Gas Furnace Inspection Checklist

furnace repair service

While many homeowners know they need to inspect their furnaces, most don’t know how to do it properly. Do you have a gas furnace? Here is a gas furnace inspection checklist as given by furnace service providers:

Check the igniter using an ohmmeter.

You need to measure the resistance through the igniter. If the furnace has a silicon nitride igniter, you should see 11-17 ohms, but if your furnace has a carbide igniter, you should see 50-100 ohms.

If the reading is outside these parameters, you should replace the igniter. For best results, test the igniter when the igniter is cold, and the furnace isn’t firing.

Check the flame sensor.

To check the flame sensor, you need to hook up your multimeter in series with the flame sensor and the sensor wire. You should then fire the furnace in a heat cycle. If the flame sensor is working properly, your readings should be 1.5-4 uA.

If the sensor tests less than 1 uA, your flame sensor is having issues, and it’s a matter of time before it stops sensing completely.

Inspect the heat exchanger for excessive rust, cracks, and holes

There is nothing that beats visual inspection, but you will need to be cautious when doing it so you can pick all the problems. To pick all the issues your unit might be having, don’t shy from using inspection cameras, dye penetration inspection systems, and other tools that will help you pick as many issues as possible.

Inspect the metal flue for rust or holes and move with haste and replace them if any is present. Remember, using the appliance with these defects, you will be putting yourself and your family at great risk.

Check the system’s static pressure.

Determine whether you are working on a system with a variable speed or non-variable speed motor. The cool thing is, it’s easy to tell. A system with a non-variable speed motor will have a maximum design total external static pressure of 0.50-in.wc. In contrast, a system with a variable-speed motor will have a maximum design ESP of 0.80-in wc.

Once you know the type of system you have, you can now set the correct static pressure.

Undertake a combustion analysis

Start your combustion analyzer while you are outside your home, so you have the correct calibration. When starting your furnace, measure and record the highest CO level during the first 60 seconds of operation.

The CO level will range from 100 to 400 ppm on a natural draft furnace and 100–1000 ppm on a 90% condensing furnace.

If your furnace is operating properly, the CO level should fall below 100 ppm within three minutes after starting the furnace. The operating CO levels should be between 0 and 99 ppm then remain stable.

If your CO climbs during the run cycles, it means you have a problem in your hands that you should address as soon as possible.

Check and adjust the gas pressure.

The best way to measure the gas pressure is to clock the meter to verify that the orifice is the proper size and set the correct gas pressure. The cool thing is most furnace manufacturers list in their installation manuals. For natural gas furnaces, the range is 3.2-3.8. wc.

Since it’s not easy to have the proper assortment of burner orifices, you can achieve proper combustion for maximum safety and efficiency by adjusting the gas pressure.

Inspect the furnace for gas leaks

Gas leaks are one of the most popular problems with gas furnaces. Thankfully, you can easily detect the leaks using soap or electric leak detectors. You should note that the leak detectors will produce false positives from certain pipe dope brands and soap bubbles, so be cautious when using them.

Work with an experienced contractor.

While you can do some inspections by yourself, it’s best, you leave the complex work to an experienced furnace repair service Long Island. In addition to the contractor inspecting your appliance, he will also repair the faulty areas and recommend ways to keep your appliance in the best possible shape.

One of the best places to find an experienced professional is from friends and relatives. If none of your friends know of a contractor, try your luck online.

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