Now that the weather is getting cooler, there may be times that you need to turn on the heat, even though we live in a warm climate. If your gas furnace becomes faulty, one of the first things you notice is that it has started to shut off abruptly.
In this article, you’re going to learn a lot, starting from facts about the furnace gas valve to the equipment and tools you’ll need to check the furnace gas valve and how to check the furnace gas valve with a multimeter.
What are furnace gas valves and how it work?
The solenoid, an electrical component that receives signals from the thermostat control, is attached to the furnace gas valves. Response to variations in building temperature, causes the gas valve to widen or constrict in front of the pilot light.
For instance, the gas valve opens to turn on the furnace and create extra heat if the temperature in your home drops below the thermostat setting, which is typically 68 degrees Fahrenheit. A different signal prompts the gas valve to close when the building achieves the specified temperature. You may verify that the valve operates by using a multimeter test.
The inner furnace has many moving parts, the valve is one of the most important. Similar to any other valve, it functions by opening and closing to let gas flow to the burners and pilot light.
Equipment and tools needed
- High-quality Clamp meter and Multimeter combo kit
- Jumper wire set
- A socket set
How to test a furnace gas valve with multimeter
It is strongly advised that you check out the potential of a gas supply issue before you begin checking your gas valve. The best course of action is to test any other gas-powered appliances in your house. For instance, you still have gas if the stove functions. If it doesn’t, though, you might be dealing with a totally different problem that needs the help of a specialist.
Here’s how to test a furnace gas valve.
Step 1- Start the furnace
Firstly, turn on the furnace and notify the control board to turn on the heat. Setting the thermostat to a higher temperature is the simplest way to do this. This will assist in starting the draught motor and the hot surface igniter. At this stage, the valve should be turned on if everything else is in working condition.
Step 2: Check to see if the gas valve is receiving power
Two wires should typically be connected to the valves. Anyone is a viable option. At this point, it makes no difference. Using your clamp meter, clamp the wire of your choice. As you turn on the furnace, pay close attention to what is being shown on the meter. If it reads 0, try clamping the other wire. If for a brief period, there is a little amp pulled off up to 0.2 amps, you have the right wire. You may use this to check if your valve is receiving electricity or not. You should be aware that this just eliminates an electrical problem as one of the possible causes and does not ensure the condition of the valve.
Step 3. Verify the voltage
It is a good idea to check the voltage as well to confirm the power situation. Put the probes on the connection between the gas valve and the wires using the multimeter, set to Volts AC (VAC). Call for heat, and the voltage should reach around 24 volts in 3 seconds. Power can be ruled out as a potential source of the issue if you find that the gas meter is indeed receiving this much electricity but that no gas is flowing.
Step 4: Turn on the power supply after turning it off.
Since you have established that power is not the issue, you can now turn off the system’s power supply to reduce the possibility of an unintentional discharge or electrical shock. The next step is to swap out the gas valve’s low-voltage cables for two jumper wires. Please note that the duration of the next check should not exceed three seconds.
There are two sets of wires on the transformer: line voltage in black and white and 24 volts in red and brown. From the gas valve to the connections, connect the jumper wires in the proper order. Close the door, reconnect the power, and turn it on for around three seconds. Pay close attention to the gas flow. If the gas doesn’t run, the gas valve is obviously broken.
Step 5: Close the control box after resetting it
You must have realized by this point that your problems are related to either the gas valve itself, the power source, or yet unidentified issues. It is advised to turn off the equipment right away and get expert assistance. Clover Services can assist you in resolving any problems you are having with your gas furnace.
Read Also: How To Test A Pressure Transducer With A Multimeter?
Conclusion
Learning how to check a furnace’s gas valve is not a bad idea. Before beginning, it is suggested to have a good image of the wire setup and the gas valve. When it’s time to put cables back where they belong, you may use this as a useful guide.
FAQs
How to Test the Gas Valve in the Furnace for 24 Volts
Set the voltage on your electrical multimeter. Place the multimeter leads on each of the two wires if there are two wires leading to the gas valve. This is what? You should have 24 volts if the inducer motor is operating and the thermostat is calling for heat.
How can the voltage on a furnace gas valve be tested?
Connecting the two low-voltage wires from the gas valve to a 24-volt coil (like a contactor coil) and attempting to start the furnace are useful ways to determine if the voltage is correct or whether the valve coil has failed. The ignition control is working properly and has not failed if the contactor pulls in.
What controls the gas valve on a furnace?
Electromagnets are used to activate the furnace gas valve. Gas for the pilot light is supplied via the primary valve, sometimes referred to as the safety valve. Gas can flow to the burner trays through the second valve, also referred to as the main valve. The power that maintains the safety valve open is produced by the thermocouple (or thermopile)
Reference https://superheatandair.com/gas-furnace-problems-heres-how-to-check-the-gas-valve/