Things to Look for When Buying a Used Furnace

If you are looking at purchasing a used furnace, inspecting the furnace before purchase is a MUST. The following article will provide you with the information needed to inspect the used furnace.

Items Needed

• Flashlight/ Headlamp
• Angle Grinder with a Wire Wheel
• Wire Brush
• Goggles
• Gloves
• Putty Knife or Scraper
• Piece of Cardboard to lay on
• Wrenches to remove drain valve and bung from the water jacket
• If sludge is present: a plastic spoon

Below we have listed the models of furnaces and a few areas to inspect for corrosion. Corrosion can appear as pits and/or thin areas in the steel. A properly-operated furnace will have very little, if any, evidence of corrosion. 

Classic Models/Forge

• Inspect these areas for corrosion: front firebox corners, long ripple baffle, side walls, under the back chimney area and door frame.
• Inspect the condition of the front door by removing the louvered cover and door heat shields (if installed). Inspect the condition of the chimney and chimney tee, and check for excess creosote below the chimney tee and bezel.

E-Classic/Edge models

• Inspect for corrosion at the front firebox corners, primary air intake, side walls and door frame.
• Inspect the door seal combustion fan, primary air channels, charge tube and refractory. Inspect the condition of the chimney and chimney tee, and check for excess creosote below the chimney tee and bezel.

Maxim models

• Inspect the burn chamber, aerator and burner auger for wear.
• Inspect the chimney box, chimney and hopper. Test augers, fan and ignition for operation.

Water Jacket - All Models: The drain valve and reducing bushing can be removed to inspect the bottom of the water jacket for sludge. Corrosion in the water jacket of the furnace can cause sludge to accumulate at the bottom of the water jacket. This corrosion and sludge accumulation does not occur when furnace water is maintained as recommended in the Owner's Manual. Most furnaces with sludge deposits are likely not economically feasible to repair if leaking.