American Services HVAC maintenance and repair service in Missouri knows that an HVAC Draft Inducer is a fan that pulls air through a heat exchanger and sends it to the outside through a venting system. In HVAC heating systems draft inducers are made of either metal or plastic depending on the Annual Fuel Utilization Efficiency (AFUE). The AFUE is the most widely used measure of a boiler or furnace’s heating efficiency. It measures the amount of heat actually delivered to your operation compared to the amount of fuel that is required to be supplied to the heating unit. HVAC heating units which have an AFUE rating of 80-90% will typically have a Draft Inducer made out of metal and heating units with an AFUE rating of over 90% will typically have a Draft Inducer made out of plastic.
The inducer creates a draft through the heating unit by way of a motor that is powered from the control board. During a normal call for heat, the control board will supply power to the inducer. It is connected to a pressure switch by a rubber hose. As the inducer starts, the pressure switch is closed by the suction of the fan
There are several key failures with Draft Inducers that can occur. If the motor starts when required but the heating unit does not continue with the ignition sequence, most often it problem is a blocked vent pipe or condensate in the inducer assembly. Condensate can also back up into the inducer assembly on systems with AFUE of 90% or higher when the condensate trap becomes clogged. Another common problem is a hot running motor. This most often requires motor replacement.