Testing Furnace Gas Control Valve

Step 1 check for coil burnout.

Testing furnace gas control valve. Testing gas pressure at the valves is often the first thing hvac technicians do when they are called in to check on faulty furnaces. Check to see if you re getting 24 vac at the terminals on the gas valve. Locate the gas valve. If solenoid valves are malfunctioning dangerous pressure might build up and cause damage.

Turn off the furnace at the wall control. The following steps will show you how to troubleshoot gas control valve solenoids. Turn off the gas supply valve to your appliance to test whether your valve is capable of shutting down properly. Wait for the unit to cool if it has been in use.

There are four possible reasons for solenoid valves malfunction. If the appliance is a boiler or furnace it ll use 24 vac to operate the main valve. How to check the furnace gas valve with a multimeter step 1. The difference is the standing pilot gas furnace always has a pilot light on.

Coil burnout failure to open failure to close or solenoid valve noise. Some gas valves cannot be checked with an ohmm. Take out the bolts in the service panel on the side of the furnace using a nut driver. There should not be a flame up there if the valve is working correctly.

If you do get voltage then i would be testing for gas pressure before the gas valve and the manifold pressure when the gas valve has voltage. Adjust pilot flame as necessary to make sure the thermocouple is getting enough heat. Locate the hot surface igniter and look for a spark or glow there. Set the thermostat or the device s controller slightly above the current room temperature.

Even though these systems are generally built to last gas furnace valves are the parts more likely to need replacement over the life of the furnace. Turn off the gas feed line valve to the dryer. The ignitor will be 120 volts the gas valve is most likely 24 see if your transformer shows voltage on the secondary terminals. This valve is usually found in the wall line leading to the dryer and is shut off by turning the handle perpendicular to the gas line.

Most gas dryers have pullout snap panels. I will be checking various gas valves to see if you can check the continuity of the solenoid with an ohmmeter. Everything that applies to the electronic ignition sequence of operation by the way of the safety circuit must be proven before the gas furnace will allow the gas valve to fire the main burners to provide heat. Standard solenoid valves are used for pneumatic gases.

If so and the boiler or furnace isn t firing up then you need a new gas valve. Locate the front lower access panel to the appliance.