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Manage air supply when draining water from heater

QuestionI have an electric water heater and a couple of years ago I had to put in a new bottom element. I had a heck of a time getting the tank to drain. Any suggestions on how to make it drain faster—or at all? It has been suggested that I put a water softener on the pipe that goes to the water heater. I have heard of magnetic ones, but where do you get them? Thanks.

AnswerWhen you drain your water heater, it helps to open the hot side of a household faucet (preferably one nearest the tank) after shutting off the tank's water supply line. This lets air into the tank to help it drain properly.

You could also remove the flexible copper tubing connected to the top of the water heater from the cold side using an open-end adjustable wrench. This will relieve the water pressure in the supply line and tank, which also allows air to enter the tank to help it drain easier. However, before draining the tank be sure to turn off the power to the tank!

It also sounds like your tank contained a lot of sediment that partially blocked the drain valve. In the future, try draining as much as you can from the tank, then refill it halfway and drain the tank again. You may have to do this a few times to help break up the sediment.

If this procedure doesn't work, remove the drain valve completely in order to clear any blockage in the drain hole or in front of it. However, before attempting this, create an air lock on the tank. You can accomplish this by not opening the hot side of the household faucet; in fact, make sure that no faucets anywhere in the home are open and turn off the cold water supply line to the tank.

Proceed by removing the drain valve (some water may come out) and check to see if the opening is blocked completely or partially. Next, take a 3/8-inch soft copper pipe roughly 24 inches long and smash one end down with a hammer to form a chisel-like end.

Poke it into the sediment to break it up to clear the opening. Don't be afraid to penetrate the sediment; the idea is to break it up as much as possible so it can drain out. Once the opening is cleared, reinstall the valve and open the household faucet and the drain valve. If it drains normally, great. If not, then the drain opening is again plugged so you'll have to repeat the process until it drains normally. This will be a messy project!

To avoid future sediment buildup, perform regular maintenance on the tank by draining a couple of buckets of water every other month.

The magnetic device you refer to is a magnetic water conditioner and has been manufactured in the US since 1985. These units were first introduced as traditional magnets that simply clamped onto the main water pipe. Now they sport cool colors and cases, and new models are installed inline. There are many similar devices on the market under different trade names, selling from $39.95 up to $559.00 for pipes sized from 1/2" to 3/4". To find them online, type magnetic water conditioner into your favorite search engine and start plowing through the long list of results.

At least two magnetic water conditioners are needed on the incoming water supply between the water meter and the water heater spaced about 1" to 1 1/2" apart. Then install two booster units on the water heater: one on the cold water supply entering the tank and one on the hot side as it exits the tank. The magnets won't work if you have galvanized steel or iron plumbing pipes; however, you can replace the pipe with a minimum of 18" of new pipe (CPVC, copper, or approved indoor plumbing material) on either side of the magnetic units. Note that a permit may be required.

If you replace a section of the water line with any non-metallic water supply line, then the home's electrical path to ground will be interrupted. This is easily remedied by installing a jumper ground over the replaced areas. For 200-amp service, the jumper should be #4 copper wire. Connect one end of the ground wire with a grounding clamp to one side of the metallic water pipe and carry the other end of the wire over the length of the non-metallic water supply line. Finally, connect it back to the metallic water pipe with a grounding clamp.

While we are on the subject, you'll need two "dielectric unions" to make the connection if copper is used to replace the section of galvanized piping. If water conditions aren't right, the mismatch of these two dissimilar metals, i.e., the connection, will fail in a few years through electrolytic corrosion. These unions have one side made of brass and the other of galvanized iron. The nut that draws them together, however is isolated by a plastic washer that keeps the metals from contacting each other. Unfortunately, these dielectric unions will break the path to ground, as discussed above. Again, place a jumper ground on the pipes before and after the new section in order to bond the pipes together.

How does the magnetic system work? Basically, water contains dissolved mineral salts, mainly calcium and magnesium. When water enters the tank, these minerals precipitate out and build up as sediment, a natural crystallization process accelerated by heating the water. However, as water moves in the earth, it creates a naturally equal ionic (electric) charge between the minerals and the water. In theory, as the water passes through pipes outfitted with magnetic water conditioners, the water becomes magnetically charged. Electrically the water takes on a greater ionic charge than the minerals, which creates a natural magnetic attraction between the two. The magnetization then attracts and locks the dissolved minerals into the water creating healthy and cost-free descaling.

I've seen my plumber use these devices over the years, but I can't tell you whether or not they work as I've never used them. Personally, I would rather invest in a proven system like a water softener than purchase a magnetic system that I'm not sure about.

Copyright © 2004, 2006, & 2008 LAF/C.R.S., Inc. All rights reserved.
Question answered by Leon A. Frechette.

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