How to Winterize a Sprinkler System
Shut off the water supply., Attach a compressor to the mainline., Activate the furthest station., Close the backflow isolation valves and open the compressor valve., Activate the remaining stations., Shut off the compressor., Remove excess water...
Step-by-Step Guide
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Step 1: Shut off the water supply.
Turn the water supply off at the main water valve to prevent more water from entering the system.
After completing this step, all you need to do is drain the water already inside the system.
The shut off valve for your sprinkler system should be located in an area that is unable to freeze over.
Usually, it will be located inside the home, in a basement, garage, or utility closet.
In some cases, a stop and waste valve will be located underground.
It can be as deep as 5 feet (1.5 m) down, so you may need a long key to turn it. -
Step 2: Attach a compressor to the mainline.
Hook up a small compressor to the mainline with a quick coupler, hose bib, or other type of connection, as determined by the connection located after the backflow device.
You will need a compressor with a CFM (cubic foot per minute) rating of 80 to 100 for any mainline with a diameter of 2 inches (5 cm) or less.Rent the equipment at an equipment rental yard.
Note that a small shop compressor will not have enough air to do the job right.
If you have the original layout for your sprinkler system and it shows the GPM (gallons per minute) running through each sprinkler head, divide the total GPM of each section or zone by
7.5.
This calculation will give you the exact CFM you need to blow the system out.Do not fully charge the holding tank before releasing the pressurized air into the compensator as a way of compensating for less CFM.
Only perform this method if you find a compressor with the right amount of CFM.
Make sure that the compressor valve is in the closed position as you attach the hose to the fitting.
Both valves on the backflow preventer should be closed, as well.
Do not blow compressed air through the backflow device.
Take extra precaution when using highly compressed air.
Compressed air can lead to injury and damage, especially if used improperly. , This station should be on the controller that is in the zone furthest away from the compressor, or the sprinklers at the highest elevation away from the compressor. , Once the backflow valves are closed, slowly open the valve on the compressor to slowly allow air to fill the sprinkler system.
The blow out pressure should always remain below the maximum operating pressure of the lowest pressure rated component in your system.
It should also never exceed 80 PSI for PVC pipe systems, or 50 psi for flexible black polyethylene pipe systems. , Work your way along the system, slowly activating each station or zone.
Activate the stations furthest from the compressor first before working your way to the closest station.
You should activate each station until no additional water can be seen draining from the sprinkler heads.
This can take about two minutes, if not longer, per station.
Consider using two or three short cycles per station rather than one long cycle.
If it seems to take longer than two minutes to drain the water for each station, you may need to deactivate the stations early and repeat the procedure two or three times.
As soon as a station is dry, you should stop blowing air through the pipe.
Blowing compressed air through a dry pipe can create friction and heat, which could damage the pipe.
Never run the compressor without having at least one station valve open.
You should only run air through one zone or section at a time.
If you attempt to do more than that, the excess velocity of the air can add friction and heat to the pipe and fittings, which could cause them to melt. , As soon as the systems have all been dried, disconnect the compressor from the system.
Delaying can cause damage to your pipes.
Open the valves on the system to release any excess air pressure. , If the sprinkler system has a backflow device with ball valves, open and close the isolation valves on the device a few times to force any trapped water to escape.
Leave these isolation valves open at a 45 degree angle and open the test cocks on the system. -
Step 3: Activate the furthest station.
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Step 4: Close the backflow isolation valves and open the compressor valve.
-
Step 5: Activate the remaining stations.
-
Step 6: Shut off the compressor.
-
Step 7: Remove excess water from the system.
Detailed Guide
Turn the water supply off at the main water valve to prevent more water from entering the system.
After completing this step, all you need to do is drain the water already inside the system.
The shut off valve for your sprinkler system should be located in an area that is unable to freeze over.
Usually, it will be located inside the home, in a basement, garage, or utility closet.
In some cases, a stop and waste valve will be located underground.
It can be as deep as 5 feet (1.5 m) down, so you may need a long key to turn it.
Hook up a small compressor to the mainline with a quick coupler, hose bib, or other type of connection, as determined by the connection located after the backflow device.
You will need a compressor with a CFM (cubic foot per minute) rating of 80 to 100 for any mainline with a diameter of 2 inches (5 cm) or less.Rent the equipment at an equipment rental yard.
Note that a small shop compressor will not have enough air to do the job right.
If you have the original layout for your sprinkler system and it shows the GPM (gallons per minute) running through each sprinkler head, divide the total GPM of each section or zone by
7.5.
This calculation will give you the exact CFM you need to blow the system out.Do not fully charge the holding tank before releasing the pressurized air into the compensator as a way of compensating for less CFM.
Only perform this method if you find a compressor with the right amount of CFM.
Make sure that the compressor valve is in the closed position as you attach the hose to the fitting.
Both valves on the backflow preventer should be closed, as well.
Do not blow compressed air through the backflow device.
Take extra precaution when using highly compressed air.
Compressed air can lead to injury and damage, especially if used improperly. , This station should be on the controller that is in the zone furthest away from the compressor, or the sprinklers at the highest elevation away from the compressor. , Once the backflow valves are closed, slowly open the valve on the compressor to slowly allow air to fill the sprinkler system.
The blow out pressure should always remain below the maximum operating pressure of the lowest pressure rated component in your system.
It should also never exceed 80 PSI for PVC pipe systems, or 50 psi for flexible black polyethylene pipe systems. , Work your way along the system, slowly activating each station or zone.
Activate the stations furthest from the compressor first before working your way to the closest station.
You should activate each station until no additional water can be seen draining from the sprinkler heads.
This can take about two minutes, if not longer, per station.
Consider using two or three short cycles per station rather than one long cycle.
If it seems to take longer than two minutes to drain the water for each station, you may need to deactivate the stations early and repeat the procedure two or three times.
As soon as a station is dry, you should stop blowing air through the pipe.
Blowing compressed air through a dry pipe can create friction and heat, which could damage the pipe.
Never run the compressor without having at least one station valve open.
You should only run air through one zone or section at a time.
If you attempt to do more than that, the excess velocity of the air can add friction and heat to the pipe and fittings, which could cause them to melt. , As soon as the systems have all been dried, disconnect the compressor from the system.
Delaying can cause damage to your pipes.
Open the valves on the system to release any excess air pressure. , If the sprinkler system has a backflow device with ball valves, open and close the isolation valves on the device a few times to force any trapped water to escape.
Leave these isolation valves open at a 45 degree angle and open the test cocks on the system.
About the Author
Helen Reed
Writer and educator with a focus on practical organization knowledge.
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