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AGE of WATER HEATERS
ALTERNATIVE HOT WATER SOURCES
ANODES & DIP TUBES on WATER HEATERS
ANTI SCALD VALVES
APPLIANCE DIAGNOSIS & REPAIR
APPLIANCE EFFICIENCY RATINGS
AQUASTAT CONTROL Functions
BACKDRAFTING HEATING EQUIPMENT
BACKFLOW PREVENTER, HEATER WATER FEEDER
CARBON MONOXIDE - CO
CHECK VALVES, WATER SUPPLY
CLOGGED SUPPLY PIPING
CROSS CONNECTIONS, PLUMBING
DEBRIS in WATER SUPPLY, Water Heater
DRAIN a WATER HEATER TANK
ELECTRIC WATER HEATERS
FLOODED WATER HEATER REPAIR
FREEZE-PROOF A BUILDING
GALVANIC SCALE & METAL CORROSION
GAS BURNER Flame & Noise Defects
GAS FIRED WATER HEATERS
GAS PIPING, VALVES, CONTROLS
HEATING COST SAVINGS METHODS
HOT WATER SUPPLY
HOT WATER IMPROVEMENTS
HOT WATER DELIVERY SPEED UP
HOT WATER EFFICIENCY IMPROVEMENT
HOT WATER PRESSURE EXPANSION RATE
HOT WATER PRESSURE LOSS
HOT WATER PROBLEM DIAGNOSIS
HOT WATER QUANTITY IMPROVEMENT
HYDROGEN SULFIDE GAS
INDIRECT FIRED WATER HEATERS
MANUALS & PARTS GUIDES - HVAC
MIXING / ANTI-SCALD VALVES
NO HEAT - NO HOT WATER: HEATER DIAGNOSIS
NOISE, WATER HEATER
ODORS IN WATER
PIPING IN buildings, Clogs Leaks Types
RELIEF VALVE LEAKS
RELIEF VALVES - Water Heaters
SCALE REMOVAL, WATER HEATERS
SEWER GAS ODORS
SOLAR HOT WATER HEATERS
TANKLESS WATER HEATERS
THERMAL EXPANSION of HOT WATER
THERMOSTATS, WATER HEATER
TIMERS for ELECTRIC WATER HEATERS
WATER HEATER ALTERNATIVES
WATER HEATER ANODES, DIP TUBES
WATER HEATER AIR INLET
WATER HEATER DEBRIS FLUSH
WATER HEATER DRAIN PROCEDURE
WATER HEATER EFFICIENCY
WATER HEATER FLUSH PROCEDURE
WATER HEATER NOISES
WATER HEATER PROBLEM DIAGNOSIS
WATER HEATER PROPERTIES
WATER HEATER SCALE
WATER HEATER SAFETY
WATER HEATERS for HOME HEATING USE?
WATER ODORS, CAUSE CURE
WATER PIPES, Clogs Leaks Types
WATER PRESSURE TOO HIGH: DANGERS
WATER PRESSURE LOSS DIAGNOSIS & REPAIR
WATER QUANTITY IMPROVEMENT
WATER SOFTENERS & CONDITIONERS
WINTERIZE A BUILDING
Here we explain just how to drain the water out of a water heater tank. This step is a necessary first step for several water heater maintenance and repair procedures such as water heater flush-out, water heater scale removal, or replacement of the water heater pressure-temperature relief valve.
This series of water heater maintenance and repair articles describes how to inspect, operate, diagnose, and repair electric hot water heaters.
The articles at this website will answer most questions about water heaters as well as many other building plumbing system inspection or defect topics. This page contains links to in-depth articles on inspecting, testing, and repairing problems residential hot water heaters of all types, including their parts, controls, and alternative sources for hot water as well as tips for improving hot water temperature, hot water pressure, and hot water quantity.
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Question: Can I Drain My Water Heater Myself?
We have a gas water heater. I’m a rather handy man. Would it be possible for me to flush it myself? What is a typical cost for this kind of service? - K.S., Seattle
Reply: Sure, if you're handy and careful, it's not difficult and not many tools are needed. But
Watch out: it's easy if nothing goes wrong (we list some things that can go wrong here and at WATER HEATER DEBRIS FLUSH. And there are a few safety things to get right: avoiding being scalded, avoiding damaging a pressure/temperature relief valve, and avoiding flooding the home because of a snafu.
More details about draining and cleaning or de-scaling a hot water tank, including the removal of mineral or lime deposits and silt, are provided at WATER HEATER NOISES where we describe water heater flushout and water heater scale removal.
If plastic water piping is installed, such as polybutylene water supply piping, it should be at least 18" from the water heater.
Water heater vacuum relief valves are required at water heaters in some communities, to protect against collapse of the water storage tank and to prevent backup of hot water into the cold water piping should cold water pressure drop. Here is Carson Dunlop's sketch of a vacuum relief valve.
What Goes Wrong When Draining the Water Heater Tank?
Watch out for these common problems that occur when you try to just drain a hot water heater tank:
Don't forget to turn off water coming into the water heater tank or you'll certainly never get it drained.
The water heater tank drain valve may be defective, may fail to open, or may fail to shut off, or worse, may break so that water comes blasting into the room where the heater is located. If this happens you will have to be able to turn off cold water coming into the water heater, and even so, water that is in the water heater tank and in building piping above the heater will drain backwards through the heater and onto the floor. Don't force any parts, especially parts on a plastic water heater drain valve.
Water heater tank drain valves are a pretty standard plumbing part. If your valve is worn or damaged, or if you just want to be extra safe, buy a replacement valve at a lumber or hardware supplier before starting your project. Most valves are standard 3/4" male pipe thread. You'll also need teflon tape or teflon pipe dope for the pipe threads.
The water heater cold water supply valve may not shut off: especially as that valve may not have been used for quite some time. Or you may not be able to turn the valve. Do not force the valve - you may break it. Sometimes we can loosen a recalcitrant water shutoff valve by a combination of a little squirt of WD-40 or a spray used by mechanics to free frozen nuts and bolts. Don't get these chemicals inside the water heater.
If your water heater supply valve won't turn off fully and is just dripping into the hot water tank, you can live with that during a water heater drain and repair project. If the valve won't turn off at all, you may have to turn off another supply valve upstream from the water tank, or possibly you'll need to turn off water supply to the whole building before starting your project.
If you run into trouble you won't want to have to leave the whole building water supply shut down, so having a few spare parts on hand to be able to close off the water heater itself (relief valve, tank drain valve) may be necessary.
The water heater relief valve may leak: often we use the test lever to allow air into the water heater tank during draining, as that will speed up the water heater tank drain process. But lifting the test lever can allow a bit of debris or even a damaged relief valve seat washer to flow out. At WATER HEATER DEBRIS FLUSH we discuss dealing with this problem.
Where should the water heater draining garden hose drain-to? If you are routing a water heater drain hose to an indoor floor drain, be sure that drain is not clogged before beginning the project. Try pouring a bucket of water into the drain. If you are routing the water heater drain hose to outdoors, the water leaving the water heater tank should empty far enough from the building that it won't leak back into the structure through the foundation wall. At WATER HEATER DEBRIS FLUSH we discuss dealing with this problem.
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