The gas valves are one of the most essential parts of your furnace. If the gas valve fails, the furnace shuts down and stops distributing warm air, causing discomfort. This Best Furnace Gas Valve covers everything you need to know about the furnace gas valves and how to maintain them, so you can keep your furnish running well.
What is a Furnace Gas Valve
In general, a valve is a component used to control the flow of fluid. In your furnace, the gas valve controls the flow of gas through an exhaust pipe. It opens and closes, allowing the gas to flow to your furnace’s pilot light and burners.
Pilot lights are small burners that first lits once you turn on your furnace; they slowly heat the rest of the burners as they ignite, and the house eventually begins to warm up.
How Does the Furnace Gas Valve Work?
Essentially, two valves make up your furnace’s gas valve:
- The primary (safety valve); and,
- The secondary (main valve).
The safety and main gas valves are in a series position, and they operate by electromagnets. The primary gas valve distributes gas to the pilot light. A pilot light is the smallest burner that’s first lit when you turn on your furnace.
The secondary gas valve then allows gas to flow into the rest of the burners. The thermocouple generates the power in the furnace. The thermocouple is also immersed in the flame of the pilot light.
The furnace gas valve closes if the thermocouple does not receive enough heat to heat the burners. This cuts off the gas supply to the pilot light. Furthermore, the thermocouple serves as a safety device. It prevents gas from accumulating in your home.
After the thermocouple’s approval, the thermostat will now call for heat. The heat gets distributed to the burners. Your house gets warmed up as they burn; the gas valve opens and closes during this process, which is how the furnace maintains your desired temperature. It also regulates the pressure of gas flowing into your furnace.
Choosing the Best Gas Valve?
Choosing the best gas valve for your furnace depends on a few factors. It is best to consult with a trained professional. They will help you decide which gas valve is best compatible with your furnace.
However, here are five factors you should consider when getting a gas valve:
- The valve size and type – Make sure you choose the right type of valve for your furnace. You can check the back of your old valve for details.
- The construction’s materials – The gas valve materials need to be compatible with the gasses that flow through them. Make sure to check and verify the chemical compatibility requirements.
- Performance Requirements – Find out and get the right temperature and pressure ranges to install the valve.
- Special Requirements – Check and ensure if the new valve has any special requirements. Verify the response time and cracking pressure required to open the valve. Sometimes when mistakes like this are made, the valve may not work as expected.
- Maintenance – Lastly, find out about the maintenance requirements. This notifies you of what you’re going to be dealing with.
Top Furnace Gas Valve Brands
Getting a HVAC product from a reliable brand is extremely important, especially for vital devices like the gas valve. The brands you get it from determines whether or not things go according to plan.
Below is a list of Top 11 furnace gas valve brands.
- EMERSON WHITE RODGERS
- A.O. SMITH
- RHEEM RUUD
- HEIL QUAKER
How Much Does a New Gas Valve Cost?
Typically, the price of a furnace gas valve ranges from $200 to $600 (prices in United States dollars). But, this depends on your furnace type, how old it is, and the type of gas valve you’re getting. However, this price may or may not include the installation fee depending on the agreement between you and your dealer.
Suppose you want the gas valve to be replaced by an HVAC company, it is likely to cost, between $350 to $595. This includes the installation fee. Ordering the valve online and replacing it yourself can be as low as $65. That is if you can do it yourself.
Types of Furnace Gas Valve
There are three basic types of gas valves for furnaces. Although they each have their unique characteristics, they all perform well. However, the main difference between all three of them is how easy they are to operate.
Below is everything you need to know about these gas valves.
Gas Chain Valve
The gas chain valve is one of the oldest furnace gas valves on the market. It’s called a chain valve because it looks like it. The gas chain valve has only four components which are:
- A safety control;
- Solenoid valve; and,
- Manual valve.
All three of these components with the regulator are in a series position on a long metal shaft, making it look like a chain. Because it does not come with an automatic valve, you always need to turn the valve handle in order to open or close the flow of gas.
- Affordable – Because it’s one of the oldest, the gas chain valve is possibly the cheapest.
- No Automatic Operator – You can only operate it manually.
- Stressful – A little inconvenient to operate.
Solenoid Valve and Pilot Safety
Unlike the gas chain valve, the solenoid does have an automatic valve. As described above, it comes with the pilot safety valve. However, it only opens when the furnace calls for heat. Because of this, there can only be gas flow if all the valves in the system are open.
Also, the pilot safety can only remain open until the thermocouple gets enough heat. As mentioned above, the pilot flame supplies heat to the thermocouple. An electromagnetic current powers the pilot light. Although you manually re-ignite it yourself if you want.
- Fast response timeThe solenoid gas valve can open and shut within half a second. This helps the furnace to maintain your desired temperature by supplying heat where it needs to and stopping where there is enough heat.
- Low power consumption:Over the years, the solenoid gas valve has been improved to make it very efficient.
- Convenient:It is very convenient to use because it has an automated control system.
- Safe to Use – When dealing with high maintenance toxins, gasses, and fluid, a constant visit to the unit is not very secure. The Solenoid valve helps limit the amount of time you have to visit the unit.
- Versatile and Adaptable – You can install the valve in a lot of locations. It can also be installed vertically and horizontally.
- Sensitive to Voltage – Solenoid valves can have problems when the voltage feed being passed through is either low or too high. This can be a simple human mistake.
- Risk of Valve Closure If the magnetic field isn’t set up correctly, the valve may partially close.
- Weak Coil –If the voltage settings are not correct, it can wear off the valve. This can break the coil, which means you have to change it.
Combination Gas Valve
The combination gas valve is the newer version of the gas chain valve. It performs all the functions of the gas chain.
The combination gas valve comes with;
- A valve handle;
- Electric terminals; and,
- A solenoid valve.
By now, you might be wondering, “If the combination gas valve does the same job as the gas chain, what’s the difference.” Well, the difference is that all components of the combination gas valve come in one package. Meanwhile, the gas chain valves come in parts and need to be assembled on a shaft.
- Convenient – Unlike the gas chain valve, the combination gas valve is a lot more convenient to use. This is because all of its components come in one package.
- Easy to Maintain – Because it comes in one package, it is easier to maintain.
- – Although the combination gas valve is a better version of the gas chain valve, it has been replaced with the solenoid valve.
Signs Your Gas Valve is Bad
A faulty gas valve is one of the most common reasons your furnace will stop supplying heat. It is essential to secure the efficiency of your furnace, primarily as the cold weather draws near. And the gas valve is the first component that ensures your furnace supplies you with heat at all.
In addition to that, here are a few you should watch out for:
- The furnace stops supplying enough or no heat at all to your house.
- When your gas valve goes bad, the furnace might shut down completely. So, if your furnace shuts down unexpectedly, it could be a sign of a faulty gas valve.
- Strange noises. The furnace sometimes makes funny noises whenever one of the major components goes bad.
- There could be other issues you might not notice as some problems might go beyond the gas valve. Therefore, it is best to contact a trained technician for a proper inspection.
What Would Make a Gas Valve Fail?
As you know, a faulty gas valve could be the problem if your furnace is not producing heat. There are more than one reasons why your furnace’s gas valve could go bad, here they are:
- The valve may have worn out or broken as a result of basement seepage or submersion.
- Another possibility is one of the electronic gas ignition components is bad.
- Also, a flaw in the safety circuit might be the cause.
- If your furnace has a standing pilot light, a worn thermocouple might be the cause of the gas valve going bad.
How Much Does it Cost to Repair a Gas Valve?
The real question here should be, “Is it worth it to repair a gas valve.” In some cases, you can repair a gas valve, depending on the problem and how serious it is. But, it is not the best advice considering the fact that it’s not the most cost-effective option. Repairing a gas valve can be just as expensive as replacing the whole thing entirely.
How to Know When to Replace Your Gas Valve
You need to be aware of the warning signals that your gas valve is failing.
- Weak Voltage – Normally, the gas valve receives 24volts from the furnace transformer, this allows it to open and close. If after testing you don’t get 24volts, and there is no internal clicking, that is an indication that your gas valve does not open and close.
- Faulty Coils and Wires – Always examine the wires and coils that are attached to your valves. Frayed and worn-out connections can affect the opening and closing of your furnace’s gas valve. If this is the case of your furnace’s gas valve then it has to be replaced.
- Leakages – Because of how dangerous combustion gases are, leakages should not be taken lightly. Check pressure levels to see whether the valve isn’t operating because of wrong settings. Unclog your burner orifices and ducting, since a lack of flow might also be the source of the problem. You can test for leaks with an electronic gas sniffer.
How to Install and Replace Your Gas Valve
Uninstalling the Old Gas Valve
- The first thing you must do before replacing your gas valve is to turn off off the furnace’s power switch. To avoid getting shocked by the electricity or blowing up a component in the furnace.
- Then shut off the main gas supply.
- Next, unscrew the nuts securing the front panel and remove it.
- Using pipe wrenches, separate the gas pipe union. One wrench for grading the pipe, and the other for unscrewing the nut.
- Now remove the gas inlet from the gas valve. Gently unscrew the pipe connected to the gas valve with a wrench. When you do this, make sure to grab the other end of the pipe connected to the gas valve with another wrench. This will stabilize the gas valve while you unscrew the other end, so it doesn’t break.
- Disconnect the wires attached to the gas valve. Disconnect the grounding wire as well.
- Now, disconnect the screws securing the gas manifold and the valve to the burner’s housing. You can do this with a screwdriver.
- Remove the old gas valve assembly and disconnect the old valve using a wrench.
It’s Time to Install the New One!
- Before installing the new valve, remove the inlet and outlet plugs. Then apply some sealant to the threads of the manifold. They enable easy access to the gas valve.
- Now, secure your new valve and thread the manifold into the outlet port of the gas valve. First, screw the valve gently with your hand to ensure balance, then tighten with the wrench.
- Re-position the manifold the same way it was. Make sure it aligns appropriately with the burner tubes. Then replace the screws and tighten.
- Reconnect the grounding wires and the wires connected to the valve. Make sure you connect them to the appropriate terminals on the new valve.
- Secure the wires with a zip tire for a clear view.
- Turn on the gas valve switch.
- Apply a sealant on the threads of the pipe. Secure it into the new gas valve assembly and tighten it with a wrench.
- Secure the gas pipes, reconnect them, and tighten them with a wrench.
- Next, turn the gas supply back on.
- Now check the gas pipes connection and make sure there are no leaks.
- Once there are no leaks, replace and secure the cover panel, then tighten.
- Finally, turn on the power supply. Your furnace should be ready for use now.
Troubleshooting a Furnace Gas Valve
Before troubleshooting a gas furnace valve, it is essential you first understand the sequence of operation of the furnace. Knowing the steps will help you trace the faults and how to fix them. Pay close attention to the following sequence before troubleshooting.
- Step one: Once you turn on your furnace, the thermostat signals a call for heat.
- Step two: Then the inducer motor ignites.
- Step three: After the inducer motor has been turned on, the pressure switch should prove the inducer motor is operating correctly.
- Step four: Then the igniter activates, energizing the gas valve.
- Step five: The flames flow across the burners.
- Step six: The flames sensors prove that all the burners are lit.
- Step seven: Finally, the furnace blower forces air into your homes through the ducts.
The sequence above happens in three stages; even if one step does not perform right, the rest of the components will still do what they are supposed to do. Once you master all phases of the furnace’s operation, it will be easier to trace problems in your furnace when things go wrong.
First, turn on your furnace, and pay attention to the sequence of operation. If any of the steps mentioned above skips, then you can trace the problem from there. Since we are troubleshooting a gas valve, the gas valve would be the faulty one. When your gas valve goes wrong, the problem will either be electrical or mechanical.
First, check for loose connections. One of the wires connected to the gas valve may be loose or worn out. If you find any faults with the wires, replace them and reconnect your valve if you can. If you cannot, please contact a trained professional.
In a typical case, before the gas valve can begin its operation, it must receive 24 volts of current from the transformer. Furthermore, before condemning the gas valve, first, check for volts readings. You can do it with an ohmmeter.
The ohmmeter has one large button and two lead terminals. Turn the button to “V,” which is for voltage. Then grab the leads and place them on the connection of the coil at the gas valve.
Check the reading for 24 volts. If the meter does not show 24 volts, then it might not be the valve’s fault. However, if the meter reads 24 volts, the valve is bad, and you need to replace it.
If your test confirms that the problem with your valve is not electrical, then it is likely mechanical. In this case, you need to replace the gas valve if your can (see instructions above in article), and if you cannot, please get in touch with a trained professional.
Question: What Does a Furnace Gas Valve Do?
Answer: A gas valve is the component that allows gas to flow around your furnace. It does this by opening and closing.
Question: How Often Should a Furnace’s Gas Valve Be Replaced?
Answer: Normally, a gas valve should last up to 15years or more. However, it can break down even before that. Every gas valve has manufactural date of production stamped behind it.
Question: How Long Does a Gas Valve Last?
Answer: With proper maintenance, a gas valve can last up to 15years.
Question: How Much Does it Cost to Replace a Furnace’s Gas Valve?
Answer: Replacing a furnace’s gas valve costs ranges from $200 to $600.
Question: Can a Furnace’s Gas Valve Be Replaced?
Answer: In some cases yes, a furnace’s gas valve can be repaired, depending on what the problem is. But, repairing a gas valve is not the best choice, this is because it is just as expensive as replacing the whole thing.
Question: How Many Volts Do You Need to Open a Gas Valve?
Answer: For most gas valves, you only need 24volts, either a/c or d/c current.
Question: How Do I Know When I Gas Valve is Bad?
Answer: If you have 24 volts going from the board to the gas valve terminals but don’t hear the internal valve’s clicking noise, you may have a faulty gas valve. To make sure, disconnect the leads and check the gas valve. You do you have 24 volts then the problem may not be the gas valve.
The gas valve is just as important as the furnace itself. Without the gas valve, there will be no gas flow and without gas, the furnace cannot produce heat. Learning and understanding how the gas valve work, what it does in your furnace and how to take care of it, will help maintain the life of your furnace.
With a proper care, a gas valve can last up to 10 to 15years. This article covers everything you need to know about the furnace’s gas valve including repair and maintenance.