How To Drain the Main Plumbing System
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How To Drain the Main Plumbing System

How to drain the main plumbing system to perform major plumbing repairs. You can use a sewer rod, drain auger for basement water backups, and sewage backup.

There are several reasons for draining the main plumbing system. One is to perform major plumbing repairs. Another is to prevent the pipes from freezing if the furnace malfunctions while the house is left untended for long periods in cold weather. Older homes have air chambers that prevent noise and vibration when a faucet is closed. If the air is displaced from these chambers, a hammering noise will develop in the pipes. To cure it, drain the main plumbing system.

First, turn off the water supply at the main shutoff valve. Then shut off the furnace and the current or gas to the water heater. Next, flush all toilets and open every faucet in the house. If your home is heated by a hot-water system, open all radiator valves (if the radiators have individual valves). Remove the air-escape valve from one or more radiators (baseboard or other types) on the highest floor of the house. Then drain the furnace and water heater.

After the heating system is empty, open the drain valve on the main supply line. If no such spigot exists, determine where the lowest point in your system is and disconnect a fitting there to allow any remaining water to run out of the pipes. If your water supply is from a well, drain both the above-ground pump lines and the tank. Pump lines inside of deep wells seldom freeze, but check with your pump service man to be safe. Be sue to switch the pump off and drain it completely. By that point, all water should have drained out except that in toilet bowls and drain traps. Empty the toilet bowls with a siphon, or by bailing and sponging. Then, pour a mixture of antifreeze and water into the trap of every sink, wash basin, shower stall, and bathtub. Prepare this mixture for the lowest temperature expected in your area, according to the directions on the can.

Unclogging the Main Drain.

If water is backed up in lower floor household fixtures, the main drain in the basement is probably blocked. To locate the clog, begin at the cleanout hole nearest the affected fixtures. Place a bucket beneath the cleanout and partially loosen the plug. If water drips from the plug, the stoppage is between that cleanout and the sewer. If water does not drip, check the next plug up the line.

Once the dripping cleanout has been found, loosen its plug gradually and let all the standing water drain into a bucket. Run a drain auger into the pipe until you reach the blockage, then work the auger back and forth vigorously while turning it with the handle to break up the obstruction. If you have no auger, and the clog is near, you may be able to clear the line with a makeshift device, such as a straightened-out-coat hanger.

If none of your tools will reach the clog, rent a sewer rod from a tool rental agency. Feed it in as you would any auger, but do not rotate it. (This job is better left to professionals.)

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Comments (4)

How to drain the main vein!! Good article. ; )

Well written and informative article. Voted up.

A great DIY article.... which I hope I will never have to tacke lol!

Nice article. Thanks for sharing.