How to test the oven pressure switch with a multimeter
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Pressure switches are critical to system operation. They check that the gas is coming out of the oven before starting it and send a signal to the oven control panel to make sure the inductor motor is working. However, the oven pressure switch can also fail or get stuck open, which can have underlying problems that are best diagnosed through testing.
So, in this guide, let me show you more about how to test the furnace pressure switch with a multimeter.
6 steps to test the oven pressure switch
Step 1: Disconnect the switch wires. Disconnect the wires from the switch terminals to disconnect the wires associated with the pressure switch. (1)
Step 2: Set the multimeter to continuity or ohm setting (usually denoted by the symbol Ω). Make sure you're tracking single ohms and not megaohms.
Step 3: Turn the pressure switch. You will see different terminals. Take the multimeter wires and touch one of them on each switch terminal in those terminals.
Step 4: After that, the oven is turned on.
Step 5: The draft regulator motor will then fire and blow air out of the vent, creating a vacuum that retracts the diaphragm and closes the switch.
Step 6: Use a multimeter to check for changes and for the switch to close.
If the multimeter reading is 0 or close to 0, then you are testing for a closed switch, indicating that it is working well and showing continuity. However, if you see infinity or a higher multimeter reading, the switch remains open, meaning no change in continuity, and it's a bad pressure switch. Therefore, you must replace the switch immediately to fix the problem.
Other features to look out for
Before deciding to replace an inductor motor or switch, you must first take into account other potential issues, including:
- Kink in the hose
- pipe clogged
- Anything else that prevents the inductor motor from blowing air out of the vent.
These factors can make it difficult for the gas oven pressure switch to work properly. So, before you ultimately decide to replace the pressure switch, make sure you have considered these questions.
If none of the above and you have exhausted all other options for troubleshooting and checking for defects, it's time to replace the pressure switch.
F.A.Q.
What does a pressure switch do?
Furnace pressure switches are safety devices located next to the draft inductor motor of a forced air gas furnace. Its function is to prevent the oven from starting unless there is adequate air pressure for ventilation. It is designed to detect the negative pressure generated by the draft motor when the furnace is started and shut down the furnace if the air pressure is insufficient to remove the exhaust gases.
In addition, a diaphragm is attached to the switch. The diaphragm is then attached to a switch that indicates whether it is open or closed. When a vacuum is present, the diaphragm expands and closes the switch. However, the switch remains open if there is no vacuum. In this case, the oven is switched off. (2)
What causes the pressure switch to fail?
1. The fan motor stopped working.
2. The air intake and combustion air vent is closed.
3. Assembly leakage
4. Clogged condensate drain
5. The pressure switch has an electrical problem, such as loose wires.
6. Suction tube is low
7. Blockage in the chimney
What to do if the furnace pressure switch fails?
In the event of a switch failure, there are several recovery options:
1. If the pressure switch stops working, you will not be able to hear the opening of the valve. If there is sound, the pressure switch is in good condition.
2. Turn off the oven is also an option. Then check if the fan is making noise. Also, if the engine is running slowly or you notice something else, the problem is with the engine and should be replaced, not the switch.
3. Make sure the switch hose is secure. A loose switch hose can be tightened to fix the problem, but a hole in the line may need to be sealed. Alternatively, you can remove the broken section and reconnect the hose. Before replacing, make sure that the case is in order. Once the hose has been repaired, the switch will eventually work properly.
If you find that none of these problems exist, you may have a faulty pressure switch. To find out if this is the problem, you will need a multimeter for the testing process.
Take a look at some of our articles below.
- How to test the power window switch with a multimeter
- How to test a light switch with a multimeter
- How to test a capacitor with a multimeter
Recommendations
(1) pressure - https://www.britannica.com/science/pressure
(2) diaphragm – https://www.healthline.com/human-body-maps/diaphragm
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