How To Check Gas Pressure On Furnace

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Your gas furnace may have stopped working, but that doesn't mean you have to telephone call for a professional person repair but even so. If y'all turned your furnace off for the summer or take noticed it isn't heating up properly, it could be due to inadequate gas pressure. You tin can use the gas valve inside the furnace to tweak the pressure setting. Well-nigh furnaces accept a unmarried valve, but two-stage furnaces will accept carve up high and low-pressure valves. Information technology's a uncomplicated aligning that can be done inside a few minutes, merely contact a licensed heating and cooling specialist if you observe gas leaks or other serious problems.

1. 1

   Unscrew the forepart access panel on the furnace. On many furnaces, the access panel will be held in place by a serial of iv screws. If your furnace is like this, you lot will run into the screws near the panel's corners. Rotate them all counterclockwise with a Phillips screwdriver. Once they are off, the console can be lifted off of the furnace.^[1]

   • If the panel doesn't have screws, only lift it upward to detach it from the furnace.
   • The front panel may have vents or instructional stickers on it that make it more than recognizable. The other panels aren't removable.

2. 2

   Locate the metal box containing the valves on the gas pipe. The gas pipe is usually along the lower part of the access point. If y'all're unsure where it is, follow the piping from the wall of your abode to where information technology enters the furnace. You will likewise spot a big, metallic box in the center. Look for a large, round tower with a metal screw sticking out of its top. The screw is what you use to command the gas pressure level. Most furnaces accept only one of these valves, but some furnaces have 2 of them together.^[2]

   • The control box containing the valve may accept some other components on it, such as a labeled pilot light command knob.
   • On a two-stage furnace, one valve is for low pressure level and the other is for high pressure level. The high-force per unit area valve doesn't activate until the furnace gets hot enough. The verbal temperature varies between furnaces.

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3. 3

   Relight the pilot light if the furnace isn't already on. Unless the furnace has gas flowing through information technology, you won't be able to monitor its pressure. You may have turned the furnace off during the summertime, for instance, or it close off on its own due to low gas force per unit area. Start by checking the fuse box or excursion console in your home to brand sure the electricity is on. Once information technology is on, locate the pilot lite switch near the gas valve and plow it off. Await five minutes earlier activating the pilot calorie-free and so relighting it with a long stem lighter.^[3]

   • For more data on how to turn on your furnace, check the stickers the manufacturer placed virtually the front end access panel. These stickers volition accept instructions specific to your furnace model.
   • The pilot light is along the top role of the furnace. Follow the tube leading from the control box to observe it.
   • Take your time when relighting a furnace. If the gas isn't given fourth dimension to fully dissipate, reigniting the pilot low-cal could cause a fire.

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1. i

   Twist the outlet port cap counterclockwise past hand to remove information technology. Check underneath the valve on the side of the box. It will accept a pigsty covered past a metal cap. For many furnaces, you tin can remove the cap by rotating it counterclockwise. Fix the cap aside to reveal the open port. This port allows you to monitor the gas pressure while adjusting the valve.^[iv]

   • Some gas valves require you to have a hex key. If you lot need ane, fit a ⁱⁱⁱ⁄₃₂  in (0.24 cm) hex fundamental into the cap and turn it counterclockwise to remove it.

2. 2

   Hook a clear connecting hose to the barbed tip of a manometer. A manometer is a handheld device that measures gas force per unit area. Go 1 that measures in inches of h2o column (WC). The manometer should also come up with a clear connecting hose. If it doesn't, purchase a manometer hose separately. Push the hose onto the metal affront on top of the manometer to set up it up.^[v]

   • Dual-port manometers accept a pair of barbs. If yours is similar this, utilize a double-concluded hose that can connect to both barbs at once.
   • You can buy manometers online and at many hardware stores.

3. iii

   Plug the manometer into the outlet port with a tube adapter. A manometer tube adapter is a plug that connects the testing tube to the furnace. To install a new adapter, push the circular stop into the manometer hose until it stays in place. Plug the barbed end of the adapter into the furnace'due south outlet, and so turn it clockwise by hand to lock it in identify.^[6]

   • If the manometer tube doesn't come with an adapter, purchase one separately. Most furnaces work well with a ¹⁄₈  in (0.32 cm) adapter. On some furnaces, you can push the tube onto the outlet port without using an adapter.
   • If you have a two-stage gas furnace, start with the taller valve, which is responsible for the loftier-pressure setting. Each valve will have its own outlet, so make sure yous have the manometer hooked upwards to the right one!

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1. 1

   Check the safe force per unit area setting listed almost the valve. Look all over the furnace for some stickers placed by the manufacturer. They contain a lot of valuable data, including the correct pressure settings for the gas valve. The force per unit area listings are often on the access panel itself, but they tin also be on one of the other exterior panels.^[7]

   • If you take a two-stage furnace, await for split up high and low-pressure listings.
   • If you aren't able to find the force per unit area setting used by your furnace, contact a professional. Using the wrong setting can cause the furnace to overheat, and so avoid the take a chance of having to contend with costly repairs.

2. two

   Plough on the manometer to get an initial pressure level reading. Press the power button on the manometer's front to turn it on. It will low-cal up right away equally information technology detects the gas pressure. Set the manometer in a spot where it is out your mode but all the same readable. Many manometers take a magnet on the back that you can use to hang up the device nearby while you lot work.

   • If the manometer doesn't light up, make sure it is well-connected to the valve. Check that the gas and pilot lite are on as well.
   • If the furnace seems to exist working, remove the battery embrace on the back stop of the manometer. They ordinarily run on a unmarried 9-volt battery. Replace it to meet if the battery is dead.

3. iii

   Ready the high pressure to iii.5 inches of h2o column (WC) for natural gas. Note that the optimal setting varies betwixt furnaces, so consult the manufacturer'south instructions before making any adjustments. When y'all're ready, go dorsum to the screw on the meridian or side of the gas valve. Use a flathead screwdriver to turn the screw. Rotating information technology clockwise raises the gas pressure, while rotating it counterclockwise reduces the pressure. If your furnace only has one pressure valve, you lot tin remove the manometer and cover the outlet port.^[8]

   • For a propane furnace, the valve has to be set to 11 inches of WC or a similar number.
   • Continue an eye on the manometer, since its display volition change as yous adjust the valve.
   • Tune the gas pressure level gradually. For safety, tune information technology to the pressure rating recommended by the manufacturer.

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1. i

   Locate the shorter valve if your furnace has 1. Discover the metal box forth the center part of the gas pipe. The taller valve is the 1 responsible for the high-force per unit area setting on a two-phase furnace. Wait for a noticeably shorter valve next to information technology. Besides being a little shorter, the low-force per unit area valve will expect most identical to the loftier pressure one. Set the high pressure level get-go, and so go on the manometer attached to the outlet port.^[nine]

   • Low-force per unit area valves oft take a much shorter screw than high-pressure valves do, so you lot can use that to tell them autonomously.
   • Not all furnaces take both valves. If you don't take a two-stage furnace, yous won't have to worry near setting high and low pressures. The manufacturer'south directions will only accept a single recommended pressure listed also.

2. ii

   Turn the heat down low using the thermostat. Plough information technology down every bit low as it can go. At a depression-temperature setting, your furnace doesn't need to create as much heat, and then the high-pressure valve shuts off. Lookout man the manometer's display, since it will alter as it detects the lower pressure level. You lot will also exist able to hear the furnace get quieter equally the temperature drops.^[x]

   • You won't take to disconnect the manometer at all. Leave it continued to the outlet valve near the pipe.

3. three

   Adjust the low-pressure level valve to 1.6 WC for natural gas. Bank check the pressure level setting recommended past the manufacturer. When yous have it, slip a flathead screwdriver into the valve. Turn it clockwise to enhance the pressure and counterclockwise to lower it. In one case it'due south at the recommended setting, your furnace will exist in working order again.^[eleven]

   • The proper pressure can vary from furnace to furnace. For instance, on a propane furnace, it volition be around 4.0 inches of WC.
   • Mixing upwardly the high and depression-force per unit area settings is easy, so double-check the instructional sticker near the access panel. Make certain you're using the "high fire" number for the loftier-force per unit area valve and the "low fire" number for the low-pressure level valve.

4. 4

   Remove the manometer and close up the furnace. Unscrew the adapter from the pressure valve outlet, and so return the outlet plug. Hang the front admission panel on the furnace next. If information technology had screws, put them back and turn them clockwise to secure it in identify.

   • If you are sure the gas pressure is correct but are yet experiencing problems with the furnace, contact a heating and cooling specialist.

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• If the furnace won't turn on at all, check the control knob on the gas pipage leading from the wall of your dwelling to your furnace. If information technology has been turned perpendicular to the pipe, rotate information technology to allow gas to accomplish the furnace.^[12]

• Go on an eye on the thermostat to see if it is performance. Make sure the brandish matches the heat given off by the furnace.^[thirteen]

• If you are unable to adjust the valve or notice annihilation wrong with your furnace, contact a heating and cooling technician in your expanse. Permit them make sure the furnace is safe to use.

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• Approach an active furnace advisedly to avert burns or electric shock. Avoid touching exposed electric wires, and operate gas valves with caution.

• If your furnace is off, reactivating the airplane pilot lite tin lead to a fire. Make certain you accept drained all gas out of the line before reigniting the pilot calorie-free.^[xiv]

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Things You lot'll Need

• Phillips screwdriver
• Flathead screwdriver
• Manometer
• Manometer hose
• ¹⁄_viii  in (0.32 cm) MPT adapter
• Long stem lighter (optional)

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