A home with natural gas hookups likely uses gas to power the furnace as well as the stove. In your HVAC career, you’ll encounter a fair number of gas heat furnaces that need repairs or maintenance. Since these heating systems work quite differently from electrical furnaces, it’s important to know how both should typically work and the crucial differences in their makeup and functions.
A gas heat furnace has its pros and cons compared to an electric heating system, as well as significant differences in energy efficiency and how the system works. A gas furnace also has the potential to be dangerous to the occupants of the home if not installed or repaired correctly. Before you start work on a gas furnace, keep yourself well-informed of what to expect and how to handle the machine.
How Gas Furnaces Work
Gas furnaces usually run on natural gas piped into the home from a utility company. If the home doesn’t have natural gas hookups, the fuel will likely be propane from specialized tanks. A propane provider will periodically visit the home to refill the tank and keep the heater running.
Propane typically enters a furnace gas valve at a maximum of 11 inches of water gauge pressure as measured by the proper manometer. Once the propane furnace is running, the actual manifold pressure is usually about 10 inches. Natural gas pressure tends to be about the same amount, averaging about 10.5 inches at the entry point. However, when the furnace is running, the manifold pressure of natural gas will drop to about 3.5 inches of water. Check the nameplate on the furnace to determine which pressure level you should be seeing.
If you take a look at a gas furnace, you’ll see the box is maybe 4-5 ft. long and contains a fan and the furnace itself. One end connects to the duct coming from the filter grill. The other end of the furnace connects to the AC evaporator coil. The fan pulls air from the air filter and, if the furnace is running, it warms the air below and sends it along the ductwork throughout the house. Since the heated air passes through the evaporator coil, it’s just as important to keep the AC coil clean in the winter as it is during the summer. A dirty evaporator coil can cause a furnace to overheat and pose a fire hazard.
A gas furnace and its accompanying flue pipe also requires open space around it (typically 30 inches) to keep them both away from potentially flammable objects. This is especially important for the flue pipe since, even with its double-walled material, it can still get very hot. As the exhaust pipe of the gas heater, the flue handles a lot of hot air. The pipe’s sealant must be sturdy to keep hazardous gases such as carbon monoxide from escaping, and the pipe must never be closer than 1 inch to wood or flammable materials or it poses a significant fire hazard.
A properly installed gas heater connects to the thermostat and waits for the signal to turn on. The thermostat receives 24 volts from the red T stat wire and sends the power to the furnace through a white wire, which activates the furnace. The furnace sparks the gas inside to create heat and begin warming the whole house.
Pro Tip: Propane and natural gas furnaces are designed for very specific and very different fuel sources. NEVER try to run a propane furnace with natural gas or vice versa! The differences in pressure will lead to severe problems.
Running a Gas Furnace
When installed correctly, a gas furnace runs like this:
- The combustion fan motor, a special fan that pushes or pulls air through the fire box, activates for about 30 seconds. Any raw gas in the sparking area is flushed out through the roof. A small pressure switch connected to this fan tells the thermostat the fan is running. Once the thermostat gets the signal from the switch that the purge fan is on and has run for 30 seconds without a problem, the next step begins.
- The thermostat checks that all the safety switches are in the proper open or closed positions. Located in several places on the furnaces, these switches detect overheating or other potential dangers. If these switches are in the proper position, the thermostat keeps moving forward.
- The thermostat sends power to the hot surface igniter until it glows red hot. If you have a spark igniter furnace, this is when it starts sparking. The thermostat can even tell if the hot surface igniter is hot or not by measuring how much resistance it gives the electricity.
- Now that the furnace has a spark or red hot igniter, it opens the gas valve and lets in a little gas. As the gas travels past either the sparker or the hot surface igniter, it lights.
- Using a flame sensor, the thermostat verifies that the gas ignited safely.
- The thermostat then activates the main gas and lights the main burners. Now the furnace is fully in heating mode with up to 100,000 BTUs of heat being created.
- Finally, the thermostat turns on the main house fan and start blowing the heated air all around the house. Eventually, the temperature will reach the maximum specified by the homeowner and the thermostat will deactivate the heater. If the thermostat sense any problems or potential dangers, it will immediately deactivate both the heater and gas and potentially place both into lockout mode to prevent an accident.
Troubleshooting a Gas Furnace
One important step in troubleshooting a gas furnace is to pay attention to the circuit card, a computer card inside the thermostat. A diagnostic light on the card will flash at a certain rate to indicate the necessary repairs. Always take note of the flash rate in case you have to reset the light–this is valuable information that helps you determine the problem.
To diagnose the issue, try to ignite the furnace and watch each step as it happens. As soon as you notice the furnace faltering on a particular step, you’ve discovered the potential source of the problem. Work from there to find the answer.
Pay attention to the flue pipe as well. An older, less efficient furnace will likely have a flue pipe that tends to stay very hot and very dry, since about 20% of the generated heat was wasted through exhaust fumes. However, newer high-efficiency furnaces will waste far less heat (to the point that plastic piping is often safe to use for their flues) and thus may allow moisture to collect in the flue pipe. The furnace then collects and disposes of the moisture. These kinds of furnaces are called condensing furnaces. Check your manual and manufacturer’s recommendations to determine the proper type of flue pipe for each heater.
The length of the flue pipe is also important. Calculate the length of pipe extending outside the home based on the roof’s pitch and the manufacturer’s recommendation. If you overcompensate and make the extension far too long, you run the risk of the pipe breaking off in high winds and allowing deadly exhaust gases back into the home. Support the flue pipe very firmly and never make the exhaust portion too long. When the life of your client is in your hands, it’s better to be overly cautious than to just meet minimum standards.
A client’s air filter might also be a cause for concern. To see if the filter is causing the problem, watch the flame in the furnace. A normal furnace flame is bright blue. Any yellow flames indicate incomplete combustion caused by poor air flow through a dirty filter. This is a serious condition that you must address immediately. Until the flame is blue again, the problem is not resolved.
Finally, do you have all the tools necessary to work on gas furnaces? Check your HVAC supplies and make sure you own all of the following equipment:
- Gas pressure tester
- Combustion analyzer
- 3 amp fuses
Above all, remember that while trial and error is typically a legitimate way to learn, it is drastically unsafe to experiment with gas heaters. Even the slightest mistake could lead to potentially deadly consequences for the homeowners. Never take a guess or try to figure out something unfamiliar on your own. Consult an expert or the manufacturer when necessary. An abundance of caution is far better than rushing a job and making a dangerous mistake.
Providing Excellent Work to your Clients
Working on a gas heat furnace presents its own set of challenges that an electrical system won’t have. Fortunately, with the right amount of study and hands-on practice with both kinds of heating systems, you’ll be well-prepared to help your clients keep their homes warm this winter.
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Why is it so important to understand what a normal HVAC system looks, sounds, and feels like? Simply put, you must know normal before you can diagnose abnormal. Adopting this philosophy will have a profound impact on how you see and work on almost everything.
No matter what you are doing, if you know what is normal, you will be much more confident in the outcome. Technicians that don’t realize this tend to make many mistakes, incorrect diagnoses, and improper installations. What impact will this have on your HVAC career?
Normal Isn’t Always Good
It should go without saying that normalcy in an HVAC system isn’t always a good thing. For example:
- It’s normal that most a/c systems are installed incorrectly.
- It’s normal for technicians to ignore superheat and subcool when charging or testing a system
Even if being normal isn’t always a good thing, it’s still important to recognize what a normal system looks like. If you know that most systems are installed incorrectly, it will make you look harder and not assume anything. If you know that most technicians ignore proper charging procedures by ignoring superheat and subcooling, you will take a closer look at that even though you may be there for something entirely unrelated to the refrigerant charge.
Sometimes knowing normal is knowing how something reacts when it fails. For example, if a liquid line drier starts to clog up, it’s normal for a temperature drop to be detectable from the inlet to the outlet side. It’s also normal for a clean drier to not have a temperature drop. Both of these are the norm for that particular situation, but both equally important to know.
On the other hand, two seemingly opposite functions could also be normal. For instance, an evaporator coil will produce a large amount of water if the air is high in humidity, and none at all if the weather is dry. If you don’t know the difference, you might misdiagnosis a problem based on incorrect knowledge of what the system is supplied to do. Just the fact the coil does or does not produce water means nothing if you don’t understand the differences.
Pro Tip: Even if you notice fluctuations in certain HVAC functions, don’t assume that means there’s a problem. The system may be designed to handle or cause those changes. Stay informed of real problems to watch for.
“Normals” of HVAC Compressors
How much do you know about the normal functions of HVAC compressors? Let’s just consider the temperature of the shell of the three compressors. The scroll on the top of the compressor should be very hot since that’s where the head discharges into the dome. In fact, the entire dome should be very hot anytime the unit is turned on, while the sides are cooled by suction gases and will not be nearly as hot. Since the reciprocating compressor is also cooled by suction gases, you should only notice heat where the hot gas line leaves the shell.
If a technician touches a rotary and assumes it is overheating because he confuses it with a scroll, they’ll misdiagnose a system issue and perform unnecessary work. Similarly, touching a hot reciprocating compressor and assuming it is operating normally because you don’t know better will allow a potentially severe problem to get worse.
Know What a Normal HVAC System Looks Like
It’s been said that “You must know normal before you can know abnormal”. This saying is particularly true in an industry that deals with troubleshooting. The first step toward identifying a problem is knowing what normal operations should look like and what any deviations from the norm could mean.
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Customers have high standards for anyone they choose to hire for HVAC work. After all, few people would debate that a well-maintained ventilation system is essential for comfortable living in a hot city like Houston. Fortunately, there are a few things you can do to prove that you’re worth your clients’ trust.
Signs of a Good HVAC Contractor
Just as clients look for potential red flags when searching for someone to hire, they also look for “green flags”–in other words, good signs about a potential hire. By doing your best to know and display those green flags, you can earn yourself more loyal customers! Here are a few of these good signs:
- Fully in compliance with applicable laws
- State-of-the-art HVAC units and equipment
- Quality work and service
- Written warranty
- Emergency services
- Excellent testimonials
1) Fully in Compliance with Applicable Laws
Most states require extensive licensing for anyone working in the HVAC field or handling coolants in their work. In addition to providing proof of a license, make sure you’re familiar with the EPA’s standards for indoor air quality and can demonstrate your adherence to them in your work. Your clients will be glad to know they can trust you to comply with legal requirements and maintain a high standard in your work.
2) State-of-the-Art HVAC Units and Equipment
Clients want the best for their home HVAC systems, even if that means the units they end up purchasing are expensive. A quality air conditioning or heating unit will last a long time, require few repairs, and save the homeowner money on their energy bills. Are you able to offer these exceptional units to your clients? Do you know how to work on them with excellent results?
Pro Tip: Take the time to evaluate your tool collection as well. Does anything need replacing? The quality of your work is directly related to the quality of your tools.
3) Quality Work and Service
Anyone with excellent customer service skills but no knowledge of an HVAC system makes a poor air conditioning technician. Likewise, you can have extensive knowledge of how home ventilation systems work, but without customer service skills, you may not be rehired. Learn to strike the proper balance of excellent work and approachability to best appeal to a wide range of clients.
4) Written Warranty
Even if the HVAC hardware and parts come with a written warranty, what about the work you do on them? Clients will generally feel far more comfortable knowing that hardware and labor alike is backed by a guarantee in writing. Make sure you can provide this for your customers, whether on your own or through your HVAC employer.
5) Emergency Services
A home’s heating and cooling systems are essential to homeowners’ comfort. If the AC stops working in the middle of a hot Houston summer, the HVAC technician had better be available to come and fix it immediately! Offering 24/7 emergency heating and air conditioning services will go a long way toward keeping and retaining clients.
6) Excellent Testimonials
Finally, customers still love seeing good ratings and glowing customer reviews. Make sure to request good reviews from satisfied customers, and reach out to try solving any problems mentioned in negative reviews. The more positive stories you have to share, the better your chances at gaining new customers will be!
Earn Clients Through Quality Services
Ultimately, clients look for a candidate that can provide both quality HVAC work and excellent customer service. If you can show that you are able to provide both, not only will potential new clients seek you out, but your previous clients will also be likely to hire you a second time for future work. Hard work and good service will pay off!
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From time to time, a business or independent contractor find themselves in the unusual position of firing a customer. This is a relatively uncommon occurrence and is usually seen as something of a strange role reversal. However, the ability to cut ties with a customer is a crucial ability to have, particularly for contractors or small business owners.
Yes, you can fire a customer and your business prosperity can depend on it. If a customer is unbearably difficult or clearly trying to take advantage of you, there’s no shame in refusing to provide services to them anymore. Ultimately, this decision will protect your sanity and your business.
How to Know When a Customer Needs to Be Fired
Many customers are finicky, and some are just downright hard to work with. However, it’s not impossible to work with finicky or difficult customers. After all, they still pay you just like the good customers do.
However, there are some customers who are past finicky and difficult and are impossible to work for. This customer will seek you out just to take as much as they can from you in time and expertise, but will never pay you a dime. They generally start the process by telling you how many projects they might have for you once they get this one resolved. This only thing they want is to somehow get you to fix their system for free. In the business world, these kinds of customers are known as “tire kickers”, after people who waste a car salesman’s time by kicking the tires of every car in the lot without actually buying one.
Pro Tip: Anyone who hires you for HVAC work with the promise of dozens of future jobs is just as dishonest as someone who offers to pay an artist in “exposure”. They just want free labor from you–don’t give it to them!
Firing a Customer
Learn how to identify these bad customers sooner rather than later and fire them. Usually, this is done by giving them a price and refuse to work until a check is in your hands. Other times it requires telling them you will not work for them. In extreme cases, it might just mean blocking their number and forgetting about them.
Don’t Be Fooled
Some of the persistent, impossible customers just don’t understand the concept of being fired. Train yourself to not get caught in a tire kicker’s web of promised future work. If you suspect a customer may be a tire kicker, ask for payment or a deposit upfront and see how they react. If your instincts are correct and they’re just wasting your time, fire the customer immediately. Don’t give them time to fool you anymore.
Terminating the Relationship with a Customer
As an HVAC technician, train yourself to distinguish between a difficult customer, a client having a bad day, and a tire kicker. Additionally, remember there’s no shame in refusing to offer services to a particular client because of their behavior. Just make sure you know when to cut ties with a bad customer and how to handle the situation professionally.
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For most people in the past few decades, the ideal life was graduating with a four-year college degree and landing a white-collar job. However, as the cost of college continues to rise and traditional jobs decrease in number, trade schools are beginning to gain popularity once again.
High school students and graduates begin job hunts earlier in life now than in the past few decades, and as the demand for jobs increases, the business world can’t supply them all. Over time, this has led to a general disillusionment with traditional colleges as people turn to vocational school for a guaranteed job upon graduation. Let’s see what trade school can offer that traditional four-year degrees can’t.
Trade schools generally boast a much shorter educational period than traditional college. Some vocational schools take as long as a year and a half to two years, while others finish in a matter of months. The Chris Walters Method can even get an HVAC trainee certified in just 14 weeks! For anyone in a hurry to join the job market, vocational schools are certainly a viable option to finish quickly.
An estimated 97% of Americans have an air conditioning unit in their home, more than 99% have a flushing toilet, and 68% have a dishwasher. The average person will call an expert for repairs when these home fixtures break down. With numbers that high, anyone entering the vocational field can find work on most days since repairs are always in demand. Just make sure you market yourself so people know to look for you!
Pro Tip: Marketing your HVAC skills is possible through word of mouth, email marketing, flyers, and other strategies. How visible can you make yourself?
Entry-level vocational school graduates are beginning to enter the market in greater numbers. For most people looking to begin trade school soon, now is the time to begin marketing themselves are competent vocational workers. The future is bright for anyone entering a blue-collar job!
Trade School Popularity
Trade schools can offer all the practical work skills needed for a specific career path, as well as a promise of an always-interesting workday. Better yet, you won’t spend nearly as much money or time on a technical school education. If you’re interested in a technical or HVAC career path, give tech school a try!
Connect with us to learn more about the advantages of trade school and to sign up for our next set of classes.
In your new career in the HVAC field, you’ll be learning as you go and establishing yourself as a trustworthy contractor. Of course, no one is perfect, and you’re likely to make mistakes along the way. However, there are a few key errors you should do your best to absolutely never make.
Common HVAC Mistakes
As you work to develop your HVAC job, you may find yourself uncertain about some decisions or aspects of your new career. First of all, remember that everyone makes mistakes. However, a few particularly unfortunate mistakes could cause problems for you in the long run. Consider these choices you should absolutely not make in your HVAC work:
- Don’t sell yourself short
- Don’t just focus on the HVAC mechanics
- Don’t rely on “rule of thumb”
1) Don’t Sell Yourself Short
In your early days of business, you won’t be able to charge especially high prices for your services. You’ll still be in the stage of proving yourself to your clients. However, don’t constantly underbid on a job. Remember, the cost of a job is your salary. Don’t feel obligated to bid an unreasonably low price or accept a terrible estimate.
2) Don’t Just Focus on the HVAC Mechanics
On the surface, your clients are hiring you to work on their HVAC units and fix a definite problem. Ultimately, they’re hiring you to enhance their comfort in their own house. If you fix a faulty air conditioning but fail to mention that a poorly done window is causing the cold air to leak out, your clients may face the same problem later. Make sure your clients know what other work may be necessary to completely fix their problem. As an added bonus, you may be able to do some of that work yourself, resulting in a bigger paycheck!
Pro Tip: Don’t try to fix a problem you didn’t study for. Offer to expand your project to include additional HVAC work, but don’t try to fix a client’s broken window.
3) Don’t Rely on “Rule of Thumb”
You’ll rarely encounter two identical homes or HVAC systems. While you may be tempted to rely on what you believe to be universal characteristics between different HVAC units, the truth is that you’ll be working on drastically different equipment almost every time. Study and learn about the myriads of unique HVAC systems and house layouts, not a “rule of thumb” that changes with every change to building styles.
Don’t Make These Common HVAC Mistakes!
There’s no way to predict what you’ll encounter in your new career or the decisions you’ll have to make. However, you can decide ahead of time to avoid these pitfalls when they show up. Don’t allow yourself to make these mistakes! Your new career will thank you.
Join the conversation to learn more about what to avoid as you start your new journey into the HVAC field.