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Home»The Only Furnace Troubleshooting Guide You’ll Need

The Only Furnace Troubleshooting Guide You'll Need


Basic Furnace Troubleshooting

Fixing minor problems is the first step in making sure your furnace works well when the weather turns chilly. By following this technique, you can keep your furnace running efficiently and prevent the need for unneeded service calls. Here are the basic basics that any homeowner should know while troubleshooting a furnace.

Reconnecting the power to the furnace is the root cause of many repair calls. To see whether your furnace has enough power, follow these steps:

Furnace Switch: The furnace switch regulates the flow of electricity directly to the furnace; it is a safety device usually placed close to the furnace or on a wall adjacent to it. Turn this switch to the “on” position. While doing everyday tasks near the furnace, it is easy to mistakenly turn off this switch.

Finding the Circuit Breaker Panel: Most homes have their breaker panels in the basement, garage, or utility closet. Find the designated breaker that is specifically for the furnace. It might be necessary to check each breaker individually or get some assistance if you can’t determine which one is right. To reset a breaker that has tripped, turn it off and then turn it back on again. If the tripping keeps happening, it could be a sign of an electrical problem that needs fixing.

You should also look for indications of electrical damage, such as burn marks or loose connections, in the vicinity of the furnace, in addition to the switch and breaker, to ensure your safety. These could be signs of major issues that are causing the furnace to not only not work properly but also put people in danger.

The thermostat controls the heating system in your home, telling it when and how much heat to produce. If you want to make sure your thermostat is regulating your furnace properly, do these things:

Power and Settings: Turn on the power and check the settings of the thermostat. If the batteries are dead, replace them. The furnace will turn on when the desired temperature is greater than the ambient temperature, therefore be careful to set it to “heat” mode.

Proper Installation: To ensure accurate readings, place the thermostat in a cool, draft-free area, away from any heat sources (such as a kitchen) warm air, and direct sunlight. It could cause the furnace to heat up and cool down at random intervals if not installed properly.

Calibration Verification: A thermostat’s accuracy in reading temperatures is dependent on how well it has been calibrated. Over time, a thermostat’s calibration might wear out. Simply set up a second thermometer close to the thermostat and compare the results to rule out that possibility. It may be necessary to recalibrate or replace the thermostat if there is a noticeable difference.

Keep your furnace running smoothly and efficiently for as long as possible by keeping the air filter clean. To inspect and change the filter in your furnace, follow these steps:

Locate and Remove: Find the filter and take it out. You can usually find it in the furnace’s intake area or on the unit itself. To avoid debris entering the system, turn off the furnace before removing the filter.

Inspect: After taking the filter off, put it up to a light. The filter has to be cleaned or replaced if light is not passing through easily.

Clean or Replace: If the filter is disposable, clean it or get a new one that is compatible with your furnace. If it is reusable, clean it following the manufacturer’s instructions (which usually include washing it with water or vacuuming it) and let it dry completely before reinstalling.

Regular Checks: If you want your furnace to work at its best, you need to check on it often and change the filter if necessary. The type of filter, amount of household dust, and presence of pets or allergies are some of the variables that determine the frequency. A good rule of thumb is to inspect it monthly and change it every three months.

Intermediate Gas Furnace Troubleshooting

In the intermediate level of troubleshooting, you’ll look more closely at the furnace’s most important parts to see how they work. A little more technical knowledge is needed for this procedure. To help you with this troubleshooting, here are a few steps:

In older furnaces, the gas burner is started by lighting a small, steady flame called the pilot light. Your furnace’s safety depends on the pilot flame and its correct operation, so be sure to check it often.

Examine the Pilot Light: You can usually find the pilot light close to the base of the furnace. Make sure it’s illuminated. A pilot light that goes out too soon could be a sign of gas pressure issues, a clogged orifice, or a thermocouple malfunction.

Relighting Procedures: If your furnace’s pilot light has gone out, you can relight it by following the steps outlined in your owner’s handbook. To do this, most gas stoves have a “pilot” option, which requires you to press down on the valve when lighting the flame and then hold for around 30 seconds to keep the flame going.

Checking Gas Supply: Make sure the main gas supply is turned on by checking that the valve is in line with the gas line. It may be necessary to visit a professional or inspect the gas line for any obstructions or bends if the pilot light continues to malfunction even after opening the gas valve.

One of the most important parts of your heating system, the gas valve regulates the amount of gas that flows into the furnace. Furnace gas valves that aren’t working properly can make your furnace not work.

Inspect for Signs of Wear: Examine the gas valve for any indications of corrosion or wear. A gas leak could be indicated by the sound of hissing. If you apply a soap solution to the fittings, you can see if there are any leaks since the water will bubble up.

Operational Check: Watch the gas valve react as the heating cycle begins. Timely functioning is expected. There might be an issue with the electrical connections, gas valve wires, or the valve itself if it opens slowly or doesn’t open at all. Verify that there are no breaks or disconnections in the wiring.

Seek Professional Advice: Since gas valves and their safety mechanisms are complex, it is best to have a professional look at any problems you suspect. To eliminate potential hazards caused by improper installation, it is recommended that a professional replace the faulty gas valve.

A well-functioning furnace will have a steady heating cycle and a bright flame in the burner.

Assess Flame Quality: A stable flame in a furnace, mainly blue with a little yellow tip, is an indication of good health. If you see other hues, such as orange or widespread yellow, it could be because of dirty burners or an incorrect air-to-gas ratio, both of which can cause incomplete combustion. Burners should be kept clean and clear of any obstructions.

Heating Cycle Observations:: Be mindful of the on/off cycles of the furnace as you observe the heating cycle. Oversizing the furnace, an obstruction in the filter causing it to overheat, or a broken thermostat are all potential reasons for frequent brief cycling. Be careful to record how long it takes for the furnace to reach the desired temperature and whether it turns off after that.

Evaluate Thermostat and Control Board: Verify that the thermostat is operational and that the settings are correct by examining the control board. If the furnace turns off before the temperature is reached, you might want to check the thermostat with a multimeter or think about getting a new one. Also, look for damage or error messages on the control board; these could indicate electrical problems affecting the heating cycle.

Braeden RigbyBraeden Rigby
19:47 25 May 24
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premnath parthibanpremnath parthiban
14:52 23 May 24
I spent almost one year to find the best HVaC replacement company and finally landed with Comfort union .I initially thought it was a small job but then realized the magnitude of work and effort it goes into it ..Asif initially came to my house , explained to me everything in detail including what is code of guidelines expected by city of Calgary , that showed his knowledge on the whole process ..Then came his brother Moore for installation - you will never find such a wonderful person who knows in and out of the HVAC and moreover the most patient person I have ever seen .. he did the whole installation with absolute craftsmanship and love for the work he did .. the best part was his perfectness and every work he did was so perfect and tidy !Finally, came Khan ji - to do the final inspection to add perfectness over the perfectness carried by Moore .. He did inspection and made sure everything was 200% correct ..Overall , I would recommend comfort union over any other service provider …Replaced my furnace , water tank and my humidifier …
JJ YanJJ Yan
02:22 22 May 24
Muhamad and Darryl did an excellent job on installation of our new Bradford White 75 gallon water heater. Extremely professional and hard working. They not only just did the work, but also explained the procedure thoroughly and maintenance focus points. Kept the work place tidy and in order. Highly recommended to everyone. JJ
mr2008 2.0mr2008 2.0
04:08 12 May 24
excellent carrier furnace and air conditioner installation, highly recommend to others
20:52 06 May 24
It was great to see a father and son team work so professionally in the delivery and installation of our new Bradford White water heater. Thanks team for a wonderful job.
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03:21 30 Apr 24
Friendly staff and did amazing work with carrier hvac
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02:59 30 Apr 24
Amazing work. Good work on AC installation. Competive rates
Fast response due to the urgent occasions. The team is very experienced. Highly recommended!
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23:04 06 Apr 24
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18:28 02 Apr 24
Great and reliable service.
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10:11 01 Apr 24
Best reasonable and quick in their response.
E TanE Tan
01:45 31 Mar 24
I recently hired Comfort Union to install a new hot water tank in my home, and I couldn't be more pleased with the results. They went above and beyond to ensure that the installation process was smooth and hassle-free from start to finish.Daryl's expertise and professionalism were evident from the moment he arrived at my home. He took the time to assess the layout of the space and discuss the best options for the installation, providing valuable insights and recommendations along the way. His attention to detail and commitment to quality craftsmanship were truly commendable.Throughout the installation process, Daryl and Mo worked efficiently and diligently, ensuring that everything was installed correctly and functioning optimally. They were respectful of my home, taking care to clean up any messes and leaving the work area spotless once the job was complete.I would like to extend my sincerest thanks to the entire team at Comfort Union for their outstanding service. Thanks to their expertise and dedication, I now have a reliable water heater that meets my needs perfectly. I would highly recommend Comfort Union to anyone in need of plumbing services – their professionalism and quality workmanship truly set them apart.
Ayaan DawoodAyaan Dawood
06:38 10 Mar 24
Imran Ahmed KhanImran Ahmed Khan
06:04 10 Mar 24
Maggie VaccaroMaggie Vaccaro
21:26 05 Mar 24
Quick response for appt. Came over and got all work done.Will call them again and will recommend them to others. Thanks!
Ashirul PatelAshirul Patel
22:57 26 Feb 24
We had great experience. They work out an efficient way to solve our furnace issues while maintaining the minimum cost.
Rakesh SachdevaRakesh Sachdeva
04:44 10 Feb 24
Muhammad is very professional and very cooperative. He has completed the work as explained. Everything was completed on same day we had issue. Very responsive.
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22:28 08 Feb 24
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02:33 07 Feb 24
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Matt MelliesMatt Mellies
21:21 22 Jan 24
I had an issue with my furnace, went to reset my main breaker to power cycle trying to troubleshoot it... Breaker crapped out so I was sitting on an electrical, and furnace problem.Gave these guys a call and they were able to come out within 2 hours. Required a full main breaker replacement, and new gas valve on my furnace. They diagnosed it in only a couple hours, and fixed everything the same day.Had a great experience, the technicians that showed up were professional, and very knowledgeable. I'll definitely be using these guys when I eventually have replace my aging furnace.
Sharif ZayedSharif Zayed
00:15 22 Jan 24
Khan was so kind and considerate to help me during the -45 C calgary weather. We decided to replace our old furnace with newer and advance features choosing Carrier Furnace. We received the quote from Comfort Union which was competitively priced and the job was completed next day. Thanks.
Syed Zaigham RizviSyed Zaigham Rizvi
05:29 18 Jan 24
Had a bit of a crisis with rental property heating system in Calgary, our Goodman furnace gave out and had countless furnace repairs over the years. They got a new Carrier furnace installed quickly and very competitively priced compared to other carrier dealers. Wasn't expecting such quick service in the cold months. Definite recommend!
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00:23 06 Jan 24
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Agit KokuAgit Koku
21:40 13 Apr 23
I recently had Comfort Union come to my home to fix an issue with my hot water tank's pilot issue. Not only did the technician promptly fix the issue, but they also took the time to clean out my drain as a courtesy. I was impressed by their attention to detail and their commitment to providing excellent customer service.I would highly recommend Comfort Union for anyone in need of plumbing services.

Advanced Furnace Troubleshooting

When basic troubleshooting fails to fix furnace problems, it’s important to explore more complex diagnostic methods. The blower motor, pressure switches, and heat exchanger are just a few of the many systems in your furnace that these advanced troubleshooting steps cover in depth.

Operational Check: As a first step in the operational check, make sure the blower motor starts up with the furnace. Verify that it is getting power by checking the connections and looking for blown fuses or tripped breakers if it isn't working. Keep an ear out for unusual noises, such as grinding or screeching, that could indicate lubrication is needed or that the motor bearings are failing.

Blower Motor Speed Issues: While heating, the blower motor should change speeds accordingly. Possible causes of adjustment failure include damaged capacitors, malfunctioning motor control boards, or problems with the wiring. If you want to know if you need to replace the capacitor, you can test it with a multimeter and compare the results to the manufacturer's requirements.

Pressure Switch Function: The pressure switch is an essential safety feature that checks the venting system for obstructions before starting the furnace. It is possible that the pressure switch is faulty if the ignition is not constant. You can tell if the switch is working by measuring its continuity while it's in use with a multimeter. To ensure the switch is functioning properly, check the tubing for any obstructions or gas leaks.

Gas Flow Regulation: A well-functioning furnace relies on the correct flow of gas. Make sure the gas supply is turned on and the furnace gas valve is completely open. Check that the gas pressure at the manifold is following the furnace's requirements by measuring it using a manometer. Problems like a broken gas valve coil or fuel line blockages can be to blame for pressure variations.

Visual Inspection: Look for any damage, such as cracks, rust, or holes, on the heat exchanger that could cause carbon monoxide to leak out. Check out those hard-to-reach places with the help of a flashlight and a mirror. Repair by experts is usually required when damage is discovered.

Burner Maintenance: To maintain the burners, take them out and wipe them down whenever they get dirty. Using a vacuum cleaner and a wire brush, remove any debris. Before reinstalling, make sure they are dry. After you switch on the furnace, make sure the flames on the burner are stable and blue. Incomplete combustion, indicated by yellow or uneven flames, necessitates modifications or expert inspection.

Flue and Vent Inspection

Safety Check: A safety check should be performed regularly to ensure that the vents and flue are free of obstructions or leaks that may be caused by weather or foreign objects. When the flue is obstructed, gas can back up into the house, which can be quite dangerous. Take prompt action to fix any vent leaks.

Control Board and Sensors

Inspect the electrical components by looking for corrosion or damage on the control board. Check for continuity with a multimeter, and if you find any damaged terminals or wires, replace them.

Functionality of the Sensors: Limit switches and flame sensors are among the sensors that the furnace uses to keep tabs on how it's running. To avoid dangerous furnace shutdowns or unusual behavior, clean or replace sensors that are rusted or covered in soot.

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