About Your Furnace, Circulating Air Blower, Thermostat

2.Drop three ice cubes into a glass of water and stir. If, within three minutes, moisture does not form on the glass, the air is too dry and a humidifier would be beneficial. (Do not per- form this test in the kitchen, cooking vapors may produce inaccurate results.)

A good relative humidity is one just high enough to barely start condensation along the lower edges or lower corners of the windows, when it is cold outside. More than that can be damaging.

If the humidity is too high, try these suggestions to lower the humidity:

1.Reduce setting or discontinue use of humidifier.

2.Use range and bathroom exhaust fans while cooking and bathing. Open a door or window for a few minutes to bring in cool drier air.

3.Cook with pans covered.

4.Take shorter baths or showers with cooler water.

5.Install a fresh air intake duct. Cold, dry air brought in from outside to the furnace area lowers the indoor humidity level.

6.Have appliances checked. A malfunctioning appliance can contribute water vapor to the structure.

7.If the problem continues, consult a heating contractor about adding a heat recovery ventilator or air-to-air heat ex- changer.

About Your Furnace

Fig. 2 shows the location of the components in the furnace.

Circulating Air Blower

The blower circulates room air through the furnace, air ducts, and into the rooms of the structure. The blower can be set at the thermostat for automatic or manual operation. In manual mode the blower operates continuously. In automatic, the blower does not come on until a preset time after the gas valve is energized. When the structure reaches the temperature set on the thermostat, the

furnace will shut off. The blower will continue to run until the furnace cools down.

Thermostat

There are many types and styles of thermostats. Most thermostats control both heating and cooling functions and have a Fan Switch with AUTO and ON settings. On AUTO, the Circulating Air Blower will cycle on/off with the furnace on the heating speed unless a call for cooling is initiated. Blower speed will correspond to the mode of operation of the furnace. If the Fan Switch is positioned to ON the blower will run continuously.

In addition some thermostats are programmable with multiple set backs. The set backs can be pre-programmed to lower or raise the temperature automatically.

Be sure to become familiar with your thermostat.

Rating Plate

The rating plate contains important information for the service technician and lists the complete model, manufacturing and serial numbers. You should always provide all these numbers when requesting parts or if you need service. See Fig. 2 for rating plate location.

Door Interlock Switch

All the electrical power for the furnace goes through the door interlock switch. The interlock switch interrupts electrical power to the furnace when the blower door is removed. The furnace will not operate until the blower door is reinstalled.