furnace will detect problems and save you money in the long run. Typically gas furnaces are divided into two categories, high efficiency models and standard efficiency models. The up-draft model is the most popular.
Newer furnaces do not require chimneys as the products of combustion are turned into a vapour and vented to the outside through PVC lines. ABS pipe is no longer permitted to be used for venting and must be up-graded to 636 PVC when changing furnace.
The major energy saving in high efficiency furnaces is by eliminating the heat loss up the chimney, which continues even when furnace is not running. The combined loss through heat loss and products of combustion is substantial.
AFUE rating of furnace is the estimated energy efficiency rating of the furnace based on one year. The high efficiency furnace will actually produce heat at a cooler temperature than conventional furnace due to the fact that more heat is extracted from combustion which is why the need for a chimney is eliminated.
The components of gas fired furnaces which are typically inspected. Gas fired furnaces are comprised of a cabinet, distribution system, heat exchanger, fan and controls and a thermostat. Humidifiers, HRV’s and electronic filters are just some of the accessories you may find installed on a furnace.
Inspection areas of Gas Furnace. Four main areas of furnace inspections are;
1. Take off fan and burner cabinet covers. Always ensure power is off.
2. Check the heat exchanger, either using light and mirror or combination of tests.
3. Start up the furnace so a visual inspection of flame and exhaust system may be performed.
4. Inspect ducts and supply air systems through out the house.
Life Expectancy
Most gas furnaces are expected to last from 20 to 25 years. The heat exchanger is usually guaranteed for 20 years. Failure of heat exchanger usually means replacement of furnace.
Regular service and maintenance can greatly extend the life of your furnace and some furnaces will last over 35 years.