1. Close the main shut-

    off valve (A).

2. Open the inlet drain


3. Open the inlet and

    outlet ball valves 45

    degrees (C&D) (half

    open, half closed.)

4. Open all testcocks

5. Open the outlet


6. Loosen the cover on

    the #2 check valve

    until all water


7. Loosen the cover on

    the relief valve to

    allow water both

    sides of diaphragm

    to drain.

8. If you “blowout” the

    piping downstream

    of the backflow

    assembly using

    compressed air:

    - Connect the air

       supply to the outlet

       drain and close the

       outlet ball valve.

     - After clearing the

       system with air,

       partially open the

       outlet ball valve.

    - Leave all drain

      valves, testcocks

      and ball valves in a

      half open, half

      closed position for

      the winter.

     - Make sure the

       main shut-off valve

       remains closed and

      does not leak.

  (See photo on right)  



Sprinkler System Winterization

Maintenance & Watering Guidelines


Wyoming winters are unpredictable and the first freeze can happen at any time. By taking preventative steps, damage to sprinkler systems can be avoided.

Winterization of sprinkler systems can be done by the homeowner, or by calling an irrigation technician. There are a number of methods used to winterize different irrigation systems

  • Manual Drain Method
  • utomatic Drain Method
  • “Blow Out” Method

If the homeowner is unaware of the type of irrigation system they have, it is best to use the “Blow Out” Method. Remember to use extreme caution and safe practices while blowing out an irrigation system, as this method utilizes compressed air with a CFM, or Cubic Foot per minute rating of 80-100 for any mainline of two (2)  inches or less.

Some common “Do Not’s” when using the Blowout method include:

  1. Do not allow the air pressure to exceed 80 PSI for systems with PVC pipe, and 50 PSI for systems with polyethylene pipe
  2. Do not stand over component parts while the system is pressurized with air.
  3. Do not leave the air compressor unattended.
  4. Do not blow the system out through a backflow or pump.
  5. Do not leave the manual drain valve open after the blowout.

 Again, use caution while doing an irrigation system blow out, or call Scotch Boy Inc. at 307-778-2838 to make an appointment. 

Phone: (307) 778-2838

Fax: (775) 535-6315


Scotch Boy, Inc.