August 4, 2009
To flush your water heater, follow the steps listed below. Please read them completely before performing this procedure.
CAUTION: Flushing a water heater can be dangerous. Be careful and keep children and pets away to prevent scalding during the procedure.
A typical water heater tank holds 30 to 100 gallons of water. Therefore, it is important to select the best location for drainage that presents the fewest undesirable consequences.
Drainage systems made of PVC are not designed to handle temperatures in excess of 140F. Therefore, draining directly into your drainage system can cause serious and costly problems.
Draining a water heater into the yard will likely harm the grass or any vegetation due to the water’s extreme heat.
Draining a water heater onto a driveway or street will likely stain the concrete with rust.
Tools / Equipment Needed :
- Eye protection
- Protective gloves
- Breaker box lock out kit (for electric water heaters without a readily accessible cut-off switch)
- Quality garden hose capable of withstanding high water temperatures
- #2 Flathead Screwdriver
(1) Turn off the power source to the heater. If the heater is equipped with an electrical anode rod, switch off its electricity.
On gas heaters, turn the gas control valve and the gas stop off.
On electric heaters without a readily accessible electrical cut-off switch (electrical switch is in the same room or closet as the heater), turn the relative circuit breaker off and lock the circuit box.
On electric water heaters equipped with a readily accessible cut off switch, place the switch in the off position.
(2) Shut the water off at the cut-off valve on the cold side inlet of the water heater.
Caution : Your water heater may have been installed with a gate valve at the inlet. Gate valves use a round wheel for the handle and require several turns to shut the water off. Gate valves have proven to be unreliable. If so equipped, it may be best to shut the water off at the house’s main cut-off or at the meter. For this application, AAA AUGER recommends that the gate valve be replaced with a ball valve. This will require advanced skill and may be better left to a professional.
(3) Connect the garden hose to the drain valve on the heater.
(4) Terminate the opposite end of the hose to a safe discharge location. The hose should be placed with as few curves as possible.
(5) In the closest bathroom, turn on the hot water completely at the bath tub faucet.
(6) Open the drain valve. If the water flows steadily, continue to step 7.
Note : Mineral clusters may become lodged in the valve preventing the water to drain properly. Should this occur, it may be possible to dislodge or break up the clusters with a screwdriver. Be extra careful to avoid damaging the drain valve.
Servicing the drain valve will require the removal of the garden hose. Before removing the hose, turn off the drain valve and seek other means to best contain or divert the water.
AAA AUGER recommends letting the water in the tank cool before servicing the drain valve to prevent scalding!
Although uncommon, the drain valve may be compacted with mineral deposits. This is a good indicator that the water heater should be replaced and any further efforts to flush the heater may be futile.
(7) Engage the T & P valve (move the small handle upward to the vertical position). Should the handle not maintain its vertical position, the T & P valve must be replaced before re-engaging the water heater.
Engaging the T & P valve will allow the pressure to escape from the tank. If the tank stays pressurized, not only will the water drain slowly, but a vacuum will form and cause undue stress to the tank.
More importantly, the T & P (temperature and pressure) valve is the water heater’s primary safety apparatus. Should the temperature and/or pressure within the tank exceed safe limits, the T & P valve is designed to release the pressure to avoid an explosion.
(8) After the water heater has been drained, close the drain valve, disengage the T & P valve and turn off the bath tub faucet.
(9) Turn the water on and allow the tank to fill. Once filled, again, open the drain valve (with the water supply “on”).
(10) With the water running, allow the water heater to drain until the water is clear and free of debris.
(11) Turn the drain valve off.
(12) Before powering the water heater, verify that the tank has filled completely (listen for water flow at the cold inlet).
(13) In the closest bathroom, turn on the hot water to the bath tub faucet. This will bleed the water system of air and flush residual debris. When bleeding water lines, bathtub faucets are preferred over lavatory or kitchen faucets because they do not typically have aerators (strainers at the end of the faucet) which can become clogged with debris.
It may be necessary to bleed the other faucets as well. Should the water stream be erratic or not uniform, the aerators will need to be unscrewed and cleaned.
(14) Once the system has been bled of air, the water heater is ready to be powered. If equipped with an electrical anode rod, restore its electricity.
Note: Severely neglected systems may require multiple and/or more frequent flushing.
Flushing the Water Heater / Final notes
Some professionals recommend that detergents or acid based products be used to help break down the mineral deposits. AAA AUGER does not recommend this process. Although with proper flushing, the potential for health risk is greatly reduced, the detergents can cause the tank and the components within to deteriorate at a faster rate. Furthermore, we believe that any tank that may require such a process is already in need of replacement.
Heaters with Circulating Systems
Due to the various designs of circulating systems, AAA AUGER advises that the manufacturer’s directions be followed when flushing the heater. If the instructions are not easily located, please provide us with the brand, model and/or serial number of the pump and we will attempt to locate them for you.