HVAC 101-Heating Fundamentals and Answers for Final Exam Questions & 100% Verified Answers | Latest Update | Already Graded A+

What is an SSU and what does it do? : It is a unit located on the side of the first which receives power (120 volts) before anything located within the furnace itself. It primarily consists of a switch and a fuse, and it is what allows for power to flow to the door switch. Opening the switch on the SSU will cut power to everything within the furnace. What is an OCPD? Describe its function in detail. : An OCPD is an Over-Current Protection Device, and it will protect conductors and equipment against excess heat generated by over-current within the circuit as a result of overloads, short-circuits, or ground faults. What does "FR" mean, and why is it important to the Sequence of Operations? : The abbreviation "FR" stands for Fan Relay, and it is important to the Sequence of Operation because it is allows for the fan to run in order to satisfy the call for heat at the thermostat. What is the inlet gas pressure to Gas Valve? : 7 2 | P a g e What is the outlet gas pressure for the Manifold? : 3.5 What is the IDR? How does it function? : The IDR is the Induced Draft Relay, and this is what will supply the IDM (Induced Draft Motor) with power in 120 volts when its coil is energized by 24 volts during the call for heat at the thermostat when the r and w contacts therein connect. What is the IDM? How does it function? : The Induced Draft Motor, sometimes known as a Combustion Blower, has two primary functions with in a gas furnace. Its first function, which applies to the Sequence of Operation, allows for air to move from the Heat Exchanger and out the Structure Flu Outlet. The second function, which deals in the safety of the system itself, is to act as a safety control for the ignition process; a Pressure Switch will monitor between the inlet pressure of the Heat Exchanger and the Flu Outlet. What is the action of the High Limit Switch? : The High Limit Switch, which is an AUTOMATIC switch, is normally closed but opens for a rise in temperature around 200 degrees Fahrenheit (93.333 degrees Celsius). This switch is a last-line of defense in case of a fire. What is the action of the Auxiliary Limit Switch? 3 | P a g e : The Auxiliary Limit Switch is mounted in the blower compartment and will monitor return air temperatures in case of overheating. This is a MANUAL switch which will require the technician to run diagnostic and see what is tripping the switch. What is the action of the Roll-Out Switch