Maintenance and Operating Instructions
Maintenance and operating instructions will normally be provided for the furnace by the manufacturer. If no instructions are available, try contacting a field representative or writing the company for a duplicate copy of the owner’s manual.
Caution
Always shut off the electrical power supply to the furnace before attempting to service it. This is very important because DEADLY HIGH-VOLTAGE CONDITIONS EXIST. Be sure to open all furnace fused-disconnect switches before servicing.
Furnace Air Filters, Electronic Air Cleaners, and Humidifers The air cleaner is one of the most important parts of an electric forced-air furnace. A clogged one will cause the furnace to run longer and harder to deliver the desired amount of heat. The result will be higher energy use and higher energy bills.
Air filters should be—inspected on a periodic basis. Clean or replace the filters on a monthly basis during the heating season. Do the same every 3 or 4 months the rest of the year. If the system has an electronic air cleaner, periodically inspect and wash the grids. If the system is equipped with a humidifier, inspect and clean it on a periodic basis.
Caution
Steam-generating-type humidifers are line voltage powered. They must be shut off before servicing.
Heating Elements and Heating Control Wiring
Inspect the heating element and heating control wiring to make certain connections are tight and clean. Check for burned or frayed wires. Check for any breaks or cracks in the wire insulation. These can cause shorting and are a potential fire hazard. All terminal block wiring connections should also be tight and clean.
Caution
Do not attempt to service the controls inside the furnace cabinet unless you are a qualified HVAC technician. DEADLY HIGH-VOLTAGE CONDITIONS EXIST, which can result in serious injury or death.
Check the manufacturer’s maintenance and/or troubleshooting manual for instructions on testing the elements to see which ones are drawing current. The method (and equipment) will varying among different furnace manufacturers. For example, General Electric/Trane requires the use of either an ohmmeter or clamp on ammeter.
Check the furnace wiring diagram to make certain the fuses are of the correct type and amperage.
Blowers/Fans
Some blower/fan motors are permanently lubricated and will not require further attention. Others have ports for oiling and require periodic lubrication. See Blowers and Motors in Chapter 11, “Gas Furnaces.”
Periodically check the blower/fan belts (if used) for belt tension and adjust if necessary. If the belts are frayed or in anyway dam- aged, replace them. Brush the blower/fan blades and the entire enclosure area to keep dust from being blown through the ducts into your rooms. Blower/fan maintenance should be done every time you clean or replace the air filter. You should also inspect and clean the room registers at the end of the ducts at this time.
Ducts
Check the ducts for loose connections or damage, and correct as necessary. Seal all duct seams and joints in the ductwork, and seal the connection between the furnace plenum and the ducts. Doing so will increase the amount of air (and heat or cool air) delivered through the ducts to the rooms.
Insulate ductwork in basements and crawl spaces to reduce heat loss and lower your energy use and costs.
Thermostats
A combined heating and cooling system is designed to operate year round without being shut down. The only changeover required are the room thermostat settings and periodic maintenance.
Check the thermostat setting against the actual temperature in a room. The actual temperature can be measured with a thermometer placed in the center of the room. You may find that the actual room temperature is several degrees lower than the thermo- stat setting. This is a common characteristic of electric heating systems. You will probably have to set the thermostat a bit higher to get the desired results. Just do a little experimenting. On the other hand, the thermostat may be allowing the room temperature to rise above the setting. This may indicate a faulty thermostat. If you suspect a faulty thermostat, have it serviced by an HVAC technician.
Periodically check the batteries in a programmable thermostat. Your heating/cooling problem may be nothing more than an inex- pensive battery replacement. Lower the setting on a programmable thermostat when you are sleeping, away at work, or on a vacation. This will result in lower energy costs.