Gas Furnace making a Noise? Or not working?

Sputnik Inducer Motor

Noisy Gas Furnace or is it just not working at all?

• Check Inducer Motor
• Check Amperage
• Check Flue Gas Pipe for Blockage
• ​Check Pressure Switch
• Check Blower Motor

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How to Check Furnace Inducer Motor
Apart from the bower motor it is a good idea to check the Inducer Motor. The one to the left is a Goodman / Carrier replacement (Sputnik) motor as it gets it's name from the Soviet Satellite design, It is attached to a metal wheel that takes the exhaust from the heat exchanger and blows it out a flue gas pipe. This motor operates in a high heat area in is susceptible to corrosion, loss of lubrication, dirt, dust, grime which can seize the motor or slow it down to natural wear and tear from the elements.
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​Tools Needed for check: Flashlight,  Amp Meter Power Screwdriver / Drill .

Check Amperage
On the data plate of the furnace find where it says draft motor and read the amperage draw. Using your clamp meter clamp on the wires to the Inducer motor. This is the RLA or Running Load Amps. If the amperage is too high then you have a motor that is struggling or overheating. If amperage is to low then you have a voltage problem to the motor. If the motor is overheating then check the Flue Gas Pipe and Air Pressure Switch in the next steps.

How to check amp draw on inducer motor

How to check flue gas pipe and air pressure switch

Check Flue Gas Pipe for Blockage.
The flue gas pipe takes burnt gasses and air out of the heat exchanger and vents them outside the house. you can disconnect the pipe from the motor or go ontop of the roof and using a flashlight see if there is any leaves, branches, animals or earth materials built up blocking or partially blocking the exit path causing the motor to over heat and shut down causing your furnace not to run. Some furnaces have control boards that will blink a code helping you diagnose the failed component in the furnace.

Check Pressure Switch
​The air pressure switch pictured above checks the negative pressure created by the inducer motor and tells the furnace if it is performing correctly, if not it will shut the furnace down preventing damage and unwanted carbon monoxide gasses into the house. First check the rubber hoses to make sure they are not kinked, torn or have a blockage. If so clean them out or replace them. Next it could be an electrical failure with the switch being stuck open. For an in depth guide check here on how to test a Pressure switch.

Check Blower Motor
Can you hear the blower motor running? is the air blowing out hard or slow? If it is not running then you have another problem and need to call a qualified HVAC technician out to diagnose as these motors have multiple wires, a run capacitor and limit switches that need to be checked for proper operation.  To find an in depth blower check/test post follow the link. If you need a HVAC Repair Service in Las Vegas give us a call or book online.