De-Winterizing Guide: How to Restore Water Supply Piping, Drain Piping, Water Pumps, Tanks, Heaters to Use InspectAPedia® -
How to find, thaw, and repair frozen water pipes or heating pipes
How to de-winterize a building and restore the plumbing & heating systems to service
When where, why, and how to check for & fix water supply and drain leaks
How to return "shut down" water softeners or other water treatment equipment to operation
Questions & answers about returning a winterized building back into service
This article explains how to de-winterize a building, including turning the water supply back on and getting heat, plumbing fixtures and other systems working.
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We also discuss what problems to look for when de-winterizing a building. The articles at this website will answer most questions about freeze protection for piping and other building plumbing and heating system components: how to winterize a building to avoid frozen pipes, and how to thaw frozen water supply & drain piping, wells, & water tanks.
Tips for Finding and Thawing Frozen Water or Heating Pipes
"Frozen pipes" does not mean that the entire length of plumbing or heating lines has become frozen. More often pipes freeze at one or more "cold spots" such as those we've discussed above.
Our photo shows building piping running through a poorly insulated area behind a shower. The combination of lack of building insulation, lack of pipe insulation, and the inability of building heat to enter this chase-way resulted in a frozen water pipe where we're shining our flashlight.
The steps below discuss how to find just where piping has frozen and how then to thaw it out safely.
We've used simple touch, by hand, feeling pipes for changed in the pipe temperature, or infra-red scanners to scan along piping to look for a drop in pipe temperature that may mark a frozen pipe location. If the heating pipes are frozen, often a section of the heating baseboard will be hot (hot water rising into the piping by convection if not forced by the circulator pump).
Some methods we've seen used to thaw frozen pipes, in our preferred order include:
Turn up building heat to thaw frozen piping: this often works, but is the slowest, if safest, way to thaw frozen pipes. The risk is that you haven't found and warmed the frozen piping soon enough to prevent a burst water pipe.
Use a hair dryer blower to warm frozen piping. A hair dryer is less likely to start a fire than other methods listed below, but nonetheless be watchful for sparks or debris and have a fire extinguisher handy. Just plug the hair dryer into a safe (GFCI) outlet and blow it back and forth along the suspected frozen pipe section.
When water begins to flow you may hear some gurgling if it's a heating line, or if the frozen line was a water supply pipe the faucet or fixture that was not operating may begin to flow as soon as the pipe is just partly un-frozen, when a passage for water is opened enough to let water flow. Once this occurs, you can simply run more water to warm and free the remaining ice.
Use a heating tape to thaw a frozen section of piping. This step may take a little longer than the hair-dryer approach, but it has the advantage that you can properly install and leave the heating tape in place until you've done a better job of warming the area where the problem pipe runs.
Use of a propane torch to thaw frozen piping: this is a little faster than using a hair dryer blower, and also more dangerous. Open nearby faucets to let any steam or water vapor escape as the pipe thaws; work from the un-frozen pipe section back towards where you suspect the freeze-up has occurred; this will let you see water or steam begin to exit the pipe when you get to the ice.
Do not direct the torch too close to soldered joints or you are likely to de-solder the joint, causing the pipe sections to separate, leading to a more serious leak than ever.
Move the torch back and forth along the frozen pipe rapidly enough to avoid super-heating any small pipe section and thus reducing the chances of de-soldering a joint or causing unsafe pressure in the middle of a section of frozen piping.
Use an electric welder to thaw frozen pipes: some plumbers and others hook up an electric welder to plumbing lines to thaw frozen pipes. To us this seems dangerous and we wouldn't try it.
Listen and look for burst pipe leaks immediately: your frozen pipe may also have burst or separated at a solder connection. So as soon as you hear water flowing, search the building thoroughly to be double sure that a pipe has not burst. If you find that your thawed pipe is leaking in one or more places:
Turn off the building water supply unless you can immediately find a shutoff valve that will just close water supply to the leaking pipe section
Clean up the spilled water so you don't generate a mold contamination problem
How to Repair Frozen Pipes that Burst or Leak
Although we may have been careful to follow all of the best practices in winterizing a building, it is still possible that a pipe has frozen and burst during cold weather.
If a hot water heating pipe has frozen or a steam condensate heating pipe has frozen you won't see the leak until the building warms up but you may have trouble getting heat in some areas.
If a water supply pipe has frozen you will see the leak as soon as the building warms up and the frozen pipe thaws, unless water has been turned off.
If a drain pipe has frozen you'll notice it as the drain will be blocked. Worse will be the discovery of unsanitary water leaking when the piping thaws. Here are some tips for making repairs when these problems occur. A frozen fixture trap will be a smaller local leak that you should discover quickly by inspecting each fixture. The exception which occurs commonly is a frozen bath shower trap in a bathroom over an unheated garage. Such traps or other plumbing leaks may drain into the garage ceiling where they cause more damage and take a bit longer to discover.
Find & repair the any frozen, leaky pipe breaks, cut out and replace that section of piping as follows:
A temporary leaky pipe repair can be made using a clamp-on pipe patch; you'll need to buy a clamp-on patch of the proper diameter for your pipe.
A pinhole pipe leak (unlikely to occur in the case of freezing pipes) may be temporarily repaired by screwing in a small diameter sheet metal screw combined with a rubber washer. We've seen people try to repair a water supply pipe leak by wrapping it with electrical tape or duct tape: most likely you can slow but not stop a leak by this method.
How to cut out or remove and replace a broken frozen or leaky pipe section.
Replacing leaky threaded galvanized iron pipes: If the pipe is threaded galvanized steel it may be possible to cut the pipe in order to unscrew the damaged section in two parts, followed by installing two shorter threaded replacement sections combined with a union or coupling.
Replacing leaky copper pipes: If the broken leaky pipe is copper piping it can be cut with a pipe cutter or in close quarters with a hacksaw blade, followed by cleaning the exposed pipe ends, removing any water in the piping, and soldering in the new section. Be careful not to set nearby building materials on fire. Wrap any nearby soldered pipe joints with a wet rag to reduce the chance that during your solder repair you accidentally de-solder nearby joints. It's possible to use copper pipe compression fittings as a means to connect cut copper pipe ends where soldering cannot be used.
Replacing leaky plastic pipes: is usually easy, using new plastic pipe sections of the same material an the proper glue and pipe couplings. Just be sure to clean all of the pipe ends and fittings before applying the glue. Any grease or debris on the exposed plastic pipe ends can prevent the glue from bonding.
Lead water supply piping in a building should be removed and replaced entirely.
Drain pipe repairs of copper or plastic drain lines can be made using the same procedures above. If your building has cast iron drain piping that has broken you'll need the services of a professional to cut and install replacement sections of cast iron; rubber Fernco™ type couplings can be used to patch in plastic drain pipes onto a cast iron or even copper drain line if necessary.
Turn the water supply back on and check again for leaks
Critical Steps in Returning a Winterized Building to Service
Although we may have been careful to follow all of the best practices in winterizing a building, it is still possible that a pipe has frozen and burst during cold weather. So the procedure of turning heat and water supply back on in a building needs to include some careful and frequent checks for leaks or unsafe (heating system) conditions. Never ever simply turn on water, heat, or even electricity in a building that has been shut-down without remaining to monitor for unsafe conditions, fire, smoke, improper heating system operation, or the presence of leaks.
Turning on the Heating System After a Building Has Been Winterized
We prefer to get heat working again in the building if it has been shut down, before starting other plumbing work.
But look at the heating equipment before even thinking of turning it back on. If your furnace has been flooded as this one, it is possible that the system is unsafe and should not be turned back on. Before turning a heating system back on we need to:
Know that the heating chimney and flue are safe and un-damaged
Know that the heating distribution system is un-damaged (such as a visual check for frozen, burst hot water heating pipes.) This inspection may be only an initial step since further checks and inspections will be in order as soon as the system is on and warming up.
Have heating fuel and electricity
Heating service call recommended: Depending on what was done to turn off the heat, (such as draining a boiler), a service call from your heating service technician will be needed. The service should include not only restoring the boiler or furnace to good operating condition, but also checking that the chimney and venting have not become blocked or unsafe (raccoons may build a home in an un-used chimney).
If the heating system was a steam or hot water boiler, check the boiler carefully for leaks when it is restored to service.
Particularly some models of cast iron heating boilers may include boiler sections which loosen when the boiler spends months in a "cold" state, leading to boiler section leaks when the heater is filled and returned to service.
Restoring the Building Drain System after a Building Has Been Winterized or "freeze-proofed"
Remember to replace any plumbing traps that were removed from sinks, tubs, showers, etc. before trying out a fixture by turning on its faucets.
Then when you are ready to turn on the water supply, remember to run enough water into each fixture to fill the trap, then check the trap for leaks.
If your traps corroded, or if the trap arrangement is improper like this crazy collection of double-S-traps under a sink (photo at left), this is a good time to toss the old parts and have a plumber install a new trap that drains properly.
After you have turned on water supply, try each fixture by running a gallon or less of water into it. Then turn off the water and check the fixture trap for leaks.
When you're confident that you've restored the fixture trap without leaks, run water longer to test the building drain piping for blockage or leaks.
Stop, look, and listen for leaks. Before leaving the building that has been de-winterized, turn on one or more fixtures at a time, leave water running for a few minutes while you walk through the building looking and listening for evidence of a drain leak. Check for drain leaks before leaving the building. Of course if you detect a leak in the drain system turn the water supply off immediately and remove any spills before starting the leak repair.
Staged Steps in Turning on Water Supply System to Minimize Water Leak Damage in buildings
Here we recommend that you follow a staged step by step approach to turning on water in a building where the water supply has been shut down over a winter or during a period of absence. The staged approach lets us check each building area and fixture one by one, minimizing the chances of extensive water damage even if a leak has occurred while the building was unattended.
Even for buildings located in areas not subject to freezing and burst pipes, a staged water turn-on approach is useful. A pipe may have been damaged or cut by building activities, a trap may have corroded through, or other plumbing damage may be present even if no freezing conditions occurred.
Step by Step Details of the staged water-on procedure can be read at Turning on Water.
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"New Electric Heat Tapes Help Prevent Fires," US Consumer Product Safety Commission (CPSC) #00936
"Freezeproof Your House," Mike McClintock, Rodale's New Shelter, p. 30, October 1985 (approximate date)
"How to Winterize Your Pipes," Mike McClintock, Homeowners How-To Magazine, p. 59-62, Nov-Dec 1979.
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Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair
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