Solving Common Gas Furnace Problems

Hi, my name is Eric Noack. I'm an HVAC technician at ABC Plumbing, Heating, Cooling, and Electric.  In this month's blog article I'm going to talk about some of the most common gas furnace problems we encounter and some of the things to look for when your gas furnace is not heating properly.

The following are some of the topics covered in my series of videos on furnace problems at About.com.

Thermostat Problems

The first thing to check is the battery. Most digital thermostats have a battery indicator on the display. If you see an icon in the display asking for a battery, follow the manufacturer's instructions and replace the battery with an appropriate size.

If you see no display at all, check the power to the furnace. This particular thermostat has a sealed battery in it, and it's not replaceable.

If you've checked the battery, you've checked the power supply, and your thermostat is still not operating properly, it's likely that you're just going to have to replace your thermostat. It's important to understand how your thermostat operates when it's normal, when everything is right. If you're familiar with the proper operation of your equipment, then it's going to make it easier if you notice something acting unusually and you can call ABC a proper diagnosis.

Mismatching Furnace and Thermostat

Your home's gas furnace needs to be paired with the correct thermostat to work properly; if it isn't, you could run into problems.

Thermostats have to be matched to the system based on the type of furnace that's used and the capacity and capability of that furnace. The best way to make sure you're going to have a thermostat that matches your system is to get it from an HVAC professional.

Electronic Ignition Furnace Problems

To determine what type of ignition system you have, open the front of the furnace and initiate a call for heat. Observe what happens in the burner area. If there's a very small flame that starts first, and then ignites all of the main burners, that's an intermittent pilot type of ignition. If the ignition happens and the main burners come on immediately, then that's a direct ignition.

Once you determine which type of ignition system you've got, if you see it operating in a way that's not correct, it's best to call an ABC service technician as soon as possible. It's important that your are is aware of how the system is supposed to operate when everything is normal. So that way when things do change, you can be aware of it and call for service before it becomes a bigger problem. It's going to help maintain the equipment, keep it lasting longer, keep it safe, and also reduce your energy costs.

Furnace Has a Noisy Operation

Squeaks, rattles, and rumbles are some of the things that we hear from furnaces. In the case of a squeak, it can be related to a motor failing or just making noise. Rumbling and rattling can be caused by an out of balance blower wheel caused by debris or just age or just being dirty. Early gas furnaces used a motor with a belt to drive the wheel. That's the blower that moves the air into the house. All modern furnaces use a direct drive blower that's permanently lubricated. It doesn't require any lubrication or maintainance on that.

Squeaks and squeals can also happen from air leaks. There can be a leak in the duct work or around the furnace somewhere that's allowing a small amount of air to leak in or out causing a whistling or squeaking sound. If you suspect that a high-pitched squealing or whistling noise could be coming from the air flow, what you want to do is check some of the gaps or joints where the sheet metal is connected. Those are the likely sources where that can happen and it can be simply sealed up with tape or a piece of putty or something like that. Sometimes something as little as this door being out of alignment can cause a squeal or a squeak and you can just move it a little bit or just make sure it's firmly placed where it should be.

So when you look at the burners on a furnace, you can kind of judge the condition. If you see any kind of dust, lint or other kind of dirt in the furnace, that could be clogging one of the burners and causing excess noise in a furnace. In that case, it's really important to get a professional out to do a proper cleaning on the furnace for you. Knowing a little bit about your system and being educated about it is the best way to stay on top of it and avoid breakdowns. A lot of times when homeowners hear the system operating in an unusual way, they can have us come out and take care of it before it becomes a bigger issue.

Furnace Blower Does Not Turn Off

The first thing to check is the fan switch on the thermostat. "Auto" means that the fan should only be running to try to heat or cool the home to try to match the thermostat setting. If you see the thermostat fan switch set to "on," or "low," "medium," or "high," then you're going to have continuous fan operation.

The next thing to look at is your furnace filter. If you find a clogged filter, it may have caused damage to the limit switch. What the limit switch does is it senses the temperature inside the furnace. If it sees a temperature that's too high, then it shuts off the fire as a safety and only will allow it to come back on once it's cooled sufficiently. If the filter has been clogged for too long, then it may have damaged that switch to the point where it needs to be replaced. In this case, the furnace high limit is a small button type device that's got two wires connected to it. Every furnace is a little bit different. Some of them have more than one limit, and some of the limits look very different. If that limit switch is failed, it's very important to find the source of why it failed and not just replace the switch. It's a very important safety issue.

Furnace Cycles On and Off Too Frequently

If you notice the frequency of the heat cycles becoming too short, that's an indication of a problem with your system. The first thing you want to check is the fan switch on the thermostat. In this case, it's up here in the display and it says "auto." Now, "auto" means that the fan should only be running to try to heat or cool the home to try to match the thermostat setting. If you see the thermostat fan switch set to "on," or in this case "low," "medium," or "high," then you're going to have continuous fan operation.

If your filter has been in the furnace for a long time and its gotten very clogged, it can cause the furnace to what we call cycle on limit. That means that instead of heating continuously, the flames turn on and off because the unit is overheating due to that clogged filter.

The important thing with filters is watching the air flow direction. There's always an arrow that tells us which way the air should flow through the furnace. On most furnaces, people have drawn arrows that tells you which way the air flow direction should be.

Furnace Does Not Produce Enough Heat

One of the most common sources of this kind of problem is a clogged filter. It's very important that you check your filters regularly and change them frequently for good furnace operation and best efficiency. The second possibility is that the furnace was not sized properly, meaning that it doesn't have enough capacity to keep the home warm. It's important that a heating and air company size the equipment for the capacity needed to keep your home warm. Another possibility, though it's pretty rare, could be that your burners could be clogged to the point where it's not allowing the furnace to create enough heat and meet its full capacity.

Furnace Does Not Heat

Some possible causes of that are: thermostat not adjusted properly, the power going to the furnace could be shut off, the gas going to the furnace could be shut off, or the pilot light could be out. A couple things to check with the thermostat: Now, the first thing to remember is that everybody's thermostat is going to be different. In this case, when the red light is on, that means that it's in heat mode, so it's ready to heat the house. The next thing to check is to make sure the set point is higher than the room temperature. So if we raise that set point above the room temperature, that's going to turn the heat on.

Furnace Pilot is Out

Some of the common sources of a lost pilot light are a failed thermocouple, a strong draft, or a clogged orifice to the gas supply to the pilot light. A thermocouple is a device on a standing pilot system that proves the flame to the gas valve and allows gas to keep flowing as long as there's a flame sensed. It's probably best if you have a professional check it out, clean it and verify that it's working properly. Now, the thing to keep in mind is most modern furnaces don't use a standing pilot light anymore.

With the arrival of cold weather in the Chicago area comes the inevitable rise in home heating bills. ABC has come up with some easy ways to save energy this winter and keep that heating and electric bill in check.

Check For Peak Utility Hours

Your local electric utility may have peak hours when rates are higher as well as hours when they are be lower.  If so, change when you use major appliances like dishwashers, washing machines and hot water.  You may be getting charged extra for electricity at certain times of day and not even know it.

Zone Your Home

Instead of using your home's central heating system and furnace all day long, opt for room heaters that you can use to heat just one room at a time.  This works great if you spend most of your day in a home office or for night time when your're only in the bedroom.

Switch To Energy Star Appliances

By choosing to replace your older appliances with Energy Star rated appliances you can become 15 to 30% more energy efficient. Energy Star rated appliances will also increase your home’s market value considerably.

Let The Sunshine In

On sunny days keep your blinds open all day long so your home can soak in the free heat of the sun.  Close them again at night to keep heat from escaping.

Install Energy Efficient Curtains

Putting up energy efficient curtains to seal in heat can make a very big difference in the amount of energy you use for heating your home.

Use a Programmable Thermostat

You'll never forget to turn down the heat when you leave for work or go to sleep.

Change Your Furnace Filters Regularly

As furnace filters get dirty your furnace has to work harder to push air through, meaning more energy is consumed.  Change your furnace filter once a month to help your furnace – and your family – breath easier.

Turn Your Hot Water Heater Temperature Down

Many water heaters are set to 140 degrees but most homeowners can easily turn their water heater down to 120 degrees and not even notice the difference.

Seal Off Your Chimney If Its Not Being Used

If your chimney is just for show, than make sure to seal it up.  Otherwise it's a large hole taking the heat right out of your home.

Reverse Your Ceiling Fans

Change your ceiling fans to the reverse setting to circulate the hot air back down to where you want it.

Close off unused rooms. If you aren’t spending time in them, seal them off for the winter and reduce the volume of air that you're heating.

The causes of low water pressure are many, from simple fixes to more complex water supply problem. The following are some helpful tips to diagnose and fix some of the most common causes of reduced water flow.

Check Your Faucet Aerators

Mineral deposits and debris can cause faucet aerators to become dirty over time, eventually restricting the flow of water.  By routinely removing and cleaning your faucet aerator screens you can keep the water flowing freely. White vinegar can be used to dissolve the mineral deposits on faucets and shower heads. Simply submerge them overnight.

Check Your Shower Head

You can find inexpensive, high-pressure shower heads at your local hardware store, and that could be all it takes to make your shower flow better. If your shower head has a low-flow fixture in place, try swapping it out with a regular shower head fixture to increase the flow of water.

Check the Water Supply Valves

If someone in your home has turned off and then turned on a water supply valve in your home recently, it may not have been returned to the fully opened position.

Advanced Solutions For Low Water Pressure

If you've checked the techniques above to increase your home's water pressure with little success, ABC can help with more problematic water pressure problems.

One solution is a home water pressure booster. A water pressure booster is simply a water pump that works with your home's existing water supply to increase water pressure.

ABC can also help find more serious causes of low water pressure problems. If you have a water pipe that is leaking, it will affect the water pressure in your house significantly (while raising your water bill). Try turning off the water supply both inside and outside your home, then check your water meter. Check the water meter once more a couple hours later to determine if the water usage has increased. If so, you probably have a leak that needs to be located and repaired.

Another option is to increase the size of the main pipe supplying water to your house. See if you can determine what type of water pipes you have in the home and running to your water meter. Pipe size is an important factor in the amount of water pressure you'll get in your home. The larger the pipes, the more the water pressure, so you may want to consider increasing the size of the main pipe servicing your house.

Sealing your home's attic, outer walls, doors, windows, and floors is often the most cost effective way to improve energy efficiency and your family's comfort. With careful attention to drafts and under insulated area of your home, can save up to 20% on heating and cooling costs by sealing and insulating.

Follow These Three Energy Saving Improvements:

• Seal air leaks throughout the home to stop drafts
• Add insulation to block heat loss in winter and heat gain in summer
• Choose an ENERGY STAR® qualified furnace, water heater and air conditioner

Some air leaks are easy to find because they can be felt — like those around windows and doors. But holes hidden in your attic, crawlspace, and basement are often a bigger source of energy loss. Sealing these leaks with caulk, expanding spray foam, or weather strip will have a significant impact on your family's comfort and reduce your utility bills.

Will Sealing My Home Affect Indoor Air Quality?

There is often a concern about sealing a house too tightly; however, this is very unlikely in most older homes in the Chicago area. Some fresh air is needed for good indoor air quality and there are specifications that set the minimum amount of fresh air needed for a house.

To be safe, after any home insulating and sealing project, have an ABC home comfort specialist check to make sure that your home's combustion appliances (gas- or oil-fired furnace, water heater, and dryer) are venting properly.

Choosing the Right Insulation For Your Home

Insulation will keep your home warmer in the winter and cooler in the summer. There are several common types of insulation — fiberglass (in both batt and blown forms), cellulose, rigid foam board, and spray foam. Reflective insulation (or radiant barrier) is another insulating product which can help save energy.

When correctly installed with air sealing, each type of insulation can deliver comfort and lower energy bills during the hottest and coldest times of the year.

Insulation performance is measured by R-value — its ability to resist heat flow. Higher R-values mean more insulating power. Different R-values are recommended for walls, attics, basements and crawlspaces, depending on your area of the country. Insulation works best when air is not moving through or around it. So it is very important to seal air leaks before installing insulation to ensure that you get the best performance from the insulation.

To get the biggest savings, the easiest place to add insulation is usually in the attic. A quick way to see if you need more insulation is to look across your uncovered attic floor. If your insulation is level with or below the attic floor joists, you probably need to add more insulation. The recommended insulation level for most attics is R-38 (or about 12–15 inches, depending on the insulation type).

Seal Air Ducts

In houses with forced-air heating and cooling systems, air ducts distribute heated and cooled air throughout the house. In a typical house, about 20 percent of the air that moves through the duct system is lost due to leaks and poorly sealed connections. The result is higher utility bills and an uncomfortable home, no matter how the thermostat is set.

Because some ducts are concealed in walls and between floors, repairing them can be difficult. However, exposed ducts in attics, basements, crawlspaces, and garages can be repaired by sealing the leaks with duct sealant. In addition, insulating ducts that run through spaces that get hot in summer or cold in winter – like attics, garages, or crawlspaces – can save energy.

Choose ENERGY STAR® Heating & Air Conditioning Systems

If you are replacing your furnace and air conditioning equipment,ABC will installs your new system according to ENERGY STAR quality installation guidelines. This includes a thorough inspection of your duct system, including proper sealing and balancing of ductwork, to help ensure that your new system delivers the most comfort and efficiency.