Blower motor lubrication: Regular lubrication of the bearings in the blower motor is critical. It gets hot up there, and if you don't lubricate the bearings with a high-temperature lubricant — not 3-in-1 oil — the bearings fail, the fan dies and you're not doing any more burns until the blower is replaced. A new blower motor is around $120. A 4-ounce bottle of Anderol 465 high-temperature lubricant sells for $9.50. Do the math. Lubricate often.
Expanding aggregates/slag making life difficult? Besides being a housekeeping headache inside the furnace chamber, those bits and pieces that go flying out of the baskets can change both your oil content and your gradations.
Maintenance for NCAT furnaces
One of the byproducts of the ignition method is the generation of unburned hydrocarbons or volatiles. These usually take the form of sulfur, which is very corrosive and yellowish in color.
These volatiles can be absorbed by the material used to manufacture the heating element plates. Left unattended, they will eat the heating element wires embedded in the plates. To eliminate this buildup, you must elevate the chamber temperature to 560 degrees C and allow the furnace to sit at that temperature for two hours. Do not hit the start button, as this will cause the blower to pull cooler room air through the chamber and reduce the chamber temperature.
The goal is to have your ignition chamber remain as clean and white as it was when it was new.
If you see a darkening of the insulating material on the back of the door, this usually indicates an air leak around the door. Adjust the door and latch assembly as shown in the owner's manual.
It's also a good habit to occasionally remove the four ceramic tubes that go through the floor of the chamber to the scale/load cell below and examine them for the brownish volatiles. The volatiles can also accumulate on the tubes and drip down over the scale. If there is a buildup of volatiles on the tubes, you can simply place them in the chamber during the weekly 560 degree C burnout of the chamber to remove the volatile buildup.
Left unchecked, the volatiles could eventually overflow the catch pan on top of the scale/load cell and cause it to fail.
Replacing heating elements
Follow the instructions in your owner's manual. Here's a tip to make it easier to install the new element plates. The new plates come with extra-long leads. After you have loosened the clamps holding the leads from the old plate and before you remove the element plate, slide a piece of plastic tubing over the old lead wire from the rear of the furnace. We've found that plastic coffee stirrers or drink straws will work.
Then, after you have removed the old plate and are sliding the new element into place, feed the lead wires through the plastic tubing. It makes it a whole lot easier than poking around through the insulation trying to find the holes. After the element plate has been pushed in as far as it will go, go around to the back of the furnace, slide off the tubes, tighten the clamps — making sure that the element wires are centered in the clamping assembly (if not centered, it's possible that the wire may be contacting the metal cabinet and shorting out — as evidenced by tripping circuit breakers) and cut off the excess wire.