If your house is to be vacated during cold weather and the heating system turned off, follow this procedure carefully or contact your plumber for assistance.
Shut off the water supply at the main shutoff valve at the street. Then beginning with those on the top floor, open all faucets and leave them open. When water stops running from these faucets, open the cap on the main shut off valve in the basement and drain the remaining water into a pail or tub. Remember that this cap must be closed after the faucets have run dry, or the house water supply will flow from this valve and flood the basement.
Remove all water in the traps under all sinks, toilets, and bathtubs by opening the clean-out plugs at the bottom of traps and draining them into a pail. If no plugs are provided, use a force pump or other method to siphon the water out. Sponge all the water out of the toilet bowl. Clean out all water in the flush tank.
Fill all traps with a non-freezing solution such as mineral oil, windshield washing fluid or RV type anti-freeze.
Drain all hot water tanks. Most water tanks are equipped with a vented tube at the top, which lets air in and allows the water to drain out the faucet at the bottom. Make sure all horizontal pipes drain properly. Air pressure will get rid of trapped water in these pipes, but occasionally the piping may have to be disconnected and drained. To be safe have your plumber check your entire plumbing system.
If your house is heated by hot water or steam, drain the heating pipes and boiler before leaving. Burners and pilots should be completely out and the main water supply turned off at the basement wall or street. Draw off the water for the boiler by opening the draw-off valve at the lowest point in the system.
Open the water supply valve to the boiler so no water will be trapped above it. If you have a hot water system, begin with the highest radiators and open the air valve on each as fast as the water lowers. Every radiator valve must be opened on the one-inch pipe system to release condensation.
Note: When you return home, refill the system before lighting the hot water heater or the boilers.
Caution: Keeping the temperature in a house below 60 degrees Fahrenheit is not good for the house.