When it comes to installing a gas line for an 80,000 BTU furnace, it is important to know the right size of the gas line.
Choosing the wrong size can lead to a variety of problems, including insufficient gas supply, which can cause the furnace to malfunction or even shut down.
In this article, we will discuss the process of determining what size of gas line for an 80,000 BTU furnace, the various types of gas lines available, and the installation process.
What Size Gas Line For 80,000 BTU Furnace?
For an 80,000 BTU furnace, a 1/2″ diameter gas line is typically sufficient when the line is less than 40 feet long. If the distance is longer, or additional appliances are connected, a 3/4″ line may be necessary to ensure adequate gas supply and optimal furnace performance.
80,000 BTU Furnace Gas Line Size Chart:
| Nominal Pipe Size Copper(in.) | Pipe Length(ft.) 10 | Pipe Length(ft.) 20 | Pipe Length(ft.) 40 | Pipe Length(ft.) 80 |
|---|---|---|---|---|
| 1/4 (3/8) | 35 | 25 | 17 | 12 |
| 3/8 (1/2) | 75 | 50 | 35 | 25 |
| 1/2 (5/8) | 150 | 105 | 70 | 50 |
| 5/8 (3/4) | 265 | 180 | 125 | 85 |
| 3/4 (7/8) | 380 | 260 | 180 | 120 |
| 1 (1 1/8) | 805 | 555 | 380 | 260 |
| 1 1/4 (1 3/8) | 1450 | 995 | 685 | 470 |
Different Types of Gas Lines Compatible with 80,000 BTU Furnaces
Flexible Gas Lines
Flexible gas lines are easy to install and adjust. They can bend around corners and obstacles, making them a good choice for complex installations. However, they can be more expensive than other options and may not be as durable.
Black Iron Gas Lines
Black iron gas lines are very durable and can withstand high pressure, making them a reliable choice for 80,000 BTU furnaces. They are also resistant to corrosion.
However, they are rigid and require more effort to install. They also need more fittings and connections, which can increase the risk of leaks if not properly installed.
Corrugated Stainless Steel Tubing (CSST)
CSST is flexible like flexible gas lines but has the durability of black iron gas lines. It’s easy to install and requires fewer fittings and connections, reducing the risk of leaks. However, it’s the most expensive option and requires special tools for installation.
How To Determine Gas Line Size For 80,000 BTU Furnace
It would be best if you considered a few factors when determining the appropriate gas line size for an 80,000 BTU furnace.
Follow the below steps to ensure you get the right size gas line.
1. Know the BTU rating of your furnace. The BTU, or British Thermal Unit, is a unit of measurement for energy.
One BTU is the amount of energy needed to raise one pound of water by one degree Fahrenheit. So, an 80,000 BTU furnace needs 80,000 BTU of power to operate.
2. Know the pressure of your gas line. The pressure is measured in psi, or pounds per square inch.
As we mentioned above, most home gas lines have a pressure of between 5 and 10 psi.
3. Use the information above to determine the appropriate gas line size for your furnace. For an 80,000 BTU furnace, you will need a 3/4-inch gas line.
This is because the BTU rating of your furnace divided by the pressure of your gas line should be between 240 and 360. And 3/4-inch is the closest size to 360.
So, there you have it. Now you know what size gas line you need for your 80,000 BTU furnace.
Appropriate Gas Line Size For 80,000 BTU Furnace
Now that you know the BTU and pressure of your furnace, you can determine the appropriate gas line size.
The appropriate gas line size for an 80,000 BTU furnace is a 3/4-inch line.
This is because the BTU rating of your furnace divided by the pressure of your gas line should be between 240 and 360. And 3/4-inch is the closest size to 360.
If you have a 5 psi gas line, your BTU rating should be no more than 1,800. If you have a 10 psi gas line, your BTU rating should be no more than 3,600.
So, an 80,000 BTU furnace would not be able to operate on a 5 psi gas line but would be just fine on a 10 psi gas line.
Now that you know what size gas line you need for your 80,000 BTU furnace, you can be sure that your furnace will have enough gas to operate correctly.
How To Install A Gas Line For An 80,000 BTU Furnace
Now that you know what size gas line you need for your furnace, you may wonder how to install it.
Here are a few tips on how to install a gas line for an 80,000 BTU furnace.
- Ensure the power is off to the furnace before you begin.
- If running a new line, use a 3/4-inch black steel pipe. For natural gas lines, the pipe should be scheduled 40. If you use a propane furnace, the pipe should be designed 80.
- Use fittings that are approved for gas lines. Do not use improvised fittings, as they could leak.
- Make sure all connections are tight. Use two wrenches to tighten the fittings so that one twist holds the fitting while the other wrench tightens the connection.
- Once the line is installed, turn on the gas and test for leaks. Use soapy water and a brush to check all connections for bubbles. If you see any bubbles, that means there is a gas leak. Shut off the gas immediately and fix the leak.
By following these steps, you can be sure that your gas line is installed correctly and safely.
Besides the 3/4-inch black steel pipe, you will need fittings and approved connectors for gas lines.
Make sure all connections are tight so there are no leaks. And finally, test for leaks before you turn on the gas to the furnace.
FAQs
How Far Can You Run 1/2 Inch Gas Line?
The maximum distance you can run a 1/2-inch gas line is 40 feet. If you need to run the line further than that, you will need to upgrade to a larger size pipe.
However, the most common pipe size for home gas lines is 3/4-inch. So, if your furnace is more than 40 feet from the gas line, you will most likely need to upgrade to a 3/4-inch pipe.
Can I Use A PVC Pipe For A Gas Line?
PVC pipes are adaptable and can be used for both natural gas lines and water supply. Because of the high pressure of natural gas, it is not recommended to use a PVC pipe for a gas line.
The best type of pipe to use for a gas line is a black steel pipe. Remember, if you use a propane furnace, the tube should be scheduled 80.
Can I Use A Flexible Gas Line?
Yes, you can use a flexible gas line. Flexible gas lines are perfectly safe as long as they’re installed correctly. Besides, it would help if you only used it for short runs, such as from the stove to the wall.
For longer runs, you will need to use a rigid pipe. As a result, you can use a flexible gas line for your furnace if it’s no more than 3 feet long.
Can I Use Copper Pipes for Gas Lines?
Yes, you can use copper pipes for gas lines, but they must be type K or L and should not be used in areas where the gas contains high sulfur content, as it can corrode the copper.
Does the Length of the Gas Line Affect Furnace Performance?
Yes, the length of the gas line affects furnace performance; longer runs require larger diameter pipes to ensure adequate gas pressure and volume.
Final Thoughts
Now you know what size gas line you need for your 80,000 BTU furnace.
Remember that the most important thing is to follow all safety precautions when working with gas lines.
So, turn off the power to the furnace before you begin, use the appropriate fittings, and ensure all connections are tight.
Never use improvised fittings, as they could leak.
