THE JIM BROWN COMPANY 870-425-5775
Our Family Serving Yours Since 1964
FURNACE QUESTIONS What does AFUE mean? AFUE is the Annual Fuel Utilization Estimate or 'miles per gallon' if you will. The higher this number the less fuel is consumed to produce a BTU of heat. For example, a furnace with an AFUE of 80 sends 80% of the heat from the fuel burned into the conditioned space and 20% of the fuel burned up the chimney to allow the furnace to vent properly. A furnace with an AFUE of 95 will send 95% of the heat from the fuel burned into the conditioned space and 5% will be used to make the furnace vent properly. The way the furnace is built will determine its AFUE.
Why does my gas furnace produce water out the drain in the winter time? A furnace that is high efficiency above 80 AFUE is called a condensing furnace. This furnace is so efficient that it will condense water from the gas it burns, either LP gas or Natural, and this byproduct is the water residual from the gas. Only high efficiency furnaces will condense moisture. These high efficiency furnaces are called condensing gas furnaces. Why does my furnace have a PVC pipe running to the outdoors? A condensing gas furnace removes so much heat from the gas the temperature of the byproducts of combustion that are vented are cool enough to meet the rigid standards of the gas code to use PVC pipe. Since these furnaces condense moisture the PVC is a good choice to keep corrosion from occurring in the flue pipe. When my furnace burner is on there is a motor running before the indoor blower motor starts. What is it for? The furnaces that have been built since 1980 are all higher efficiency furnaces and need some assist to make the flue draft. This motor on all of these furnaces are draft assist induced draft motors. Why does the indoor blower run and put cooler air in the conditioned space at the end of each heat cycle? A gas furnace has a heat exchanger that allows the heat from the flame to transfer heat from the fire to the air that heats the house. When the heating cycle ends and the burner shuts off this heat exchanger still is hot and needs to have that heat transferred to the conditioned space for two reasons. First, energy has been used to make the heat exchanger hot and it is good economy to put that heat in the conditioned space and second it is hard on the heat exchanger and will shorten its life if it is allowed to cool down on its own, the air from the furnace fan will remove this heat evenly and efficiently allowing the heat exchanger to last many times longer. If the power goes out will my gas furnace run? No, it requires electricity to make the fan and other electrical controls that are required to make the unit work. Why is a variable speed blower motor important? Many of the gas furnaces have two stage gas valves this will allow the air temperature to be consistent with each stage and operate at the lowest possible energy cost to run the motor. Does my gas furnace have a pilot light? If it was manufactured prior to 1980 it may have, if it was manufactured after 1980 it most likely will not. My gas furnace does not come on when I adjust the thermostat to call for heat. What can I do? First thing to check is to look at the thermostat to see if the system is turned to heat. Even if the thermostat is set for the heat to come on there is a system selection switch that moves from heat to off to cool. That must be set to heat. If the furnace still does not run it can be reset by resetting the circuit breaker. Is there any maintenance on a gas furnace? Yes, gas furnaces need to be cleaned and adjusted annually. The blower wheel must be clean to be efficient and quiet and the gas pressure needs to be checked to insure proper performance and the most economical operation Why do my windows sweat in the winter time? The reason for this is the temperature difference between the inside air and the window. Just as a glass of ice tea sweats in the summer time your windows will do the same thing. In the winter if the indoor air which has a greater ability to hold water touches a cooler surface and the temperature of the air drops, its ability to hold water decreases. If the temperature difference is lower than the dew point of the air inside the conditioned space it will drop its moisture and create sweat on the windows. Heating and air conditioning equipment do not produce sweat on windows, they do however warm the air that comes in contact with the cooler windows and this creates the conditions for sweating windows. The cure for this is to eliminate the temperature difference between the window surface and the indoor air. One of the most efficient ways to do this is to install storm windows, caulk the existing windows and repair any air leaks. Does a programmable thermostat save money for a gas or electric furnace? Yes, it does. Since a furnace is a powerful appliance the amount of set back is not as critical as it is with air conditioning or a heat pump. There are no rules on how much set back is proper. Extremely large temperature swings will be harder to maintain a level of comfort since the conditioned space will lose heat and the objects will retain this cooler temperature until the heat has surrounded them for a period of time. |
