A drain valve is important for the maintenance of a water heater. It removes mineral sediments and debris from the bottom of the water heater tank. Sediments can accumulate and cause all sorts of problems in the water heater. Sediments can affect the performance and efficiency of a water heater. They can hike up your energy bills. They can cause fluctuations in your hot water temperature. They are corrosive. They can eat up your tank and eventually cause your heater to fail.
In this article, we will learn how to repair a drain valve, and, if it cannot be repaired, how to replace it.
How to Repair a Drain Valve
If water is not draining out of your water heater, your drain valve is probably clogged. To unclog it, you can do two things:
- Use a garden hose to remove blockage: Connect a garden hose to your drain valve and blow into it so that the air can dislodge the scales clogging the valve.
- Back flush the drain valve: Connect a garden hose to your drain valve and blow into it so that the air can dislodge the scales clogging the valve. If blowing into the garden hose didn't work, you can blast water from a faucet into the drain valve. This should dislodge any scales clogging the drain valve. For Backflush, in addition to a garden hose, you will need a washing machine hose. Connect one end of the washing machine hose to a threaded faucet, and connect its other end to the garden hose. Open the faucet for 10 seconds to blast water into the tank. This should push the sediments into the tank, freeing the valve. Disconnect the washing machine hose and resume draining the tank. If the valve gets clogged again you might need to backflush again, and even more times if required.
If you have had a problem with your draining valve clogging or draining slowly, you might want to replace your valve with a much wider brass drain valve. A larger diameter valve will prevent any future blockages. You will also need to replace your drain valve if it is broken, or it is leaking.
What You Will Need
- Teflon tape
- Flat blade screwdriver
- Washing machine hose
How to Replace a Drain Valve
You will also need to replace your drain valve if it is broken, or it is leaking. If you have had a problem with your draining valve clogging or draining slowly, you might want to replace your valve with a much wider brass drain valve. A larger diameter valve will prevent any future blockages.
Step 1: Turn Off the Power Supply
For gas water heaters, turn off the gas supply valve by turning the valve handle perpendicular to the pipe. For electric water heaters, turn off the breaker at the breaker panel.
Step 2: Turn Off the Cold Water Supply
At the top of the tank, there should be two pipelines. One of them has a valve. Turn the valve so that it is perpendicular to the pipelines.
Step 3: Open the Hot Water Faucet to Let the Air in and Empty the Tank
You need to empty the tank before replacing the drain valve. Turn on the hot water at several faucets to empty the hot water. If you don't hear any water flowing or air being sucked into the system then you might have a backflow preventer valve installed somewhere into your plumbing. This prevents air from entering into your system. As a result, opening a faucet is not enough to let the air into the system. You will need to open the pressure relief valve. Relief valve is always located at the top of the tank. Lift the valve to open it, and your will water flowing out of the hot water faucet.
Step 4: Remove the Drain Valve
First, place a towel under the drain to catch any water that might spill while replacing the drain. Use an adjustable wrench to loosen the drain valve, and then unscrew the valve.
What if you have a broken valve or a plastic valve that broke while you were trying to unscrew it? Well, you will need a saw to cut off the broken drain valve. After that, saw off the pieces of plastic inside the tank, stuck to the tank's metal threads. Do not cut the metal threads. Use a plier to pull the pieces of the plastic loose, and clean the metal threads with a wire brush. Your tank is ready for a new brass drain valve.
Step 5: Install the Drain Valve
Wrap some plumber’s tape to the brass valve threads in a clockwise direction. Apply 3 to 4 wraps. Screw the valve into the tank with your hand until it is hand-tight, and then use the adjustable wrench to tighten it further.
Congratulations, you have successfully replaced your drain valve. Now, you simply need to restart your water heater and your job is done here.
Step 6: Restart the Tank
Before you turn on the water supply, check whether the new drain valve is closed. The drain valve handle should be perpendicular to the tank. Open a hot water faucet inside your house to let the air out of the water heater tank.
Now open the cold water supply. You should hear water filling the tank. Once it reaches a certain point, water will start flowing out of the hot water faucet. Close the faucet once you get a smooth stream of water. This will tell you that the tank is full and the air has been removed.
Turn on the power supply. For an electric water heater, turn on the breaker from the breaker panel. For gas, turn on the gas supply and relight the pilot light. If you don't know how to relight a pilot light, check out my article "How to Light a Water Heater Pilot Light."