How to replace a water heater drain valve
If the drain valve is leaking it is faulty and will need replacing.
Before the valve can be replaced you must drain the water from the heater tank.
Before draining the tank you must switch off the water heater electricity supply, locate the breaker and switch it off. If you have a gas heater set the temperature control to the lowest setting and the control knob to pilot.
Turn off the water supply to the heater.
Be aware that the water being drained may be very hot.
Connect one end of a length of garden hose to the drain valve, put the other end into the nearest floor drain or take it outside the building.
Open the temperature and pressure relief valve located on the top or on the side of the heater, this will allow air into the heater so that the water can drain.
Open the drain valve by turning the handle fully anti-clockwise, if it does not have a handle and is the plastic type, take hold of the fixture and turn it fully anti-clockwise.
Allow the heater tank to drain, you may notice sediment in the water being drained, this is normal once all the water has drained it is worth flushing the heater to remove any remaining sediment.
To flush the water heater, close the drain valve, turn on the water supply and allow a few gallons of water to run into the heater, open the drain valve and observe the water draining, when it runs clear, turn off the water supply.
Remove the hose pipe from the drain valve. Using a wrench remove the valve, a little more water may drain so have a sponge or some rags ready to soak up the water.
Fit the new valve ensuring that you wrap some Teflon tape around the thread to prevent water leaking, ensure the new valve is in the closed position.
Open the nearest hot water faucet and turn on the water supply
When the water is running smoothly close the temperature and pressure relief valve and then turn off the faucet.
Allow the water heater to fill with water.
Check that there are no leaks around the valve.
If an electric heater, switch the power back on.
If a gas heater, set the control knob to the on position and set the temperature control to the normal setting and if necessary re-light the pilot.