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How to Drain a Water Heater

WARNING! TO AVOID ELECTRICAL SHOCK...Before beginning this procedure, turn off the electricity coming into the unit before beginning to drain it. This will also keep the heating elements inside the tank from being damaged.

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Your water heater should have a water cutoff valve on the feeder line coming into the heater and a drain valve near the bottom. Attach a garden hose to the drain valve on the unit. Route the hose so that the water will flow in a downhill direction from the water heater. With a pump or syphon, you may be able to go over some obstacles on the way to a suitable place for draining the water. Turn the water off going into the water heater. Turn on a hot water faucet somewhere nearby. This will provide a vent necessary to let the water flow from the tank.

Open the valve at the bottom of the tank and let the water flow out through the hose to the drainage area. If no water comes out, make sure that the hose is not kinked or running uphill at some point. If the hose is going over an obstacle of some type, start a syphon with the hose to get the water running. The draining end of the hose will still need to be lower than the water in the tank. If you intend to completely drain the entire device, the hose will need to be lower than the valve it is attached to.

If you cannot get the water to flow through the hose, turn off the drain valve and disconnect the hose. Open the drain valve a little to see if water comes out. If nothing comes out when you open the valve, you will need to seek another source for the problem. If it seems have a reasonable flow, reconnect the hose and reroute it in a more downward direction. Make sure that you have an open faucet to let air into the tank so it will drain. A way to test for an air inlet is to open the popoff valve at the top of the tank. If the water still does not begin to flow, it means either the tank is clogged or the popoff valve is malfunctioning.

To check for a clog, take a stiff wire like a clothes hanger and push it up into the tank through the drain valve. If sediment is the problem, you will encounter resistance. In older tanks, you can have up to half of the tank filled with sediment. Repeat the process with the clothes hanger and you should be able to loosen up enough of the sediment in a few minutes to let the water drain. You may need to repeat the procedure a few times.

With electric water heaters, when you finally have it drained, pull the elements and see how deep the sediment is. If the tank is half filled with sediment, the most economical thing to do would be to replace the water heater. Under those conditions, a forty gallon tank is probably only producing about twenty–five gallons of hot water. Let the water heater drain until no more water comes out. Close the valve and disconnect the hose. Do not turn on the electric until the water heater is either repaired or replaced.






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