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- Troubleshoot
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Troubleshoot the gas furnace
When troubleshooting, understand you are working with potentially lethal voltages and a highly flammable gas. If you do not have the ability to do these operations safely, do not attempt them.
Beginning the troubleshoot.
First, does the burner come on and stay on? If there is no burner or nothing happening at all, begin the troubleshoot.
When you begin the troubleshoot, start with the simple things.
Is the thermostat calling for heat? System switch in "heat" and thermostat set well above the ambient temperature. Is the power on to the furnace? If you are not sure, and you have a manual fan switch on the thermostat, turn it on. If the fan comes on, there is power to the furnace. If you are a homeowner, the video below may help.
When you begin the troubleshoot, start with the simple things.
Is the thermostat calling for heat? System switch in "heat" and thermostat set well above the ambient temperature. Is the power on to the furnace? If you are not sure, and you have a manual fan switch on the thermostat, turn it on. If the fan comes on, there is power to the furnace. If you are a homeowner, the video below may help.
If you still have a problem, you need to determine if the furnace is an older furnace with a pilot, or uses electronics to ignite the flame.
Check here to determine if it has a pilot.
If it has a pilot, check here
Most furnaces made in the last 25 years have an electronic method of starting and proving flame, so there will be no pilot.
Check here to determine if it has a pilot.
If it has a pilot, check here
Most furnaces made in the last 25 years have an electronic method of starting and proving flame, so there will be no pilot.
If the unit has no pilot, you need next to determine if it is an 80% efficient furnace or a 90% efficient one.
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The furnaces on the left are 80% efficient furnaces. The galvanized pipe coming out the top is the vent pipe.
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