The recent floods in Texas and elsewhere have brought to light the need to inspect your furnace as soon as the water recedes. Furnaces are typically placed in the lowest part of the home that is most susceptible to flooding waters, and most or all it can get swamped. There are some parts that are not designed to get wet at all, and if they do, you should replace them before you start using the furnace again when it gets cold outside. One such part is the gas valve. If the gas valve gets wet, the parts inside it will corrode, and you could end up having a dangerous gas leak when you start using the furance again. Here is how an average homeowner can replace the gas valve on their own after a flood.
Turn Off Utilities
You should turn off the electric and gas going to the furnace before you start working. Turn the electricity off at the switch and at the circuit breaker for extra protection. The gas shutoff valve is located on the gas line going to the furnace. The gas valve shutoff will have a straight handle on it. Turn the handle so it is perpendicular to the gas line.
Remove Gas Valve
Follow the gas line into the furnace. The gas line connects directly to the gas valve inside the furnace. You need to unscrew the nut holding the gas line to the valve with a crescent wrench. Unscrew the nut and disconnect the gas line from the valve.
There are two wires connected to the gas valve. Remove the wires from the terminals on the valve.
The gas valve is also attached to a bracket on the furnace. Remove the screws to the bracket and remove the gas valve and the gas pipe leading to the burners. This will all come out as one unit.
The gas valve is screwed into the gas pipe. Take a pipe wrench and place it on the gas pipe and twist the gas valve counter-clockwise to unscrew it from the pipe. If the valve is on too tight, use a large pipe wrench to put over it to give you some leverage and twist. Don't worry about damaging the valve since you're going to recycle or throw it anyway.
Install New Gas Valve
Make sure you buy a gas valve specifically made for the make and model of your furnace. Put plumbing tape on the gas pipe threads and screw the valve back on. Reconnect the gas valve and bracket to the front of the furnace and reconnect the external gas line to the valve (again, use plumbing tape on the threads). Twist the valve until it tightens and is in the upright position. Plug the wires back into the terminals and turn the gas and electricity back.
For more information, contact Economy Air Systems Inc or a similar company.